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Nisha Aji K, Cisbani G, Weidenauer A, Koppel A, Hafizi S, Da Silva T, Kiang M, Rusjan PM, Bazinet RP, Mizrahi R. Neurofilament light-chain (NfL) and 18 kDa translocator protein in early psychosis and its putative high-risk. Brain Behav Immun Health 2024; 37:100742. [PMID: 38495956 PMCID: PMC10940889 DOI: 10.1016/j.bbih.2024.100742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/27/2023] [Accepted: 02/15/2024] [Indexed: 03/19/2024] Open
Abstract
Evidence of elevated peripheral Neurofilament light-chain (NfL) as a biomarker of neuronal injury can be utilized to reveal nonspecific axonal damage, which could reflect altered neuroimmune function. To date, only a few studies have investigated NfL as a fluid biomarker in schizophrenia primarily, though none in its putative prodrome (Clinical High-Risk, CHR) or in untreated first-episode psychosis (FEP). Further, it is unknown whether peripheral NfL is associated with 18 kDa translocator protein (TSPO), a validated neuroimmune marker. In this secondary study, we investigated for the first time (1) serum NfL in early stages of psychosis including CHR and FEP as compared to healthy controls, and (2) examined its association with brain TSPO, using [18F]FEPPA positron emission tomography (PET). Further, in the exploratory analyses, we aimed to assess associations between serum NfL and symptom severity in patient group and cognitive impairment in the combined cohort. A large cohort of 84 participants including 27 FEP (24 antipsychotic-naive), 41 CHR (34 antipsychotic-naive) and 16 healthy controls underwent structural brain MRI and [18F]FEPPA PET scan and their blood samples were obtained and assessed for serum NfL concentrations. We found no significant differences in serum NfL levels across clinical groups, controlling for age. We also found no significant association between NfL levels and brain TSPO in the entire cohort. We observed a negative association between serum NfL and negative symptom severity in CHR. Our findings suggest that neither active neuroaxonal deterioration as measured with NfL nor associated neuroimmune activation (TSPO) is clearly identifiable in an early mostly untreated psychosis sample including its putative high-risk.
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Affiliation(s)
- Kankana Nisha Aji
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Giulia Cisbani
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Ana Weidenauer
- Division of General Psychiatry, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Alex Koppel
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Pablo M. Rusjan
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Richard P. Bazinet
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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Lepock JR, Sanches M, Ahmed S, Gerritsen CJ, Korostil M, Mizrahi R, Kiang M. N400 event-related brain potential index of semantic processing and two-year clinical outcomes in persons at high risk for psychosis: A longitudinal study. Eur J Neurosci 2024; 59:1877-1888. [PMID: 37386749 DOI: 10.1111/ejn.16074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 05/24/2023] [Accepted: 06/13/2023] [Indexed: 07/01/2023]
Abstract
The N400 event-related brain potential (ERP) semantic priming effect reflects greater activation of contextually related versus unrelated concepts in long-term semantic memory. Deficits in this measure have been found in persons with schizophrenia and those at clinical high risk (CHR) for this disorder. In CHR patients, we previously found that these deficits predict poorer social functional outcomes after 1 year. In the present study, we tested whether these deficits predicted greater psychosis-spectrum symptom severity and functional impairment over 2 years. We measured N400 semantic priming effects at baseline in CHR patients (n = 47) who viewed prime words each followed by a related/unrelated target word at stimulus-onset asynchronies (SOAs) of 300 or 750 ms. We measured psychosis-spectrum symptoms using the Structured Interview for Prodromal Symptoms and role and social functioning with the Global Functioning: Role and Social scales, at baseline, 1 (n = 29) and 2 years (n = 25). There was a significant interaction between the N400 semantic priming effect at the 300-ms SOA and time on GF:Role scores, indicating that, contrary to expectations, smaller baseline N400 semantic priming effects were associated with more improvement in role functioning from baseline to Year 1, but baseline N400 priming effects did not predict role functioning at Year 2. N400 priming effects were not significantly associated with different trajectories in psychosis-spectrum symptoms or social functioning. Thus, CHR patients' N400 semantic priming effects did not predict clinical outcomes over 2 years, suggesting that this ERP measure may have greater value as a state or short-term prognostic neurophysiological biomarker.
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Affiliation(s)
| | - Marcos Sanches
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sarah Ahmed
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Cory J Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Michele Korostil
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
- St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada
| | - Romina Mizrahi
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Michael Kiang
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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Lepock JR, Girard T, Cupid J, Kiang M. Effects of anxiety state on N400 event-related brain potential response to unexpected semantic stimuli. Neurosci Lett 2024; 826:137713. [PMID: 38458417 DOI: 10.1016/j.neulet.2024.137713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/26/2024] [Accepted: 03/01/2024] [Indexed: 03/10/2024]
Abstract
Emotional states can influence how people use meaningful context to make predictions about what comes next. To measure whether state anxiety influences such prediction, we used the N400 event-related brain potential (ERP) response to semantic stimuli, whose amplitude is smaller (less negative) when the stimulus is more predicted based on preceding context. Participants (n = 28) were randomized to one of two groups, who underwent either an "anxious-uncertainty" procedure previously shown to increase anxiety, or a control procedure. Both before and after this procedure, participants' ERPs were recorded while they viewed category definitions (e.g., "a type of fruit"), each followed by a target word that was either a high-typicality category exemplar ("apple"), low-typicality exemplar ("cherry"), or non-exemplar ("clamp") of the category. Participants' task was to respond by pressing one of two buttons to indicate whether the target represented a member of the category. As expected, based on previous work, overall, N400 amplitudes were largest (most negative) in response to non-exemplars, intermediate to low-typicality exemplars, and smallest to high-typicality exemplars. N400 amplitudes were larger to non-exemplars after the anxious-uncertainty procedure than after the control procedure. N400 amplitudes to both types of exemplars did not differ after the anxious-uncertainty procedure versus the control procedure. The results are consistent with participants devoting more neural resources to processing contextually unexpected items under anxious states, rather than anxiety facilitating processing of expected items.
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Affiliation(s)
| | - Todd Girard
- Department of Psychology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Justice Cupid
- Department of Psychology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Michael Kiang
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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Agarwal SM, Dissanayake J, Agid O, Bowie C, Brierley N, Chintoh A, De Luca V, Diaconescu A, Gerretsen P, Graff-Guerrero A, Hawco C, Herman Y, Hill S, Hum K, Husain MO, Kennedy JL, Kiang M, Kidd S, Kozloff N, Maslej M, Mueller DJ, Naeem F, Neufeld N, Remington G, Rotenberg M, Selby P, Siddiqui I, Szacun-Shimizu K, Tiwari AK, Thirunavukkarasu S, Wang W, Yu J, Zai CC, Zipursky R, Hahn M, Foussias G. Characterization and prediction of individual functional outcome trajectories in schizophrenia spectrum disorders (PREDICTS study): Study protocol. PLoS One 2023; 18:e0288354. [PMID: 37733693 PMCID: PMC10513234 DOI: 10.1371/journal.pone.0288354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/23/2023] [Indexed: 09/23/2023] Open
Abstract
Schizophrenia spectrum disorders (SSDs) are associated with significant functional impairments, disability, and low rates of personal recovery, along with tremendous economic costs linked primarily to lost productivity and premature mortality. Efforts to delineate the contributors to disability in SSDs have highlighted prominent roles for a diverse range of symptoms, physical health conditions, substance use disorders, neurobiological changes, and social factors. These findings have provided valuable advances in knowledge and helped define broad patterns of illness and outcomes across SSDs. Unsurprisingly, there have also been conflicting findings for many of these determinants that reflect the heterogeneous population of individuals with SSDs and the challenges of conceptualizing and treating SSDs as a unitary categorical construct. Presently it is not possible to identify the functional course on an individual level that would enable a personalized approach to treatment to alter the individual's functional trajectory and mitigate the ensuing disability they would otherwise experience. To address this ongoing challenge, this study aims to conduct a longitudinal multimodal investigation of a large cohort of individuals with SSDs in order to establish discrete trajectories of personal recovery, disability, and community functioning, as well as the antecedents and predictors of these trajectories. This investigation will also provide the foundation for the co-design and testing of personalized interventions that alter these functional trajectories and improve outcomes for people with SSDs.
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Affiliation(s)
- Sri Mahavir Agarwal
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
- Temerty Faculty Institute of Medical Science, University of Toronto, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Centre (BBDC), University of Toronto, Toronto, Canada
| | - Joel Dissanayake
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Ofer Agid
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Christopher Bowie
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Noah Brierley
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Araba Chintoh
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Vincenzo De Luca
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Andreea Diaconescu
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Philip Gerretsen
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Ariel Graff-Guerrero
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Colin Hawco
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Yarissa Herman
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Sean Hill
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Kathryn Hum
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Muhammad Omair Husain
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - James L. Kennedy
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Michael Kiang
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Sean Kidd
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Nicole Kozloff
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Marta Maslej
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Daniel J. Mueller
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Farooq Naeem
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Nicholas Neufeld
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Gary Remington
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Martin Rotenberg
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Peter Selby
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Ishraq Siddiqui
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Kate Szacun-Shimizu
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Arun K. Tiwari
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | | | - Wei Wang
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Joanna Yu
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Clement C. Zai
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Robert Zipursky
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Margaret Hahn
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
- Temerty Faculty Institute of Medical Science, University of Toronto, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Centre (BBDC), University of Toronto, Toronto, Canada
| | - George Foussias
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
- Temerty Faculty Institute of Medical Science, University of Toronto, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
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5
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Nisha Aji K, Hafizi S, Da Silva T, Kiang M, Rusjan PM, Weickert CS, Mizrahi R. Interaction between peripheral and central immune markers in clinical high risk for psychosis. Brain Behav Immun Health 2023; 30:100636. [PMID: 37293440 PMCID: PMC10244662 DOI: 10.1016/j.bbih.2023.100636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 05/07/2023] [Indexed: 06/10/2023] Open
Abstract
Neuroinflammatory events prior to the diagnosis of schizophrenia may play a role in transition to illness. To date only one in-vivo study has investigated this association between peripheral proinflammatory cytokines and brain markers of inflammation (e.g., mitochondrial 18 kDa translocator protein, TSPO) in schizophrenia, but none in its putative prodrome. In this study, we primarily aimed to (Barron et al., 2017) test study group (clinical high-risk (CHR) and healthy controls) differences in peripheral inflammatory markers and test for any associations with symptom measures, (Hafizi et al., 2017a) investigate the interaction between brain TSPO levels (dorsolateral prefrontal cortex (DLPFC) and hippocampus) and peripheral inflammatory clusters (entire cohort and (CHR) group independently) within a relatively large group of individuals at CHR for psychosis (N = 38) and healthy controls (N = 20). Participants underwent structural brain magnetic resonance imaging (MRI) and TSPO [18F]FEPPA positron emission tomography (PET) scans. Serum samples were assessed for peripheral inflammatory markers (i.e., CRP and interleukins). For exploratory analysis, we aimed to examine cluster differences for symptom measures and identify independent peripheral predictors of brain TSPO expression. Here, we report increased IL-8 levels that are positively correlated with prodromal general symptom severity and showed trend-level association with apathy in CHR. We identified distinct inflammatory clusters characterized by inflammatory markers (IL-1 β, IL-2, IFN-γ) that were comparable between entire cohort and CHR. TSPO levels did not differ between inflammatory clusters (entire cohort or CHR). Finally, we show that CRP, IL-1 β, TNF-α, and IFN-γ levels were the independent peripheral predictors of brain TSPO expression. Thus, alterations in brain TSPO expression in response to inflammatory processes are not evident in CHR. Taken together, clustering by inflammatory status is a promising strategy to characterize the interaction between brain TSPO and peripheral markers of inflammation.
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Affiliation(s)
- Kankana Nisha Aji
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Pablo M. Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | | | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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Gerritsen CJ, Goldberg JO, Kiang M, Remington G, Foussias G, Eastwood JD. Distinct profiles of psychological and neuropsychological functions underlying goal-directed pursuit in schizophrenia. Aust N Z J Psychiatry 2022; 56:1628-1641. [PMID: 35191327 DOI: 10.1177/00048674221077031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Several components are known to underlie goal-directed pursuit, including executive, motivational and volitional functions. These were explored in schizophrenia spectrum disorders in order to identify subgroups with distinct profiles. METHODS Multiple executive, motivational and volitional tests were administered to a sample of outpatients with schizophrenia spectrum diagnoses (n = 59) and controls (n = 63). Research questions included whether distinct profiles exist and whether some functions are impacted disproportionately. These questions were addressed via cluster analysis and profile analysis, respectively. RESULTS Some such functions were significantly altered in schizophrenia while others were unaffected. Two distinct profiles emerged, one characterized by energizing deficits, reduced reward sensitivity and few subjective complaints; while another was characterized by markedly increased punishment sensitivity, intact reward sensitivity and substantial subjective reporting of avolitional symptoms and boredom susceptibility. CONCLUSION These findings highlight the importance of considering distinct patterns of strengths and deficits in functions governing goal-directed pursuit in schizophrenia that demarcate identifiable subtypes. These distinctions have implications for treatment, assessment and research.
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Affiliation(s)
- Cory J Gerritsen
- Campbell Family Mental Health Research Institute, Forensic Early Intervention Service, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Joel O Goldberg
- Department of Psychology, York University, Toronto, ON, Canada
| | - Michael Kiang
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Gary Remington
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - George Foussias
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - John D Eastwood
- Department of Psychology, York University, Toronto, ON, Canada
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7
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Bidzinski KK, Lowe DJE, Sanches M, Sorkhou M, Boileau I, Kiang M, Blumberger DM, Remington G, Ma C, Castle DJ, Rabin RA, George TP. Investigating repetitive transcranial magnetic stimulation on cannabis use and cognition in people with schizophrenia. Schizophr 2022; 8:2. [PMID: 35210458 PMCID: PMC8873399 DOI: 10.1038/s41537-022-00210-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 01/11/2022] [Indexed: 11/09/2022]
Abstract
AbstractCannabis use disorder (CUD) occurs at high rates in schizophrenia, which negatively impacts its clinical prognosis. These patients have greater difficulty quitting cannabis which may reflect putative deficits in the dorsolateral prefrontal cortex (DLPFC), a potential target for treatment development. We examined the effects of active versus sham high-frequency (20-Hz) repetitive transcranial magnetic stimulation (rTMS) on cannabis use in outpatients with schizophrenia and CUD. Secondary outcomes included cannabis craving/withdrawal, psychiatric symptoms, cognition and tobacco use. Twenty-four outpatients with schizophrenia and CUD were enrolled in a preliminary double-blind, sham-controlled randomized trial. Nineteen participants were randomized to receive active (n = 9) or sham (n = 10) rTMS (20-Hz) applied bilaterally to the DLPFC 5x/week for 4 weeks. Cannabis use was monitored twice weekly. A cognitive battery was administered pre- and post-treatment. rTMS was safe and well-tolerated with high treatment retention (~90%). Contrast estimates suggested greater reduction in self-reported cannabis use (measured in grams/day) in the active versus sham group (Estimate = 0.33, p = 0.21; Cohen’s d = 0.72), suggesting a clinically relevant effect of rTMS. A trend toward greater reduction in craving (Estimate = 3.92, p = 0.06), and significant reductions in PANSS positive (Estimate = 2.42, p = 0.02) and total (Estimate = 5.03, p = 0.02) symptom scores were found in the active versus sham group. Active rTMS also improved attention (Estimate = 6.58, p < 0.05), and suppressed increased tobacco use that was associated with cannabis reductions (Treatment x Time: p = 0.01). Our preliminary findings suggest that rTMS to the DLPFC is safe and potentially efficacious for treating CUD in schizophrenia.
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Lepock JR, Mizrahi R, Gerritsen CJ, Bagby RM, Maheandiran M, Ahmed S, Korostil M, Kiang M. N400 event-related brain potential and functional outcome in persons at clinical high risk for psychosis: A longitudinal study. Psychiatry Clin Neurosci 2022; 76:114-121. [PMID: 35037344 DOI: 10.1111/pcn.13330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/10/2021] [Accepted: 12/27/2021] [Indexed: 12/01/2022]
Abstract
BACKGROUND The N400 event-related brain potential (ERP) semantic priming effect is thought to reflect activation by meaningful stimuli of related concepts in semantic memory and has been found to be deficient in schizophrenia. We tested the hypothesis that, among individuals at clinical high risk (CHR) for psychosis, N400 semantic priming deficits predict worse symptomatic and functional outcomes after one year. METHODS We measured N400 semantic priming at baseline in CHR patients (n = 47) and healthy control participants (n = 25) who viewed prime words each followed by a related or unrelated target word, at stimulus-onset asynchronies (SOAs) of 300 or 750 ms. We measured patients' psychosis-like symptoms with the Scale of Prodromal Symptoms (SOPS) Positive subscale, and academic/occupational and social functioning with the Global Functioning (GF):Role and Social scales, respectively, at baseline and one-year follow-up (n = 29). RESULTS CHR patients exhibited less N400 semantic priming than controls across SOAs; planned contrasts indicated this difference was significant at the 750-ms but not the 300-ms SOA. In patients, reduced N400 semantic priming at the 750-ms SOA was associated with lower GF:Social scores at follow-up, and greater GF:Social decrements from baseline to follow-up. Patients' N400 semantic priming was not associated with SOPS Positive or GF:Role scores at follow-up, or change in these from baseline to follow-up. CONCLUSIONS In CHR patients, reduced N400 semantic priming at baseline predicted worse social functioning after one year, and greater decline in social functioning over this period. Thus, the N400 may be a useful prognostic biomarker of real-world functional outcome in CHR patients.
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Affiliation(s)
- Jennifer R Lepock
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Cory J Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | - R Michael Bagby
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | | | - Sarah Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Michele Korostil
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada.,St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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9
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Ahmed S, Lepock JR, Mizrahi R, Bagby RM, Gerritsen CJ, Korostil M, Light GA, Kiang M. Decreased Gamma Auditory Steady-State Response Is Associated With Impaired Real-World Functioning in Unmedicated Patients at Clinical High Risk for Psychosis. Clin EEG Neurosci 2021; 52:400-405. [PMID: 33356513 DOI: 10.1177/1550059420982706] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AIM Deficits in synchronous, gamma-frequency neural oscillations may contribute to schizophrenia patients' real-world functional impairment and can be measured electroencephalographically using the auditory steady-state response (ASSR). Gamma ASSR deficits have been reported in schizophrenia patients and individuals at clinical high risk (CHR) for developing psychosis. We hypothesized that, in CHR patients, gamma ASSR would correlate with real-world functioning, consistent with a role for gamma synchrony deficits in functional impairment. METHODS A total of 35 CHR patients rated on Global Functioning: Social and Role scales had EEG recorded while listening to 1-ms, 93-dB clicks presented at 40 Hz in 500-ms trains, in response to which 40-Hz evoked power and intertrial phase-locking factor (PLF) were measured. RESULTS In CHR patients, lower 40-Hz PLF correlated with lower social functioning. CONCLUSIONS Gamma synchrony deficits may be a biomarker of real-world impairment at early stages of the schizophrenia disease trajectory.
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Affiliation(s)
- Sarah Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Jennifer R Lepock
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - R Michael Bagby
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | - Cory J Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michele Korostil
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Gregory A Light
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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10
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Lepock JR, Ahmed S, Mizrahi R, Gerritsen CJ, Maheandiran M, Bagby RM, Korostil M, Kiang M. N400 event-related brain potential as an index of real-world and neurocognitive function in patients at clinical high risk for schizophrenia. Early Interv Psychiatry 2021; 15:68-75. [PMID: 31883227 DOI: 10.1111/eip.12911] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/27/2019] [Accepted: 12/14/2019] [Indexed: 11/28/2022]
Abstract
AIM The N400 event-related potential is a neurophysiological index of cognitive processing of real-world knowledge. In healthy populations, N400 amplitude is smaller in response to stimuli that are more related to preceding context. This 'N400 semantic priming effect' is thought to reflect activation of contextually related information in semantic memory (SM). N400 semantic priming deficits have been found in schizophrenia, and in patients at clinical high risk (CHR) for this disorder. Because this abnormality in processing relationships between meaningful stimuli could affect ability to navigate everyday situations, we hypothesized it would be associated with real-world functional impairment in CHR patients. Second, we hypothesized it would correlate with global neurocognitive impairment in this group. METHODS We measured N400 semantic priming in 35 CHR patients who viewed prime words each followed by a related or unrelated target word, at stimulus-onset asynchrony (SOA) of 300 or 750 ms. We measured academic/occupational and social function with the global function (GF): Role and Social scales, and cognitive function with the MATRICS Consensus Cognitive Battery (MCCB). RESULTS Decreased N400 semantic priming at the 300-ms SOA correlated with lower GF:Role scores. Decreased N400 semantic priming at the 750-ms SOA correlated with lower MCCB composite scores. CONCLUSIONS Deficits in activating contextually related concepts in SM over short time intervals may contribute to functional impairment in CHR patients. Furthermore, N400 priming deficits over longer intervals may be a biomarker of global cognitive dysfunction in this population. Longitudinal studies are needed to determine whether these deficits are associated with schizophrenia risk within this population.
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Affiliation(s)
- Jennifer R Lepock
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sarah Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Cory J Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | | | - R Michael Bagby
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michele Korostil
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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11
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Campanella S, Arikan K, Babiloni C, Balconi M, Bertollo M, Betti V, Bianchi L, Brunovsky M, Buttinelli C, Comani S, Di Lorenzo G, Dumalin D, Escera C, Fallgatter A, Fisher D, Giordano GM, Guntekin B, Imperatori C, Ishii R, Kajosch H, Kiang M, López-Caneda E, Missonnier P, Mucci A, Olbrich S, Otte G, Perrottelli A, Pizzuti A, Pinal D, Salisbury D, Tang Y, Tisei P, Wang J, Winkler I, Yuan J, Pogarell O. Special Report on the Impact of the COVID-19 Pandemic on Clinical EEG and Research and Consensus Recommendations for the Safe Use of EEG. Clin EEG Neurosci 2021; 52:3-28. [PMID: 32975150 PMCID: PMC8121213 DOI: 10.1177/1550059420954054] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION The global COVID-19 pandemic has affected the economy, daily life, and mental/physical health. The latter includes the use of electroencephalography (EEG) in clinical practice and research. We report a survey of the impact of COVID-19 on the use of clinical EEG in practice and research in several countries, and the recommendations of an international panel of experts for the safe application of EEG during and after this pandemic. METHODS Fifteen clinicians from 8 different countries and 25 researchers from 13 different countries reported the impact of COVID-19 on their EEG activities, the procedures implemented in response to the COVID-19 pandemic, and precautions planned or already implemented during the reopening of EEG activities. RESULTS Of the 15 clinical centers responding, 11 reported a total stoppage of all EEG activities, while 4 reduced the number of tests per day. In research settings, all 25 laboratories reported a complete stoppage of activity, with 7 laboratories reopening to some extent since initial closure. In both settings, recommended precautions for restarting or continuing EEG recording included strict hygienic rules, social distance, and assessment for infection symptoms among staff and patients/participants. CONCLUSIONS The COVID-19 pandemic interfered with the use of EEG recordings in clinical practice and even more in clinical research. We suggest updated best practices to allow safe EEG recordings in both research and clinical settings. The continued use of EEG is important in those with psychiatric diseases, particularly in times of social alarm such as the COVID-19 pandemic.
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Affiliation(s)
- Salvatore Campanella
- Laboratoire de Psychologie Médicale et d'Addictologie, ULB Neuroscience Institute (UNI), CHU Brugmann-Université Libre de Bruxelles (U.L.B.), Belgium
| | - Kemal Arikan
- Kemal Arıkan Psychiatry Clinic, Istanbul, Turkey
| | - Claudio Babiloni
- Department of Physiology and Pharmacology "Erspamer", Sapienza University of Rome, Italy.,San Raffaele Cassino, Cassino (FR), Italy
| | - Michela Balconi
- Research Unit in Affective and Social Neuroscience, Department of Psychology, Catholic University of Milan, Milan, Italy
| | - Maurizio Bertollo
- BIND-Behavioral Imaging and Neural Dynamics Center, Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - Viviana Betti
- Department of Psychology, Sapienza University of Rome, Fondazione Santa Lucia, Rome, Italy
| | - Luigi Bianchi
- Dipartimento di Ingegneria Civile e Ingegneria Informatica (DICII), University of Rome Tor Vergata, Rome, Italy
| | - Martin Brunovsky
- National Institute of Mental Health, Klecany Czech Republic.,Third Medical Faculty, Charles University, Prague, Czech Republic
| | - Carla Buttinelli
- Department of Neurosciences, Public Health and Sense Organs (NESMOS), Sapienza University of Rome, Rome, Italy
| | - Silvia Comani
- BIND-Behavioral Imaging and Neural Dynamics Center, Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - Giorgio Di Lorenzo
- Laboratory of Psychophysiology and Cognitive Neuroscience, Chair of Psychiatry, Department of Systems Medicine, School of Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy.,IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Daniel Dumalin
- AZ Sint-Jan Brugge-Oostende AV, Campus Henri Serruys, Lab of Neurophysiology, Department Neurology-Psychiatry, Ostend, Belgium
| | - Carles Escera
- Brainlab-Cognitive Neuroscience Research Group, Department of Clinical Psychology and Psychobiology, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Andreas Fallgatter
- Department of Psychiatry, University of Tübingen, Germany; LEAD Graduate School and Training Center, Tübingen, Germany.,German Center for Neurodegenerative Diseases DZNE, Tübingen, Germany
| | - Derek Fisher
- Department of Psychology, Mount Saint Vincent University, and Department of Psychiatry, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
| | | | - Bahar Guntekin
- Department of Biophysics, School of Medicine, Istanbul Medipol University, Istanbul, Turkey
| | - Claudio Imperatori
- Cognitive and Clinical Psychology Laboratory, Department of Human Science, European University of Rome, Rome, Italy
| | - Ryouhei Ishii
- Department of Psychiatry Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hendrik Kajosch
- Laboratoire de Psychologie Médicale et d'Addictologie, ULB Neuroscience Institute (UNI), CHU Brugmann-Université Libre de Bruxelles (U.L.B.), Belgium
| | - Michael Kiang
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Eduardo López-Caneda
- Psychological Neuroscience Laboratory, Center for Research in Psychology, School of Psychology, University of Minho, Braga, Portugal
| | - Pascal Missonnier
- Mental Health Network Fribourg (RFSM), Sector of Psychiatry and Psychotherapy for Adults, Marsens, Switzerland
| | - Armida Mucci
- Department of Psychiatry, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Sebastian Olbrich
- Psychotherapy and Psychosomatics, Department for Psychiatry, University Hospital Zurich, Zurich, Switzerland
| | | | - Andrea Perrottelli
- Department of Psychiatry, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Alessandra Pizzuti
- Department of Psychology, Sapienza University of Rome, Fondazione Santa Lucia, Rome, Italy
| | - Diego Pinal
- Psychological Neuroscience Laboratory, Center for Research in Psychology, School of Psychology, University of Minho, Braga, Portugal
| | - Dean Salisbury
- Clinical Neurophysiology Research Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Yingying Tang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Paolo Tisei
- Department of Neurosciences, Public Health and Sense Organs (NESMOS), Sapienza University of Rome, Rome, Italy
| | - Jijun Wang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Istvan Winkler
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Jiajin Yuan
- Institute of Brain and Psychological Sciences, Sichuan Normal University, Chengdu, China
| | - Oliver Pogarell
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
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12
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Lepock JR, Ahmed S, Mizrahi R, Gerritsen CJ, Maheandiran M, Drvaric L, Bagby RM, Korostil M, Light GA, Kiang M. Relationships between cognitive event-related brain potential measures in patients at clinical high risk for psychosis. Schizophr Res 2020; 226:84-94. [PMID: 30683525 DOI: 10.1016/j.schres.2019.01.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/11/2019] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
Abstract
Neurophysiological measures of cognitive functioning that are abnormal in patients with schizophrenia are promising candidate biomarkers for predicting development of psychosis in individuals at clinical high risk (CHR). We examined the relationships among event-related brain potential (ERP) measures of early sensory, pre-attentional, and attention-dependent cognition, in antipsychotic-naïve help-seeking CHR patients (n = 36) and healthy control participants (n = 22). These measures included the gamma auditory steady-state response (ASSR; early sensory); mismatch negativity (MMN) and P3a (pre-attentional); and N400 semantic priming effects - a measure of using meaningful context to predict related items - over a shorter and a longer time interval (attention-dependent). Compared to controls, CHR patients had significantly smaller P3a amplitudes (d = 0.62, p = 0.03) and N400 priming effects over the long interval (d = 0.64, p = 0.02). In CHR patients, gamma ASSR evoked power and phase-locking factor were correlated (r = 0.41, p = 0.03). Reductions in mismatch negativity (MMN) and P3a amplitudes were also correlated (r = -0.36, p = 0.04). Moreover, lower gamma ASSR evoked power correlated with smaller MMN amplitudes (r = -0.45, p = 0.02). MMN amplitude reduction was also associated with reduced N400 semantic priming over the shorter but not the longer interval (r = 0.52, p < 0.002). This pattern of results suggests that, in a subset of CHR patients, impairment in pre-attentional measures of early information processing may contribute to deficits in attention-dependent cognition involving rapid, more automatic processing, but may be independent from pathological processes affecting more controlled or strategic processing. Thus, combining neurophysiological indices of cognitive deficits in different domains offers promise for improving their predictive power as prognostic biomarkers of clinical outcome.
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Affiliation(s)
- Jennifer R Lepock
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sarah Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Cory J Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | | | - Lauren Drvaric
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - R Michael Bagby
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michele Korostil
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Gregory A Light
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, United States
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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13
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Watts JJ, Jacobson MR, Lalang N, Boileau I, Tyndale RF, Kiang M, Ross RA, Houle S, Wilson AA, Rusjan P, Mizrahi R. Imaging Brain Fatty Acid Amide Hydrolase in Untreated Patients With Psychosis. Biol Psychiatry 2020; 88:727-735. [PMID: 32387132 PMCID: PMC8240477 DOI: 10.1016/j.biopsych.2020.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/01/2020] [Accepted: 03/04/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND The brain's endocannabinoid system, the primary target of cannabis, has been implicated in psychosis. The endocannabinoid anandamide is elevated in cerebrospinal fluid of patients with schizophrenia. Fatty acid amide hydrolase (FAAH) controls brain anandamide levels; however, it is unknown if FAAH is altered in vivo in psychosis or related to positive psychotic symptoms. METHODS Twenty-seven patients with schizophrenia spectrum disorders and 36 healthy control subjects completed high-resolution positron emission tomography scans with the novel FAAH radioligand [11C]CURB and structural magnetic resonance imaging. Data were analyzed using the validated irreversible 2-tissue compartment model with a metabolite-corrected arterial input function. RESULTS FAAH did not differ significantly between patients with psychotic disorders and healthy control subjects (F1,62.85 = 0.48, p = .49). In contrast, lower FAAH predicted greater positive psychotic symptom severity, with the strongest effect observed for the positive symptom dimension, which includes suspiciousness, delusions, unusual thought content, and hallucinations (F1,26.69 = 12.42, p = .002; Cohen's f = 0.42, large effect). Shorter duration of illness (F1,26.95 = 13.78, p = .001; Cohen's f = 0.39, medium to large effect) and duration of untreated psychosis predicted lower FAAH (F1,26.95 = 6.03, p = .021, Cohen's f = 0.27, medium effect). These results were not explained by past cannabis exposure or current intake of antipsychotic medications. FAAH exhibited marked differences across brain regions (F7,112.62 = 175.85, p < 1 × 10-56; Cohen's f > 1). Overall, FAAH was higher in female subjects than in male subjects (F1,62.84 = 10.05, p = .002; Cohen's f = 0.37). CONCLUSIONS This first study of brain FAAH in psychosis indicates that FAAH may represent a biomarker of disease state of potential utility for clinical studies targeting psychotic symptoms or as a novel target for interventions to treat psychotic symptoms.
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Affiliation(s)
- Jeremy J Watts
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Maya R Jacobson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Nittha Lalang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Isabelle Boileau
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Ruth A Ross
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Pablo Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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14
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Gerritsen C, Maheandiran M, Lepock J, Ahmed S, Kiang M, Bagby RM, Mizrahi R. Negative symptoms in the clinical high-risk state for psychosis: Connection with cognition and primacy in impacting functioning. Early Interv Psychiatry 2020; 14:188-195. [PMID: 31264790 DOI: 10.1111/eip.12843] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 05/30/2019] [Accepted: 06/09/2019] [Indexed: 12/14/2022]
Abstract
AIM In the clinical high-risk (CHR) state for psychosis, both negative symptoms and lower cognitive function have been associated with poorer daily functioning. Recent evidence suggests that negative symptoms share overlapping variability with cognition and may partially mediate the relationship between cognition and functioning. However, the nature of this overlap is unknown, and the reverse mediation model remains untested leaving the precise nature of these associations unclear. METHODS In order to clarify these relationships, a sample of community-dwelling youth meeting CHR criteria was collected from a specialty CHR clinic (n = 91, mean age = 21, 63% male). Bootstrapping methods were then applied in a mediation analysis to test both negative symptoms and cognition as independent variables and mediating variables predicting social and role functioning in CHR individuals. Canonical correlation analysis was used to characterize the overlapping variability between negative symptoms and cognition. RESULTS Support for a primary role of negative symptoms in predicting functioning and cognition was observed. Canonical correlation revealed a single dimension of overlap between the two symptom types (r = .62), represented by a strong correlation between negative symptoms in general and tasks involving verbal working memory, vigilance and social cognition specifically. A single cognitive factor composed primarily of these tasks was found to predict role functioning (adjusted R 2 = .04). CONCLUSIONS The results highlight the importance of considering specific cognitive mechanisms overlapping with negative symptoms in research and rehabilitative practice in CHR populations, as well as the primary importance of targeting negative symptoms.
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Affiliation(s)
- Cory Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | | | - Jenny Lepock
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Sarah Ahmed
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Robert Michael Bagby
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
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15
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Kiang M, Cupid J, Ahmed S, Lepock JR, Girard TA. Religiosity is associated with less prediction of the typical: An event-related brain potential study. Biol Psychol 2020; 153:107884. [PMID: 32234502 DOI: 10.1016/j.biopsycho.2020.107884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/04/2020] [Accepted: 03/23/2020] [Indexed: 11/26/2022]
Abstract
Why are some people more religious than others? According to one hypothesis, people who strongly seek definitive explanations for situations with incomplete information are more likely to be religious. According to a different hypothesis, individuals with smaller "prediction error" responses to unexpected stimuli are more likely to discount evidence contradicting religious beliefs, predisposing them to maintain such beliefs. We sought neurophysiological evidence for these hypotheses using the N400 event-related potential (ERP), which is smaller to more contextually expected stimuli, reflecting prediction of probable completions for meaningful situations. We recorded ERPs from participants viewing category definitions followed by high-typicality category exemplar (HTE), low-typicality exemplar (LTE), or non-exemplar (NE) words. As expected, N400s were largest for NEs, intermediate for LTEs, and smallest for HTEs. Religiosity correlated with smaller N400 amplitude differences between HTEs and both LTEs and NEs. Less strong prediction of probable stimuli based on prior information may predispose to religiosity.
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Affiliation(s)
- Michael Kiang
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | - Justice Cupid
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychology, Ryerson University, Toronto, ON, Canada
| | - Sarah Ahmed
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Jennifer R Lepock
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Todd A Girard
- Department of Psychology, Ryerson University, Toronto, ON, Canada
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16
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Wilkins LK, Girard TA, Christensen BK, King J, Kiang M, Bohbot VD. Spontaneous spatial navigation circuitry in schizophrenia spectrum disorders. Psychiatry Res 2019; 278:125-128. [PMID: 31174032 DOI: 10.1016/j.psychres.2019.05.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/17/2019] [Accepted: 05/19/2019] [Indexed: 11/30/2022]
Abstract
Spatial memory is core to wayfinding and everyday memory. Interestingly, individuals with schizophrenia using spatial navigation strategies (cognitive mapping) are impaired, whereas those using response-based (e.g., single-landmark) strategies show relatively intact memory performance. We observed abnormal brain communication in schizophrenia participants who used a spatial strategy during a virtual-reality navigation task, particularly between temporal and frontal brain regions. In contrast, schizophrenia participants using a response strategy recruited similar brain systems to healthy participants, but to a greater extent to support memory performance. These findings highlight that strategy use is an important consideration for understanding memory systems and navigation in schizophrenia.
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Affiliation(s)
- Leanne K Wilkins
- Department of Psychology, Ryerson University, 350 Victoria St, Toronto, ON M5B 2K3, Canada.
| | - Todd A Girard
- Department of Psychology, Ryerson University, 350 Victoria St, Toronto, ON M5B 2K3, Canada.
| | - Bruce K Christensen
- St. Joseph's Healthcare Hamilton, and Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
| | - Jelena King
- St. Joseph's Healthcare Hamilton, and Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
| | - Michael Kiang
- St. Joseph's Healthcare Hamilton, and Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
| | - Veronique D Bohbot
- Douglas Institute, and Department of Psychiatry, McGill University, Montreal, QC, Canada.
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17
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Gerritsen C, Bagby RM, Sanches M, Kiang M, Maheandiran M, Prce I, Mizrahi R. Stress precedes negative symptom exacerbations in clinical high risk and early psychosis: A time-lagged experience sampling study. Schizophr Res 2019; 210:52-58. [PMID: 31248749 DOI: 10.1016/j.schres.2019.06.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/15/2019] [Accepted: 06/17/2019] [Indexed: 12/18/2022]
Abstract
The experience sampling method (ESM) has revealed associations between fluctuations in stress and positive symptoms in psychosis. It is unknown, however, how negative symptoms including anhedonia respond to stress. Stress is divided according to its source: event-related stress stemming from negative events, and activity-related stress stemming from engaging in tasks beyond one's skill or control. Anhedonia is divided into consummatory and anticipatory anhedonia, reflecting a lack of pleasure in current and expected activities. This study uses ESM to determine whether each form of anhedonia increases in response to stress. Antipsychotic-naïve individuals with first episode psychosis (n = 39), clinical high-risk states for psychosis (n = 44), and healthy controls (n = 34) responded to daily prompts on a palmtop computer for up to ten days by indicating levels of stress and anhedonia. Time-lagged multilevel modelling was employed to explore increases in anhedonia following increases in stress while controlling for prior levels of anhedonia. Mean levels of anhedonia were also compared across groups. Only activity-related stress produced increases in anhedonia. This effect did not vary between groups. Clinical groups showed greater overall levels of anhedonia than healthy controls, but did not differ from each other. Anhedonia responds only to activity-related stressors, suggesting that this form of stress has a specific causal role in anhedonia. The results also provide further evidence for global increases in anhedonia in antipsychotic-naïve psychosis spectrum individuals.
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Affiliation(s)
- Cory Gerritsen
- Centre for Addiction and Mental Health, 250 College St, Toronto, Ontario M5T 1R8, Canada; University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada.
| | - R Michael Bagby
- Centre for Addiction and Mental Health, 250 College St, Toronto, Ontario M5T 1R8, Canada; University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada.
| | - Marcos Sanches
- Centre for Addiction and Mental Health, 250 College St, Toronto, Ontario M5T 1R8, Canada.
| | - Michael Kiang
- Centre for Addiction and Mental Health, 250 College St, Toronto, Ontario M5T 1R8, Canada; University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada.
| | - Margaret Maheandiran
- Centre for Addiction and Mental Health, 250 College St, Toronto, Ontario M5T 1R8, Canada.
| | - Ivana Prce
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, Ontario M4N 3M5, Canada.
| | - Romina Mizrahi
- Centre for Addiction and Mental Health, 250 College St, Toronto, Ontario M5T 1R8, Canada; University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada.
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18
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Lepock JR, Mizrahi R, Korostil M, Maheandiran M, Gerritsen CJ, Drvaric L, Ahmed S, Bagby RM, Kiang M. N400 event-related brain potential evidence for semantic priming deficits in persons at clinical high risk for psychosis. Schizophr Res 2019; 204:434-436. [PMID: 30193760 DOI: 10.1016/j.schres.2018.08.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 08/25/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Jennifer R Lepock
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Michele Korostil
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | | | - Cory J Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Lauren Drvaric
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Sarah Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - R Michael Bagby
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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19
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Hafizi S, Guma E, Koppel A, Da Silva T, Kiang M, Houle S, Wilson AA, Rusjan PM, Chakravarty MM, Mizrahi R. TSPO expression and brain structure in the psychosis spectrum. Brain Behav Immun 2018; 74:79-85. [PMID: 29906515 PMCID: PMC6289857 DOI: 10.1016/j.bbi.2018.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/06/2018] [Accepted: 06/09/2018] [Indexed: 01/18/2023] Open
Abstract
Psychosis is associated with abnormal structural changes in the brain including decreased regional brain volumes and abnormal brain morphology. However, the underlying causes of these structural abnormalities are less understood. The immune system, including microglial activation, has been implicated in the pathophysiology of psychosis. Although previous studies have suggested a connection between peripheral proinflammatory cytokines and structural brain abnormalities in schizophrenia, no in-vivo studies have investigated whether microglial activation is also linked to brain structure alterations previously observed in schizophrenia and its putative prodrome. In this study, we investigated the link between mitochondrial 18 kDa translocator protein (TSPO) and structural brain characteristics (i.e. regional brain volume, cortical thickness, and hippocampal shape) in key brain regions such as dorsolateral prefrontal cortex and hippocampus of a large group of participants (N = 90) including individuals at clinical high risk (CHR) for psychosis, first-episode psychosis (mostly antipsychotic-naïve) patients, and healthy volunteers. The participants underwent structural brain MRI scan and [18F]FEPPA positron emission tomography (PET) targeting TSPO. A significant [18F]FEPPA binding-by-group interaction was observed in morphological measures across the left hippocampus. In first-episode psychosis, we observed associations between [18F]FEPPA VT (total volume of distribution) and outward and inward morphological alterations, respectively, in the dorsal and ventro-medial portions of the left hippocampus. These associations were not significant in CHR or healthy volunteers. There was no association between [18F]FEPPA VT and other structural brain characteristics. Our findings suggest a link between TSPO expression and alterations in hippocampal morphology in first-episode psychosis.
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Affiliation(s)
- Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Elisa Guma
- Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
| | - Alex Koppel
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Alan A. Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Pablo M. Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - M. Mallar Chakravarty
- Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada,Departments of Psychiatry and Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
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20
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Shakory S, Watts JJ, Hafizi S, Da Silva T, Khan S, Kiang M, Bagby RM, Chavez S, Mizrahi R. Hippocampal glutamate metabolites and glial activation in clinical high risk and first episode psychosis. Neuropsychopharmacology 2018; 43:2249-2255. [PMID: 30087434 PMCID: PMC6135774 DOI: 10.1038/s41386-018-0163-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 02/06/2023]
Abstract
Alterations in glutamate neurotransmission have been implicated in the pathophysiology of schizophrenia, as well as in symptom severity and cognitive deficits. The hippocampus, in particular, is a site of key functional and structural abnormalities in schizophrenia. Yet few studies have investigated hippocampal glutamate in antipsychotic-naïve first episode psychosis patients or in individuals at clinical high risk (CHR) of developing psychosis. Using proton magnetic resonance spectroscopy (1H-MRS), we investigated glutamate metabolite levels in the left hippocampus of 25 CHR (19 antipsychotic-naïve), 16 patients with first-episode psychosis (13 antipsychotic-naïve) and 31 healthy volunteers. We also explored associations between hippocampal glutamate metabolites and glial activation, as indexed by [18F]FEPPA positron emission tomography (PET); symptom severity; and cognitive function. Groups differed significantly in glutamate plus glutamine (Glx) levels (F(2, 69) = 6.39, p = 0.003). Post-hoc analysis revealed that CHR had significantly lower Glx levels than both healthy volunteers (p = 0.003) and first-episode psychosis patients (p = 0.050). No associations were found between glutamate metabolites and glial activation. Our findings suggest that glutamate metabolites are altered in CHR.
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Affiliation(s)
- Shima Shakory
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Jeremy J Watts
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Saad Khan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - R Michael Bagby
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Sofia Chavez
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
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21
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Drvaric L, Bagby RM, Kiang M, Mizrahi R. Maladaptive personality traits in patients identified at lower-risk and higher-risk for psychosis. Psychiatry Res 2018; 268:348-353. [PMID: 30098542 DOI: 10.1016/j.psychres.2018.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/25/2018] [Accepted: 08/01/2018] [Indexed: 11/27/2022]
Abstract
The 'at-risk' state for psychosis is a high-risk paradigm that examines factors that contribute to conversion to a first episode of psychosis. Although a multitude of contributing factors have been identified in one's susceptibility to conversion to psychosis, dimensional pathological personality traits have not been examined in 'at-risk' populations. In this study we examine lower- versus higher-risk for psychosis using traits from the DSM-5 Alternative Dimensional Model of Personality Disorders (AMPD) to investigate which AMPD personality traits distinguish those 'at-risk' patients at relatively lower-risk for conversion to psychosis versus those at higher-risk. Remitted schizophrenic patients served as the comparison group. MANOVA analyses revealed significant group differences on the PID-5, with the higher-risk patients scoring higher on two of the five AMPD trait domains - Negative Affectivity and Detachment - compared to lower-risk patients. Maladaptive personality traits from the AMPD may serve as potential risk factor for conversion to psychosis.
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Affiliation(s)
- Lauren Drvaric
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - R Michael Bagby
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
| | - Michael Kiang
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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22
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Hafizi S, Da Silva T, Meyer JH, Kiang M, Houle S, Remington G, Prce I, Wilson AA, Rusjan PM, Sailasuta N, Mizrahi R. Interaction between TSPO-a neuroimmune marker-and redox status in clinical high risk for psychosis: a PET-MRS study. Neuropsychopharmacology 2018; 43:1700-1705. [PMID: 29748630 PMCID: PMC6006145 DOI: 10.1038/s41386-018-0061-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/14/2018] [Accepted: 03/19/2018] [Indexed: 12/25/2022]
Abstract
Altered neuroimmune response and oxidative stress have both been implicated in the pathophysiology of schizophrenia. While preclinical studies have proposed several pathways regarding potential interactions between oxidative stress and neuroimmune imbalance in the development of psychosis, the molecular mechanisms underlying this interaction are not yet understood. To date, no study has investigated this link in vivo in the human brain. We conducted the first in vivo study linking translocator protein 18 kDa (TSPO) expression and glutathione (a major brain antioxidant and a marker for redox status) in the medial prefrontal cortex (mPFC) of a relatively large sample of participants (N = 48) including 27 antipsychotic-naïve individuals at clinical high risk for psychosis and 21 matched healthy volunteers using high-resolution PET with TSPO radioligand, [18F]FEPPA, and 3T proton magnetic resonance spectroscopy (1H MRS). The omnibus model (including TSPO genotype as covariate) was significant (F(4, 43) = 10.01, p < 0.001), with a significant group interaction (t = -2.10, p = 0.04), suggesting a different relation between [18F]FEPPA VT and glutathione in each clinical group. In healthy volunteers, but not in individuals at clinical high risk for psychosis, we found a significant negative association between glutathione levels and [18F]FEPPA VT (r = -0.60, p = 0.006). We observed no significant group differences with respect to [18F]FEPPA VT or glutathione levels. These findings suggest an abnormal interaction between TSPO expression and redox status in the clinical high risk states for psychosis.
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Affiliation(s)
- Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Jeffrey H Meyer
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Gary Remington
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Ivana Prce
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Pablo M Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Napapon Sailasuta
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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23
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Lepock JR, Mizrahi R, Korostil M, Bagby RM, Pang EW, Kiang M. Event-Related Potentials in the Clinical High-Risk (CHR) State for Psychosis: A Systematic Review. Clin EEG Neurosci 2018; 49:215-225. [PMID: 29382210 DOI: 10.1177/1550059418755212] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
There is emerging evidence that identification and treatment of individuals in the prodromal or clinical high-risk (CHR) state for psychosis can reduce the probability that they will develop a psychotic disorder. Event-related brain potentials (ERPs) are a noninvasive neurophysiological technique that holds promise for improving our understanding of neurocognitive processes underlying the CHR state. We aimed to systematically review the current literature on cognitive ERP studies of the CHR population, in order to summarize and synthesize the results, and their implications for our understanding of the CHR state. Across studies, amplitudes of the auditory P300 and duration mismatch negativity (MMN) ERPs appear reliably reduced in CHR individuals, suggesting that underlying impairments in detecting changes in auditory stimuli are a sensitive early marker of the psychotic disease process. There are more limited data indicating that an earlier-latency auditory ERP response, the N100, is also reduced in amplitude, and in the degree to which it is modulated by stimulus characteristics, in the CHR population. There is also evidence that a number of auditory ERP measures (including P300, MMN and N100 amplitudes, and N100 gating in response to repeated stimuli) can further refine our ability to detect which CHR individuals are most at risk for developing psychosis. Thus, further research is warranted to optimize the predictive power of algorithms incorporating these measures, which could help efforts to target psychosis prevention interventions toward those most in need.
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Affiliation(s)
- Jennifer R Lepock
- 1 Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Romina Mizrahi
- 1 Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.,2 Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,3 Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Michele Korostil
- 1 Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.,2 Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,3 Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,4 Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - R Michael Bagby
- 1 Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.,2 Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,3 Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,5 Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth W Pang
- 1 Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.,6 Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada.,7 Neuroscience and Mental Health, SickKids Research Institute, Toronto, Ontario, Canada
| | - Michael Kiang
- 1 Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.,2 Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,3 Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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24
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Schifani C, Tseng HH, Kenk M, Tagore A, Kiang M, Wilson AA, Houle S, Rusjan PM, Mizrahi R. Cortical stress regulation is disrupted in schizophrenia but not in clinical high risk for psychosis. Brain 2018; 141:2213-2224. [PMID: 29860329 PMCID: PMC6022671 DOI: 10.1093/brain/awy133] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/15/2018] [Accepted: 04/02/2018] [Indexed: 12/11/2022] Open
Abstract
While alterations in striatal dopamine in psychosis and stress have been well studied, the role of dopamine in prefrontal cortex is poorly understood. To date, no study has investigated the prefrontocortical dopamine response to stress in the psychosis spectrum, even though the dorsolateral and medial prefrontal cortices are key regions in cognitive and emotional regulation, respectively. The present study uses the high-affinity dopamine D2/3 receptor radiotracer 11C-FLB457 and PET together with a validated psychosocial stress challenge to investigate the dorsolateral and medial prefrontocortical dopamine response to stress in schizophrenia and clinical high risk for psychosis. Forty participants completed two 11C-FLB457 PET scans (14 antipsychotic-free schizophrenia, 14 clinical high risk for psychosis and 12 matched healthy volunteers), one while performing a Sensory Motor Control Task (control) and another while performing the Montreal Imaging Stress Task (stress). Binding potential (BPND) was estimated using Simplified Reference Tissue Model with cerebellar cortex as reference region. Dopamine release was defined as per cent change in BPND between control and stress scans (ΔBPND) using a novel correction for injected mass. Salivary cortisol response (ΔAUCI) was assessed throughout the tasks and its relationship with dopamine release examined. 11C-FLB457 binding at control conditions was significantly different between groups in medial [F(2,37) = 7.98, P = 0.0013] and dorsolateral [F(2,37) = 6.97, P = 0.0027] prefrontal cortex with schizophrenia patients having lower BPND than participants at clinical high risk for psychosis and healthy volunteers, but there was no difference in ΔBPND among groups [dorsolateral prefrontal cortex: F(2,37) = 1.07, P = 0.35; medial prefrontal cortex: F(2,37) = 0.54, P = 0.59]. We report a positive relationship between ΔAUCI and 11C-FLB457 ΔBPND in dorsolateral and medial prefrontal cortex in healthy volunteers (r = 0.72, P = 0.026; r = 0.76, P = 0.014, respectively) and in participants at clinical high risk for psychosis (r = 0.76, P = 0.0075; r = 0.72, P = 0.018, respectively), which was absent in schizophrenia (r = 0.46, P = 1.00; r = 0.19, P = 1.00, respectively). Furthermore, exploratory associations between ΔBPND or ΔAUCI and stress or anxiety measures observed in clinical high risk for psychosis were absent in schizophrenia. These findings provide first direct evidence of a disrupted prefrontocortical dopamine-stress regulation in schizophrenia.
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Affiliation(s)
- Christin Schifani
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Huai-Hsuan Tseng
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Miran Kenk
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Abanti Tagore
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Pablo M Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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25
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Ramlakhan JU, Zomorrodi R, Downar J, Blumberger DM, Daskalakis ZJ, George TP, Kiang M, Barr MS. Using Mismatch Negativity to Investigate the Pathophysiology of Substance Use Disorders and Comorbid Psychosis. Clin EEG Neurosci 2018; 49:226-237. [PMID: 29502434 DOI: 10.1177/1550059418760077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Substance use disorders (SUDs) have a devastating impact on society and place a heavy burden on health care systems. Given that alcohol, tobacco, and cannabis use have the highest prevalence, further understanding of the underlying pathophysiology of these SUDs is crucial. Electroencephalography is an inexpensive, temporally superior, and translatable technique which enables investigation of the pathobiology of SUDs through the evaluation of various event-related potential components, including mismatch negativity (MMN). The goals of this review were to investigate the effects of acute and chronic alcohol, tobacco, and cannabis use on MMN among nonpsychiatric populations and patients with comorbid psychosis. A literature search was performed using the database PubMed, and 36 articles met our inclusion and exclusion criteria. We found a pattern of attenuation of MMN amplitude among patients with alcoholism across acute and chronic alcohol use, and this dysregulation was not heritable. Reports were limited, and results were mixed on the effects of acute and chronic tobacco and cannabis use on MMN. Reports on comorbid SUDs and psychosis were even fewer, and also presented mixed findings. These preliminary results suggest that MMN deficits may be associated with SUDs, specifically alcohol use disorder, and serve as a possible biomarker for treating these common disorders.
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Affiliation(s)
- Jessica U Ramlakhan
- 1 Temerty Centre for Therapeutic Brain Intervention, Division of Mood and Anxiety, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,2 Biobehavioural Addictions and Concurrent Disorders Research Laboratory (BACDRL), Additions Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Reza Zomorrodi
- 1 Temerty Centre for Therapeutic Brain Intervention, Division of Mood and Anxiety, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Jonathan Downar
- 3 Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,4 Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,5 Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Daniel M Blumberger
- 1 Temerty Centre for Therapeutic Brain Intervention, Division of Mood and Anxiety, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,4 Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,5 Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Zafiris J Daskalakis
- 1 Temerty Centre for Therapeutic Brain Intervention, Division of Mood and Anxiety, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,4 Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,5 Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Tony P George
- 2 Biobehavioural Addictions and Concurrent Disorders Research Laboratory (BACDRL), Additions Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,4 Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,5 Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- 1 Temerty Centre for Therapeutic Brain Intervention, Division of Mood and Anxiety, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,4 Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,5 Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Mera S Barr
- 1 Temerty Centre for Therapeutic Brain Intervention, Division of Mood and Anxiety, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,4 Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,5 Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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Tseng HH, Watts JJ, Kiang M, Suridjan I, Wilson AA, Houle S, Rusjan PM, Mizrahi R. Nigral Stress-Induced Dopamine Release in Clinical High Risk and Antipsychotic-Naïve Schizophrenia. Schizophr Bull 2018; 44:542-551. [PMID: 29036383 PMCID: PMC5890468 DOI: 10.1093/schbul/sbx042] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background Striatal dopamine (DA) synthesis capacity and release are elevated in schizophrenia (SCZ) and its putative prodrome, the clinical high risk (CHR) state. Striatal DA function results from the activity of midbrain DA neurons projecting mainly from the substantia nigra (SN). Elevated stress-induced DA release in SCZ and CHR was observed in the striatum; however, whether it is also elevated in the SN is unclear. The current study aims to determine whether nigral DA release in response to a validated stress task is altered in CHR and in antipsychotic-naïve SCZ. Further, we explore how DA release in the SN and striatum might be related. Methods 24 CHR subjects, 9 antipsychotic-naïve SCZ and 25 healthy volunteers (HV) underwent 2 positron emission tomography (PET) scans using the DA D2/3 agonist radiotracer, [11C]-(+)-PHNO, which allows simultaneous investigations of DA in the SN and striatum. Psychosocial stress-induced DA release was estimated as the percentage differences in BPND (%[11C]-(+)-PHNO displacement) between stress and sensory-motor control sessions. Results We observed a significant diagnostic group by session interaction, such that SCZ exhibited greater stress-induced [11C]-(+)-PHNO % displacement (25.90% ± 32.2%; mean ± SD), as compared to HVs (-10.94% ± 27.1%). Displacement in CHRs (-1.13% ± 32.2%) did not differ significantly from either HV or SCZ. Conclusion Our findings suggest that elevated nigral DA responsiveness to stress is observed in antipsychotic-naïve SCZ.
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Affiliation(s)
- Huai-Hsuan Tseng
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Jeremy J Watts
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Ivonne Suridjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Pablo M Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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Wilkins LK, Girard TA, Herdman KA, Christensen BK, King J, Kiang M, Bohbot VD. Hippocampal activation and memory performance in schizophrenia depend on strategy use in a virtual maze. Psychiatry Res Neuroimaging 2017; 268:1-8. [PMID: 28780430 DOI: 10.1016/j.pscychresns.2017.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/20/2017] [Accepted: 07/30/2017] [Indexed: 11/23/2022]
Abstract
Different strategies may be spontaneously adopted to solve most navigation tasks. These strategies are associated with dissociable brain systems. Here, we use brain-imaging and cognitive tasks to test the hypothesis that individuals living with Schizophrenia Spectrum Disorders (SSD) have selective impairment using a hippocampal-dependent spatial navigation strategy. Brain activation and memory performance were examined using functional magnetic resonance imaging (fMRI) during the 4-on-8 virtual maze (4/8VM) task, a human analog of the rodent radial-arm maze that is amenable to both response-based (egocentric or landmark-based) and spatial (allocentric, cognitive mapping) strategies to remember and navigate to target objects. SSD (schizophrenia and schizoaffective disorder) participants who adopted a spatial strategy performed more poorly on the 4/8VM task and had less hippocampal activation than healthy comparison participants using either strategy as well as SSD participants using a response strategy. This study highlights the importance of strategy use in relation to spatial cognitive functioning in SSD. Consistent with a selective-hippocampal dependent deficit in SSD, these results support the further development of protocols to train impaired hippocampal-dependent abilities or harness non-hippocampal dependent intact abilities.
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Affiliation(s)
- Leanne K Wilkins
- Department of Psychology, Ryerson University, 350 Victoria St, Toronto, ON, Canada M5B 2K3
| | - Todd A Girard
- Department of Psychology, Ryerson University, 350 Victoria St, Toronto, ON, Canada M5B 2K3.
| | | | - Bruce K Christensen
- Research School of Psychology, Australian National University, Canberra, ACT, Australia
| | - Jelena King
- St. Joseph's Healthcare Hamilton, and Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
| | - Michael Kiang
- Centre for Addiction and Mental Health, and Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Veronique D Bohbot
- Douglas Institute, and Department of Psychiatry, McGill University, Montreal, QC, Canada
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Da Silva T, Hafizi S, Andreazza AC, Kiang M, Bagby RM, Navas E, Laksono I, Truong P, Gerritsen C, Prce I, Sailasuta N, Mizrahi R. Glutathione, the Major Redox Regulator, in the Prefrontal Cortex of Individuals at Clinical High Risk for Psychosis. Int J Neuropsychopharmacol 2017; 21:311-318. [PMID: 29618014 PMCID: PMC5888512 DOI: 10.1093/ijnp/pyx094] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 10/06/2017] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Oxidative stress and glutathione dysregulation have been implicated in the etiology of schizophrenia. To date, most in vivo studies have investigated alterations in cerebral glutathione levels in patients in which the disorder is already established; however, whether oxidative stress actually predates the onset of psychosis remains unknown. In the current study, we investigated cerebral glutathione levels of antipsychotic-naïve individuals at clinical high risk for psychosis. As exploratory analyses, we also investigated the associations between cerebral glutathione levels and peripheral glutathione peroxidase activity and clinical and neuropsychological measures. METHODS Glutathione levels were measured in the medial prefrontal cortex of 30 clinical high risk (n=26 antipsychotic naïve) and 26 healthy volunteers using 3T proton magnetic resonance spectroscopy. Each participant was assessed for glutathione peroxidase activity in plasma and genotyped for the glutamate cysteine ligase catalytic subunit polymorphism. RESULTS No significant differences were observed in glutathione levels between clinical high risk and healthy volunteers in the medial prefrontal cortex (F(1,54)=0.001, P =0.98). There were no significant correlations between cerebral glutathione levels and clinical and neuropsychological measures. Similarly, no significant differences were found in peripheral glutathione peroxidase activity between clinical high risk and healthy volunteers (F(1,37)=0.15, P =0.70). However, in clinical high risk, we observed a significant effect of lifetime history of cannabis use on glutathione peroxidase activity (F(1,23)=7.41, P =0.01). DISCUSSION The lack of significant differences between antipsychotic naïve clinical high risk and healthy volunteers suggests that alterations in glutathione levels in medial prefrontal cortex are not present in the clinical high risk state.
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Affiliation(s)
- Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Ana C Andreazza
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - R Michael Bagby
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Efren Navas
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Isabelle Laksono
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Peter Truong
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Cory Gerritsen
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Ivana Prce
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Napapon Sailasuta
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Correspondence: Romina Mizrahi, MD, PhD, PET Centre, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, Canada M5T 1R8 ()
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Kiang M, Farzan F, Blumberger DM, Kutas M, McKinnon MC, Kansal V, Rajji TK, Daskalakis ZJ. Abnormal self-schema in semantic memory in major depressive disorder: Evidence from event-related brain potentials. Biol Psychol 2017; 126:41-47. [PMID: 28385626 DOI: 10.1016/j.biopsycho.2017.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/03/2017] [Accepted: 04/02/2017] [Indexed: 12/28/2022]
Abstract
An overly negative self-schema is a proposed cognitive mechanism of major depressive disorder (MDD). Self-schema - one's core conception of self, including how strongly one believes one possesses various characteristics - is part of semantic memory (SM), our knowledge about concepts and their relationships. We used the N400 event-related potential (ERP) - elicited by meaningful stimuli, and reduced by greater association of the stimulus with preceding context - to measure association strength between self-concept and positive, negative, and neutral characteristics in SM. ERPs were recorded from MDD patients (n=16) and controls (n=16) who viewed trials comprising a self-referential phrase followed by a positive, negative, or neutral adjective. Participants' task was to indicate via button-press whether or not they felt each adjective described themselves. Controls endorsed more positive adjectives than did MDD patients, but the opposite was true for negative adjectives. Patients had smaller N400s than controls specifically for negative adjectives, suggesting that MDD is associated with stronger than normal functional neural links between self-concept and negative characteristics in SM.
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Affiliation(s)
- Michael Kiang
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
| | - Faranak Farzan
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Daniel M Blumberger
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Marta Kutas
- Department of Cognitive Science and Department of Neurosciences, University of California (San Diego), La Jolla, CA, USA
| | - Margaret C McKinnon
- St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada; Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Vinay Kansal
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Tarek K Rajji
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Zafiris J Daskalakis
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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Abstract
OBJECTIVE Schizophrenia is associated with poor spatial attention. However, although this deficit undermines the perception of target information, it may be helpful for ignoring irrelevant inputs. The present study examined whether event-related brain potential (ERP) indices of visual spatial attention predicted the magnitude of the brain response to interference in schizophrenia. METHOD ERPs were recorded in 16 schizophrenia patients and 20 healthy control participants who had to indicate whether the target E was global or local in compound letter stimuli. The nontarget could be either highly similar to the target (i.e., a global E composed of local Ss and vice versa) and thus produce more interference, or it could be dissimilar (i.e., a global E composed of local Hs and vice versa) and generate less interference. RESULTS Both groups' responses were slowed by interference. Voltage amplitudes of the P1, and of ERP interference effects from 300-500 ms after stimulus onset, were significantly smaller in schizophrenia patients than in healthy participants when the target was global. In patients, larger P1 amplitudes were correlated with larger interference effects and with more severe symptoms of attentional deficits and conceptual disorganization. Schizophrenia participants thus exhibited abnormal ERPs to interference despite normal behavioral performance. CONCLUSIONS Schizophrenia patients likely pay less attention to stimuli in general; however, the impact of this impairment on target detection is compensated by relatively greater inattention to irrelevant components of the stimuli, and this explains why they are not more influenced by interference than healthy participants at the behavioral level. (PsycINFO Database Record
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31
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Nazarov A, Jetly R, McNeely H, Kiang M, Lanius R, McKinnon MC. Role of morality in the experience of guilt and shame within the armed forces. Acta Psychiatr Scand 2015; 132:4-19. [PMID: 25737392 DOI: 10.1111/acps.12406] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/03/2015] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Despite advances in our understanding of mental health issues among military forces, a large proportion of military personnel continue to exhibit deployment-related psychological issues. Recent work has identified symptoms of guilt and shame related to moral injury as contributing significantly to combat-related mental health issues. This systematic scoping review explores the association between morality and symptoms of guilt and shame within military forces. METHOD A search of the literature pertaining to guilt, shame and morality within military samples was conducted. RESULTS Nineteen articles were selected for review. There is strong evidence linking exposure to and the perceived perpetration of moral transgressions with experiences of guilt and shame. Critically, symptoms of guilt and shame were related to adverse mental health outcomes, particularly the onset of post-traumatic stress disorder (PTSD). No studies have explored moral judgment in conjunction with assessments of guilt or moral injury. CONCLUSION These findings have important implications for the prevention and treatment of PTSD-related symptoms in military samples. By measuring moral judgment prior to deployment, it may be possible to predict the likelihood of incurring moral injuries and the development of associated symptoms. Early intervention programmes aimed at ameliorating guilt and shame are required to prevent the long-term development of deployment-related psychological distress.
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Affiliation(s)
- A Nazarov
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, ON, Canada.,Mood Disorders Program, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada
| | - R Jetly
- Department of National Defence, Government of Canada, Ottawa, ON, Canada.,Department of Psychiatry, University of Ottawa, Ottawa, ON, Canada
| | - H McNeely
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, ON, Canada.,Clinical Neuropsychology Service, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada
| | - M Kiang
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - R Lanius
- Department of Psychiatry, University of Western Ontario, London, ON, Canada
| | - M C McKinnon
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, ON, Canada.,Mood Disorders Program, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada.,Homewood Research Institute, Guelph, ON, Canada
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MacDougall AG, McKinnon MC, Herdman KA, King MJ, Kiang M. The relationship between insight and autobiographical memory for emotional events in schizophrenia. Psychiatry Res 2015; 226:392-5. [PMID: 25623015 DOI: 10.1016/j.psychres.2014.12.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/07/2014] [Accepted: 12/29/2014] [Indexed: 11/16/2022]
Abstract
The relation of episodic and semantic memory for emotional- (positive, negative) and neutral-valenced autobiographical events to illness insight was examined in individuals with schizophrenia. Reduced recall of episodic details for negative events was significantly associated with impaired awareness of having a past mental disorder and its social consequences. Deficits in episodic memory for negative autobiographical events may underlie impaired insight in schizophrenia.
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Affiliation(s)
- Arlene G MacDougall
- Department of Psychiatry, Western University, London Health Sciences Centre-Victoria Hospital, 800 Commissioner's Road East, London, ON, Canada N6A 5W9; Department of Psychiatry and Behavioural Neurosciences, McMaster University, St. Joseph׳s Healthcare Hamilton, West 5th Campus, 100 West 5th, Hamilton, ON, Canada L8N 3K7.
| | - Margaret C McKinnon
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, St. Joseph׳s Healthcare Hamilton, West 5th Campus, 100 West 5th, Hamilton, ON, Canada L8N 3K7; Homewood Research Institute, Homewood Health Centre, 150 Delhi Street, Guelph, ON, Canada N1E 6K9.
| | - Katherine A Herdman
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, St. Joseph׳s Healthcare Hamilton, West 5th Campus, 100 West 5th, Hamilton, ON, Canada L8N 3K7.
| | - Matthew J King
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, St. Joseph׳s Healthcare Hamilton, West 5th Campus, 100 West 5th, Hamilton, ON, Canada L8N 3K7.
| | - Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, St. Joseph׳s Healthcare Hamilton, West 5th Campus, 100 West 5th, Hamilton, ON, Canada L8N 3K7; Department of Psychiatry, University of Toronto, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, Canada M5T 1R8.
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Kiang M, Christensen BK, Zipursky RB. Event-related brain potential study of semantic priming in unaffected first-degree relatives of schizophrenia patients. Schizophr Res 2014; 153:78-86. [PMID: 24451397 DOI: 10.1016/j.schres.2014.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 12/25/2013] [Accepted: 01/02/2014] [Indexed: 10/25/2022]
Abstract
Schizophrenia is associated with abnormalities in using meaningful stimuli to activate or prime related concepts in semantic long-term memory. A neurophysiological index of this activation is the N400, an event-related brain potential (ERP) waveform elicited by meaningful stimuli, which is normally reduced (made less negative) by relatedness between the eliciting stimulus and preceding ones (N400 semantic priming). Schizophrenia patients exhibit N400 semantic priming deficits, suggesting impairment in using meaningful context to activate related concepts. To address whether this abnormality is a trait-like marker of liability to schizophrenia or, alternatively, a biomarker of the illness itself, we tested for its presence in schizophrenia patients' unaffected biological relatives. We recorded ERPs from 12 unaffected first-degree relatives of schizophrenia patients, 12 schizophrenia patients, and 12 normal control participants (NCPs) who viewed prime words each followed at 300- or 750-ms stimulus-onset asynchrony (SOA) by an unrelated or related target word, or a nonword, in a lexical-decision task. As expected, across SOAs, NCPs exhibited smaller (less negative) N400 amplitudes for related versus unrelated targets. The same pattern held in relatives, whose N400 amplitudes for related and unrelated targets did not differ from NCPs'. In contrast, consistent with previous results, schizophrenia patients exhibited larger N400 amplitudes than NCPs (and relatives) for related targets, such that patients' N400 amplitudes for related and unrelated targets did not differ. N400 amplitudes for unrelated targets did not differ between the three groups. Thus, N400 semantic priming deficits in a visual word-pair paradigm may be an illness biomarker for schizophrenia.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada; St. Joseph's Healthcare, Hamilton, Ontario, Canada.
| | - Bruce K Christensen
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada; St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Robert B Zipursky
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada; St. Joseph's Healthcare, Hamilton, Ontario, Canada
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Kiang M, Christensen BK, Streiner DL, Roy C, Patriciu I, Zipursky RB. Association of abnormal semantic processing with delusion-like ideation in frequent cannabis users: an electrophysiological study. Psychopharmacology (Berl) 2013; 225:95-104. [PMID: 22782461 PMCID: PMC5045303 DOI: 10.1007/s00213-012-2800-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 06/27/2012] [Indexed: 01/23/2023]
Abstract
RATIONALE Frequent cannabis use is a risk marker for schizophrenia and delusions, but the neurocognitive mechanisms of this relationship remain unclear. OBJECTIVES We sought evidence that cannabis users have deficits in processing relationships between meaningful stimuli, similar to abnormalities reported in schizophrenia, and that these deficits are associated with delusion-like ideation. We used the N400 event-related brain potential (ERP) waveform as a neurophysiological probe of activation of concepts in semantic memory. We hypothesized that cannabis users would exhibit larger (more negative) than normal N400 amplitudes in response to stimuli meaningfully related to a preceding prime-reflecting deficient activation of concepts related to the prime. We further hypothesized that the magnitude of this abnormality would correlate with severity of delusion-like ideation. METHODS We recorded ERPs in 24 frequent cannabis users and 24 non-using comparison participants who viewed prime words followed by targets which were either words related or unrelated to the prime or pronounceable nonwords. The participants' task was to indicate whether the target was a word. Delusion-like ideation was measured via the Schizotypal Personality Questionnaire. RESULTS Contrary to our hypothesis, cannabis users exhibited smaller than normal N400s to both related and unrelated targets. These abnormalities correlated with delusion-like ideation in cannabis users only. CONCLUSIONS The results are consistent with a generalized abnormality of activation within semantic memory neural networks in cannabis users. Further research is needed to investigate whether such an abnormality plays a role in the development of delusion-like ideation in cannabis users.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
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Kiang M, Patriciu I, Roy C, Christensen BK, Zipursky RB. Test-retest reliability and stability of N400 effects in a word-pair semantic priming paradigm. Clin Neurophysiol 2012; 124:667-74. [PMID: 23122708 DOI: 10.1016/j.clinph.2012.09.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 08/31/2012] [Accepted: 09/09/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Elicited by any meaningful stimulus, the N400 event-related potential (ERP) component is reduced when the stimulus is related to a preceding one. This N400 semantic priming effect has been used to probe abnormal semantic relationship processing in clinical disorders, and suggested as a possible biomarker for treatment studies. Validating N400 semantic priming effects as a clinical biomarker requires characterizing their test-retest reliability. METHODS We assessed test-retest reliability of N400 semantic priming in 16 healthy adults who viewed the same related and unrelated prime-target word pairs in two sessions one week apart. RESULTS As expected, N400 amplitudes were smaller for related versus unrelated targets across sessions. N400 priming effects (amplitude differences between unrelated and related targets) were highly correlated across sessions (r=0.85, P<0.0001), but smaller in the second session due to larger N400s to related targets. CONCLUSIONS N400 priming effects have high reliability over a one-week interval. They may decrease with repeat testing, possibly because of motivational changes. SIGNIFICANCE Use of N400 priming effects in treatment studies should account for possible magnitude decreases with repeat testing. Further research is needed to delineate N400 priming effects' test-retest reliability and stability in different age and clinical groups, and with different stimulus types.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada.
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Bixel K, Hur HC, Merport Modest A, Kiang M, Singer S. Impact of Perceptions of Patient Safety on Planning and Implementation of Surgical Safety Checklists. J Minim Invasive Gynecol 2012. [DOI: 10.1016/j.jmig.2012.08.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kiang M, Christensen BK, Kutas M, Zipursky RB. Electrophysiological evidence for primary semantic memory functional organization deficits in schizophrenia. Psychiatry Res 2012; 196:171-80. [PMID: 22460130 PMCID: PMC4075227 DOI: 10.1016/j.psychres.2012.02.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 10/28/2011] [Accepted: 02/21/2012] [Indexed: 11/29/2022]
Abstract
N400, an event-related brain potential (ERP) waveform elicited by meaningful stimuli, is normally reduced by stimulus repetition (N400 repetition priming), and relatedness between the eliciting stimulus and preceding ones (relatedness priming). Schizophrenia patients' N400 relatedness priming deficits suggest impairment in using meaningful prime stimuli to facilitate processing of related concepts in semantic memory. To examine whether this deficiency arises from difficulty activating the prime concept per se, as indexed by reduced N400 repetition priming; or from impaired functional connections among concepts in semantic memory, as reflected by reduced relatedness priming but normal repetition priming; we recorded ERPs from 16 schizophrenia patients and 16 controls who viewed prime words each followed at 300- or 750-ms stimulus-onset asynchrony (SOA) by an unrelated, related or repeated target word, or a nonword, in a lexical-decision task. In both groups, N400s were largest (most negative) for unrelated, intermediate for related, and smallest for repeated targets. Schizophrenia patients exhibited subnormal N400 relatedness priming at the 300-ms SOA, but normal repetition priming at both SOAs, suggesting that their impairment in using prime words to activate related concepts results from abnormal functional connections among concepts within semantic memory, rather than inability to activate the prime concept itself.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
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Kiang M, Christensen BK, Zipursky RB. Depth-of-processing effects on semantic activation deficits in schizophrenia: an electrophysiological investigation. Schizophr Res 2011; 133:91-8. [PMID: 21868201 DOI: 10.1016/j.schres.2011.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 07/29/2011] [Accepted: 08/01/2011] [Indexed: 11/16/2022]
Abstract
N400, an event-related brain potential (ERP) waveform elicited by meaningful stimuli, is normally reduced (made less negative) by relatedness between the eliciting stimulus and preceding ones (N400 semantic priming). Schizophrenia patients' N400 semantic priming deficits suggest impairment in using meaningful context to activate related concepts in semantic memory. We aimed to examine the degree to which this impairment can be ameliorated by task instructions that more explicitly require processing of stimulus meaning. We recorded ERPs from 16 schizophrenia patients and 16 controls who viewed prime words each followed at 750-ms stimulus-onset asynchrony by an unrelated or related target word, or a nonword, in a non-semantic task (indicating whether a letter occurred in the target) compared to an explicit semantic task (judging prime-target relatedness). Consistent with previous work, controls exhibited greater N400 semantic priming (larger amplitude reductions for related versus unrelated targets) in the semantic task than in the orthographic task. Schizophrenia patients showed this same pattern, although their N400 semantic priming effects were smaller than controls' across tasks. Nevertheless, patients' priming effects increased as much as did controls' from the orthographic to the semantic task. Thus, connections among related concepts in schizophrenia patients' semantic memory appear grossly intact, such that, given a meaningful stimulus, they can make use of explicit cues to activate related concepts at a neurophysiological level, although their ability to do so remains less than normal. These data provide support for further research on semantic-cueing strategies for cognitive remediation of verbal memory in schizophrenia.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Ontario, Canada L8S 4K1
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Apiquian R, Fresán A, Muñoz-Delgado J, Kiang M, Ulloa RE, Kapur S. Variations of rest – activity rhythm and sleep – wake in schizophrenic patients versus healthy subjects: An actigraphic comparative study. BIOL RHYTHM RES 2008. [DOI: 10.1080/09291010701318253] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
OBJECTIVE Following a meaningful prime stimulus, schizophrenia patients have been hypothesized to exhibit impaired neurophysiological activation of related concepts in general, and/or supranormal activation of weakly related concepts in particular, within semantic memory. The former abnormality may occur at longer intervals, and the latter at shorter intervals, after the prime. The authors tested these hypotheses using the N400 event-related brain potential as a probe of activation of concepts in semantic memory. METHOD Event-related potentials were recorded in 16 schizophrenia patients and 16 normal comparison subjects who viewed prime words, each followed by a target that was a directly (strongly) related word, indirectly (weakly) related word, unrelated word, or nonword, in a lexical-decision task. Equal numbers of each target type were presented 300 and 750 msec after the prime. RESULTS In the comparison subjects, N400 amplitude was largest (most negative) following unrelated targets, intermediate after indirectly related targets, and smallest after directly related targets. In contrast, patients' N400 amplitudes did not differ between these target types, reflecting larger amplitudes following both directly and indirectly related targets in patients than in comparison subjects; these findings held regardless of prime-to-target stimulus-onset asynchrony. Within patients, at the longer asynchrony, larger N400 amplitudes after directly and indirectly related targets correlated with positive psychotic symptoms. CONCLUSIONS The results suggest hypoactivation of strongly and weakly related concepts following a meaningful stimulus, regardless of interval, in schizophrenia. An N400 index of this hypoactivation correlated with severity of delusions, suggesting a role for abnormal semantic processing in their pathogenesis.
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Affiliation(s)
- Michael Kiang
- University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0515, USA.
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Kiang M, Light GA, Prugh J, Coulson S, Braff DL, Kutas M. Cognitive, neurophysiological, and functional correlates of proverb interpretation abnormalities in schizophrenia. J Int Neuropsychol Soc 2007; 13:653-63. [PMID: 17521483 DOI: 10.1017/s1355617707070816] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 01/23/2007] [Accepted: 01/23/2007] [Indexed: 12/21/2022]
Abstract
A hallmark of schizophrenia is impaired proverb interpretation, which could be due to: (1) aberrant activation of disorganized semantic associations, or (2) working memory (WM) deficits. We assessed 18 schizophrenia patients and 18 normal control participants on proverb interpretation, and evaluated these two hypotheses by examining within patients the correlations of proverb interpretation with disorganized symptoms and auditory WM, respectively. Secondarily, we also explored the relationships between proverb interpretation and a spectrum of cognitive functions including auditory sensory-memory encoding (as indexed by the mismatch negativity (MMN) event-related brain potential (ERP)); executive function; and social/occupational function. As expected, schizophrenia patients produced less accurate and less abstract descriptions of proverbs than did controls. These proverb interpretation difficulties in patients were not significantly correlated with disorganization or other symptom factors, but were significantly correlated (p < .05) with WM impairment, as well as with impairments in sensory-memory encoding, executive function, and social/occupational function. These results offer no support for disorganized associations in abnormal proverb interpretation in schizophrenia, but implicate WM deficits, perhaps as a part of a syndrome related to generalized frontal cortical dysfunction.
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Affiliation(s)
- Michael Kiang
- Department of Cognitive Science, University of California--San Diego, La Jolla, California 92093, USA.
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Kiang M, Kutas M, Light GA, Braff DL. Electrophysiological insights into conceptual disorganization in schizophrenia. Schizophr Res 2007; 92:225-36. [PMID: 17383161 PMCID: PMC3974604 DOI: 10.1016/j.schres.2007.02.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 01/31/2007] [Accepted: 02/02/2007] [Indexed: 11/21/2022]
Abstract
Disorganized speech, or thought disorder, in schizophrenia may reflect abnormal processing of meaningful concepts. To examine whether schizophrenia involves abnormalities in how a meaningful context influences processing of concepts strongly, weakly, or not related to it, we used the N400, an event-related brain potential (ERP) index of semantic relatedness. ERPs were recorded from schizophrenia patients (n=18) and normal controls (n=18) while they viewed category definitions (e.g., a type of fruit), each followed by a target word that was either a high-typicality category exemplar (apple), low-typicality exemplar (cherry), or non-exemplar (clamp). Participants' task was to indicate via button-press whether or not the target belonged to the category. In both patients and controls, N400 amplitude was largest (most negative) for non-exemplars, intermediate for low-typicality exemplars, and smallest (least negative) for high-typicality exemplars. Compared to controls, patients showed a trend toward reduced N400 amplitude differences between non-exemplars and low-typicality exemplars. Most importantly, within patients, reduced N400 amplitude differences between high- and low-typicality exemplars were correlated with psychotic symptoms. This association of an N400 index of semantic processing with psychotic symptoms suggests that psychosis in schizophrenia may be associated with greater similarity in how concepts strongly and weakly meaningfully related to their context are processed.
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Affiliation(s)
- Michael Kiang
- Department of Cognitive Science, University of California-San Diego, 9500 Gilman Dr., Mail Code 0515, La Jolla, CA 92093-0515, USA.
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Abstract
Existing hypotheses about semantic processing in schizophrenia and schizotypy suggest that both conditions are associated with a less than normal difference in the degree to which some concept activates the mental representation of other concepts that are strongly versus weakly related to it in meaning. To seek further evidence for this, we examined response typicality on the Category Fluency Test (CFT) as a function of schizotypy. Individuals from a non-clinical population verbally generated as many exemplars as they could in 1 min for each of four categories (fruits, four-footed animals, articles of clothing, vehicles). Participants subsequently completed the Schizotypal Personality Questionnaire (SPQ). SPQ score was not significantly correlated with the total number of responses generated for any of the categories. Individuals with higher (as opposed to lower) SPQ scores, however, generated more atypical members of the fruit category both in their initial responses and overall (as indexed by the average ratio of each response's ordinal position to its position in population typicality norms). These results support the hypothesis that semantic memory organization in non-clinical individuals with higher schizotypy is functionally altered.
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Affiliation(s)
- Michael Kiang
- Department of Cognitive Science, University of California, San Diego, Mail Code 0515, 9500 Gilman Dr., La Jolla, CA 92093-0515, USA.
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Mizrahi R, Kiang M, Mamo DC, Arenovich T, Bagby RM, Zipursky RB, Kapur S. The selective effect of antipsychotics on the different dimensions of the experience of psychosis in schizophrenia spectrum disorders. Schizophr Res 2006; 88:111-8. [PMID: 16956747 DOI: 10.1016/j.schres.2006.07.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 07/04/2006] [Accepted: 07/10/2006] [Indexed: 10/24/2022]
Abstract
While most standard symptom scales regard the 'psychotic' or 'positive' dimension of schizophrenia as a single factor, several lines of evidence suggest that psychosis itself is a multidimensional phenomenon. The foregoing literature suggested at least five distinct dimensions to psychosis; to test this, we developed, validated and applied an instrument to measure these dimensions and then applied it to examine the effect of antipsychotics on the different dimensions of the psychotic experience. The Dimensions of Psychosis Instrument (DIPI) was administered to 91 psychotic patients with schizophrenia spectrum disorders and a confirmatory factor analyses (CFA) was carried out to examine the five dimensions: cognitive preoccupation (CP) with the psychotic experience; emotional involvement (EM); behavioural impact (BI) of the experience; conviction (CO) in it; emotional; and external perspective (EP) about the experience. In a separate cohort of 17 prospectively treated patients, the impact of antipsychotics on these dimensions was assessed. BI showed the greatest improvement (32%) at 2 weeks, while CP and emotional improved somewhat less (22% and 14%, respectively). Improvement in CO was limited (6%) while EP showed no change. These results suggest that over the first few weeks of treatment, antipsychotics rapidly reduce the behavioural impact of the principal psychotic symptom and decrease cognitive and emotional preoccupation with it, without greatly altering the patients' conviction in or perspective about their psychotic experience.
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Affiliation(s)
- Romina Mizrahi
- CAMH, and Department of Psychiatry, Faculty of Medicine, University of Toronto, Ontario, Canada
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Kiang M, Kutas M. Association of schizotypy with semantic processing differences: an event-related brain potential study. Schizophr Res 2005; 77:329-42. [PMID: 15919182 DOI: 10.1016/j.schres.2005.03.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 03/21/2005] [Accepted: 03/24/2005] [Indexed: 10/25/2022]
Abstract
Disorganized speech in both schizophrenia and schizotypy has been hypothesized to result from abnormalities in how concepts activate one another in semantic memory. To study whether schizotypy is associated with differences in how categories activate their exemplars, we examined the N400 component of the event-related brain potential (ERP) elicited during a category-verification task. ERPs were recorded in young adults from the general population while they viewed category definitions each followed by a target that was either a high-typicality exemplar, low-typicality exemplar, or non-exemplar; participants' task was to indicate whether or not the target belonged to the category. Schizotypy was assessed via the Schizotypal Personality Questionnaire (SPQ). Overall, N400 amplitude was largest for non-exemplars, smallest for high-typicality exemplars, and intermediate for low-typicality exemplars. SPQ score was associated with decreased N400 amplitude to non-exemplars, and increased amplitude to both types of exemplars. SPQ score was negatively correlated with the N400 amplitude difference between non-exemplars and both low- and high-typicality exemplars, but was not correlated with the amplitude difference between low- and high-typicality exemplars. N400 amplitude differences between non-exemplars and both types of exemplars were correlated with the SPQ Interpersonal factor, but not the Disorganized factor. The results are consistent with an association of schizotypy with decreased use of context to activate related items and inhibit unrelated items.
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Affiliation(s)
- Michael Kiang
- Department of Cognitive Science, University of California-San Diego, 9500 Gilman Dr., Mail Code 0515, La Jolla, CA 92093-0515, USA.
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Abstract
Apathy is considered one of the negative symptoms of schizophrenia, but its natural history and relationship to other clinical characteristics have not been systematically studied. The purpose of this cross-sectional study was to measure the level of apathy in schizophrenia and its relation to other symptoms and functional outcome. Twenty-eight patients with schizophrenia, and receiving antipsychotic treatment, were assessed with the Apathy Evaluation Scale (AES). The mean level of apathy of patients with schizophrenia, as rated by the AES, was significantly higher than that of matched healthy control subjects. In the patients, apathy was not significantly correlated with positive symptoms or depressive symptoms. It was significantly correlated with the item "emotional withdrawal" on the negative subscale of the Positive and Negative Syndrome Scale (PANSS), but was not correlated with the overall negative subscale score. Apathy was more highly associated with functional outcome than were other symptom measures, and it was independently associated with functional outcome above and beyond other negative symptoms. It was not associated with observed interest in playing a video game or performance on a simulated clerical task.
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Affiliation(s)
- Michael Kiang
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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Kiang M, Daskalakis ZJ, Christensen BK, Remington G, Kapur S. Actigraphic measurement of the effects of single-dose haloperidol and olanzapine on spontaneous motor activity in normal subjects. J Psychiatry Neurosci 2003; 28:293-9. [PMID: 12921224 PMCID: PMC165794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
OBJECTIVE To quantitatively examine the effects of haloperidol and olanzapine on spontaneous motor activity in normal subjects. DESIGN Randomized, double-blind, placebo-controlled medication study. PARTICIPANTS Normal volunteers (n = 30). INTERVENTIONS Subjects received 1 dose of either haloperidol 2 mg (n = 9), olanzapine 10 mg (n = 10) or placebo (n = 10) and were admitted to hospital for the next 24 hours. OUTCOME MEASURES Subjects wore an actigraphic monitor, which recorded movement in 15-second epochs. The Simpson-Angus Extrapyramidal Side Effect Scale (SAS) and the Barnes Akathisia Scale (BAS) were administered before and 7 and 24 hours after medication was given. RESULTS Compared with placebo, total motor activity was decreased by 41% with olanzapine (p = 0.004) and by 12% with haloperidol (NS). There were significantly more epochs with zero movement with olanzapine than with haloperidol or placebo. For non-zero epochs, the mean activity count and the distribution of activity counts did not differ significantly among groups. There were no positive findings on the SAS or the BAS. CONCLUSIONS Olanzapine decreased total motor activity by increasing the amount of time during which subjects were immobile, rather than by affecting the magnitude of movement during periods in which there was activity. This effect occurred at a dose of olanzapine low enough not to cause clinically observed extrapyramidal side effects. Our results suggest that actigraphy is useful as a sensitive, noninvasive tool for measuring the effect of antipsychotics on spontaneous motor activity.
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Affiliation(s)
- Michael Kiang
- Schizophrenia Division, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ont
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Holmes AC, Judd FK, Yeatman R, Lloyd JH, Dakis J, Cairns F, Kiang M, Kerr L, McKinnon J. A 12-month follow up of the implementation of clinical indicators in a consultation-liaison service. Aust N Z J Psychiatry 2001; 35:236-9. [PMID: 11284907 DOI: 10.1046/j.1440-1614.2001.00878.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES This paper reviews the use of clinical indicators in a consultation-liaison (C-L) service over a 12-month period at the Royal Melbourne Hospital, Melbourne, Australia. METHOD Clinical indicators and C-L data were collected during the 1999 calendar year. A review of the process was conducted during and after completion of the 12-month period. RESULTS The system was found to be practical and useful. The use of clinical indicators led to the identification of problems and stimulated effective interventions. The use of the clinical indicators was associated with improvement in communication between C-L staff, parent units and practitioners providing follow-up. CONCLUSIONS The implementation of a database and clinical indicators was a useful addition to the C-L service. The use of clinical indicators was effective in improving clinical performance. These benefits need to be balanced against increased administrative burden.
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Affiliation(s)
- A C Holmes
- Department of Psychiatry, Royal Melboourne Hospital, Universiity of Melbourne, C/- Post Office, The Royal Melbourne Hospital, Mel-bourne, Victoria 3050, Australia.
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