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Bielecki M, Tyburski E, Plichta P, Samochowiec J, Kucharska-Mazur J, Podwalski P, Rek-Owodziń K, Waszczuk K, Sagan L, Michalczyk A, Rudkowski K, Karabanowicz E, Świątkowska K, Misiak B, Bąba-Kubiś A, Mak M. Impulsivity and inhibitory control in deficit and non-deficit schizophrenia. BMC Psychiatry 2024; 24:473. [PMID: 38937731 PMCID: PMC11209995 DOI: 10.1186/s12888-024-05918-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 06/17/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND There is conflicting evidence on impulsivity and its potential relationship with inhibitory control in schizophrenia. This study therefore aimed to identify differences in impulsivity and cognitive and motor inhibition between patients with deficit (DS) and non-deficit (NDS) schizophrenia and healthy controls (HC). We also explored the relationships between impulsivity and different dimensions of inhibitory control in all studied groups. METHODS The sample comprised 28 DS patients, 45 NDS patients, and 39 age-matched HC. A neuropsychological battery was used. RESULTS DS patients scored lower in venturesomeness, while those with NDS scored higher in impulsiveness compared to HC. In addition, both groups of patients scored higher on measures of cognitive and motor inhibition, including those relatively independent of information processing speed (although the results were slightly different after adjusting for IQ and/or years of education). Correlations between impulsivity and cognitive inhibition emerged in DS patients, while links between impulsivity and motor inhibition were observed in HC. CONCLUSIONS Our results suggest the presence of deficits in experimentally assessed inhibitory control in schizophrenia patients, with predominant impulsivity in the NDS population. In addition, impulsivity may affect the cognitive control of inhibition in deficit schizophrenia. Nevertheless, due to the preliminary nature of these findings, they require further empirical verification in future research.
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Affiliation(s)
- Maksymilian Bielecki
- Department of Health Psychology, Pomeranian Medical University in Szczecin, Broniewskiego 26 str, Szczecin, 71-457, Poland
| | - Ernest Tyburski
- Department of Health Psychology, Pomeranian Medical University in Szczecin, Broniewskiego 26 str, Szczecin, 71-457, Poland.
| | - Piotr Plichta
- Department of Health Psychology, Pomeranian Medical University in Szczecin, Broniewskiego 26 str, Szczecin, 71-457, Poland
| | - Jerzy Samochowiec
- Department of Psychiatry, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | | | - Piotr Podwalski
- Department of Psychiatry, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Katarzyna Rek-Owodziń
- Department of Health Psychology, Pomeranian Medical University in Szczecin, Broniewskiego 26 str, Szczecin, 71-457, Poland
| | - Katarzyna Waszczuk
- Department of Psychiatry, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Leszek Sagan
- Department of Neurosurgery, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Anna Michalczyk
- Department of Psychiatry, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Krzysztof Rudkowski
- Department of Psychiatry, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Ewa Karabanowicz
- Institute of Psychology, University of Szczecin, Szczecin, Poland
| | - Katarzyna Świątkowska
- Department of Health Psychology, Pomeranian Medical University in Szczecin, Broniewskiego 26 str, Szczecin, 71-457, Poland
| | - Błażej Misiak
- Department of Consultation Psychiatry and Neuroscience, Wrocław Medical University, Wrocław, Poland
| | - Agata Bąba-Kubiś
- Department of Psychiatry, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Monika Mak
- Department of Health Psychology, Pomeranian Medical University in Szczecin, Broniewskiego 26 str, Szczecin, 71-457, Poland
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2
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Faden J, Citrome L. A systematic review of clozapine for aggression and violence in patients with schizophrenia or schizoaffective disorder. Schizophr Res 2024; 268:265-281. [PMID: 38290941 DOI: 10.1016/j.schres.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 10/26/2023] [Accepted: 11/19/2023] [Indexed: 02/01/2024]
Abstract
Although uncommon, the risk of aggression and violence is greater in people with schizophrenia than in the general population. Clozapine is the "gold standard" pharmacologic treatment for the management of persistent agitation and aggression in people with schizophrenia and is consistently recommended by guidelines and reviews for this purpose. Although clozapine is indicated for treatment-resistant schizophrenia based on its superior efficacy, studies have proposed that clozapine may have specific properties that ameliorate aggression and hostility that are distinct from its antipsychotic effects. A literature review was conducted on June 3, 2023, using the US National Library of Medicine's PubMed resource to identify articles focusing on clozapine for the treatment of aggression, violence, and/or hostility in patients with schizophrenia or schizoaffective disorder. The majority of evidence, including from randomized control trials, supports the utilization of clozapine as maintenance treatment for persistent aggressive behavior in patients with schizophrenia, and supports that its anti-aggressive effects may be independent from its antipsychotic properties (e.g. - treatment of hallucinations and delusions). Future randomized control studies evaluating clozapine and clozapine serum levels with aggression as the primary outcome would be of benefit.
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Affiliation(s)
- Justin Faden
- Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States of America.
| | - Leslie Citrome
- New York Medical College, Valhalla, NY, United States of America
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3
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Cubello J, Marvin E, Conrad K, Merrill AK, George JV, Welle K, Jackson BP, Chalupa D, Oberdörster G, Sobolewski M, Cory-Slechta DA. The contributions of neonatal inhalation of copper to air pollution-induced neurodevelopmental outcomes in mice. Neurotoxicology 2024; 100:55-71. [PMID: 38081392 PMCID: PMC10842733 DOI: 10.1016/j.neuro.2023.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
Exposures to ambient ultrafine particle (UFP) air pollution (AP) during the early postnatal period in mice (equivalent to human third trimester brain development) produce male-biased changes in brain structure, including ventriculomegaly, reduced brain myelination, alterations in neurotransmitters and glial activation, as well as impulsive-like behavioral characteristics, all of which are also features characteristic of male-biased neurodevelopmental disorders (NDDs). The purpose of this study was to ascertain the extent to which inhaled Cu, a common contaminant of AP that is also dysregulated across multiple NDDs, might contribute to these phenotypes. For this purpose, C57BL/6J mice were exposed from postnatal days 4-7 and 10-13 for 4 hr/day to inhaled copper oxide (CuxOy) nanoparticles at an environmentally relevant concentration averaging 171.9 ng/m3. Changes in brain metal homeostasis and neurotransmitter levels were determined following termination of exposure (postnatal day 14), while behavioral changes were assessed in adulthood. CuxOy inhalation modified cortical metal homeostasis and produced male-biased disruption of striatal neurotransmitters, with marked increases in dopaminergic function, as well as excitatory/inhibitory imbalance and reductions in serotonergic function. Impulsive-like behaviors in a fixed ratio (FR) waiting-for-reward schedule and a fixed interval (FI) schedule of food reward occurred in both sexes, but more prominently in males, effects which could not be attributed to altered locomotor activity or short-term memory. Inhaled Cu as from AP exposures, at environmentally relevant levels experienced during development, may contribute to impaired brain function, as shown by its ability to disrupt brain metal homeostasis and striatal neurotransmission. In addition, its ability to evoke impulsive-like behavior, particularly in male offspring, may be related to striatal dopaminergic dysfunction that is known to mediate such behaviors. As such, regulation of air Cu levels may be protective of public health.
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Affiliation(s)
- Janine Cubello
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
| | - Elena Marvin
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Katherine Conrad
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Alyssa K Merrill
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jithin V George
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Kevin Welle
- Proteomics Core, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Brian P Jackson
- Department of Earth Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - David Chalupa
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Günter Oberdörster
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Marissa Sobolewski
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
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Vanova M, Ettinger U, Aldridge-Waddon L, Jennings B, Norbury R, Kumari V. Positive schizotypy and Motor Impulsivity correlate with response aberrations in ventral attention network during inhibitory control. Cortex 2023; 169:235-248. [PMID: 37952300 DOI: 10.1016/j.cortex.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/17/2023] [Accepted: 08/25/2023] [Indexed: 11/14/2023]
Abstract
Inhibitory control (IC) aberrations are present in various psychopathologies, including schizophrenia spectrum and personality disorders, especially in association with antisocial or violent behaviour. We investigated behavioural and neural associations between IC and psychopathology-related traits of schizotypy [Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE)], psychopathy [Triarchic Psychopathy Measure (TriPM)], and impulsivity [Barratt Impulsiveness Scale (BIS-11)], using a novel Go/No-Go Task (GNG) featuring human avatars in 78 healthy adults (25 males, 53 females; mean age = 25.96 years, SD = 9.85) and whole-brain functional magnetic resonance imaging (fMRI) in a separate sample of 22 right-handed healthy individuals (7 males, 15 females; mean age = 24.13 years, SD = 5.40). Behaviourally, O-LIFE Impulsive Nonconformity (impulsive, anti-social, and eccentric behaviour) significantly predicted 16 % of variance in false alarms (FAs). O-LIFE Unusual Experiences (positive schizotypy) and BIS-11 Motor Impulsivity predicted 15 % of d prime (d') (sensitivity index) for the fastest (400 ms) GNG trials. When examined using fMRI, higher BIS-11 Motor Impulsivity uniquely, and also together with Unusual Experiences, was associated with lower activity in the left lingual gyrus during successful inhibition (correct No-Go over baseline). Additionally, higher Impulsive Nonconformity was associated with lower activity in the caudate nucleus and anterior cingulate during No-Go compared to Go stimuli reactions. Positive schizotypy, motor, and antisocial-schizotypal impulsivity correlate with some common but mostly distinct neural activation patterns during response inhibition in areas within or associated with the ventral attention network.
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Affiliation(s)
- Martina Vanova
- Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Dementia Research Centre, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.
| | | | - Luke Aldridge-Waddon
- Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom
| | - Ben Jennings
- Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom
| | - Ray Norbury
- Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom
| | - Veena Kumari
- Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom.
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Calli SY, Fidan YS, Bestepe EE, Izci F. The Relationship Between Suicidal Behavior, Neurocognitive Functions, and Insight in Patients with Schizophrenia. PSYCHIAT CLIN PSYCH 2023; 33:126-133. [PMID: 38765924 PMCID: PMC11082585 DOI: 10.5152/pcp.2023.22530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 04/23/2023] [Indexed: 05/22/2024] Open
Abstract
Background In schizophrenia, the relationship between suicide and cognition is unclear. We aimed to assess cognitive functions and insight in schizophrenia patients with and without suicide attempts. Methods In our study consisting of 77 patients, 36 of the patients had attempted suicide at least once in their lives and the remaining 41 had never attempted suicide. Sociodemographic data scale, Beck Cognitive Insight Scale, and Cambridge Neurophysiological Assessment Battery were applied. Results In this study, patients with schizophrenia who attempted suicide had higher Beck Cognitive Insight Scale self-reflectiveness scores (P = .004), lower Beck Cognitive Insight Scale self-certainty scores (P = .040), and higher Beck Cognitive Insight Scale total score (P = .004). Delay aversion (P = .003) and risk-taking scores (P = .044) of Cambridge Neurophysiological Assessment Battery Cambridge gambling task were higher in patients who attempted suicide. In logistic regression analysis, as independent factors, the number of hospitalizations increased the risk of suicide 1.5 times per hospitalization (P = .021), Cambridge gambling task delay aversion increased the risk of suicide 8.4 times per score (P = .044), and the Beck Cognitive Insight Scale self-certainty score was shown as the factor that decreased the risk of suicide by 0.78 times (P = .024). Conclusion The causes of suicide attempts in schizophrenia still preserve its uncertainty. Our results proposed a statistically significant relationship between cognitive insight and increased suicide attempts. This study also sustains that cognitive impulsivity is associated with suicidal behavior in patients with schizophrenia.
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Affiliation(s)
- Sumeyye Yasemin Calli
- Erenköy Mental and Nervous Diseases Training and Research Hospital, Istanbul, Turkey
| | - Yagmur Sever Fidan
- Erenköy Mental and Nervous Diseases Training and Research Hospital, Istanbul, Turkey
| | - Engin Emrem Bestepe
- Erenköy Mental and Nervous Diseases Training and Research Hospital, Istanbul, Turkey
| | - Filiz Izci
- Erenköy Mental and Nervous Diseases Training and Research Hospital, Istanbul, Turkey
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Núñez C, García-Alix A, Arca G, Agut T, Carreras N, Portella MJ, Stephan-Otto C. Breastfeeding duration is associated with larger cortical gray matter volumes in children from the ABCD study. J Child Psychol Psychiatry 2023. [PMID: 36946606 DOI: 10.1111/jcpp.13790] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/09/2023] [Indexed: 03/23/2023]
Abstract
BACKGROUND Despite the numerous studies in favor of breastfeeding for its benefits in cognition and mental health, the long-term effects of breastfeeding on brain structure are still largely unknown. Our main objective was to study the relationship between breastfeeding duration and cerebral gray matter volumes. We also explored the potential mediatory role of brain volumes on behavior. METHODS We analyzed 7,860 magnetic resonance images of children 9-11 years of age from the Adolescent Brain Cognitive Development (ABCD) dataset in order to study the relationship between breastfeeding duration and cerebral gray matter volumes. We also obtained several behavioral data (cognition, behavioral problems, prodromal psychotic experiences, prosociality, impulsivity) to explore the potential mediatory role of brain volumes on behavior. RESULTS In the 7,860 children analyzed (median age = 9 years and 11 months; 49.9% female), whole-brain voxel-based morphometry analyses revealed an association mainly between breastfeeding duration and larger bilateral volumes of the pars orbitalis and the lateral orbitofrontal cortex. In particular, the association with the left pars orbitalis and the left lateral orbitofrontal cortex proved to be very robust to the addition of potentially confounding covariates, random selection of siblings, and splitting the sample in two. The volume of the left pars orbitalis and the left lateral orbitofrontal cortex appeared to mediate the relationship between breastfeeding duration and the negative urgency dimension of the UPPS-P Impulsive Behavior Scale. Global gray matter volumes were also significant mediators for behavioral problems as measured with the Child Behavior Checklist. CONCLUSIONS Our findings suggest that breastfeeding is a relevant factor in the proper development of the brain, particularly for the pars orbitalis and lateral orbitofrontal cortex regions. This, in turn, may impact impulsive personality and mental health in early puberty.
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Affiliation(s)
- Christian Núñez
- Mental Health Research Group, Institut d'Investigació Biomèdica Sant Pau (IIB Sant Pau), Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Alfredo García-Alix
- Neonatal Neurology, NeNe Foundation, Madrid, Spain
- Iberoamerican Society of Neonatology (SIBEN), NJ, United States
| | - Gemma Arca
- Neonatal Neurology, NeNe Foundation, Madrid, Spain
- Department of Neonatology, Hospital Clínic, IDIBAPS, Barcelona, Spain
| | - Thais Agut
- Neonatal Neurology, NeNe Foundation, Madrid, Spain
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
- Department of Neonatology, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Nuria Carreras
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
- Department of Neonatology, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Maria J Portella
- Mental Health Research Group, Institut d'Investigació Biomèdica Sant Pau (IIB Sant Pau), Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
- Department of Psychiatry and Forensic Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
- Networking Research Center on Mental Health (CIBERSAM), Madrid, Spain
| | - Christian Stephan-Otto
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
- Networking Research Center on Mental Health (CIBERSAM), Madrid, Spain
- Pediatric Computational Imaging Group (PeCIC), Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
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Al-Soufi L, Costas J. Genetic susceptibility for schizophrenia after adjustment by genetic susceptibility for smoking: implications in identification of risk genes and genetic correlation with related traits. Psychol Med 2023; 53:1-11. [PMID: 36876478 DOI: 10.1017/s0033291723000326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
BACKGROUND Prevalence of smoking in schizophrenia (SCZ) is larger than in general population. Genetic studies provided some evidence of a causal effect of smoking on SCZ. We aim to characterize the genetic susceptibility to SCZ affected by genetic susceptibility to smoking. METHODS Multi-trait-based conditional and joint analysis was applied to the largest European SCZ genome-wide association studies (GWAS) to remove genetic effects on SCZ driven by smoking, estimated by generalized summary data-based Mendelian randomization. Enrichment analysis was performed to compare original v. conditional GWAS. Change in genetic correlation between SCZ and relevant traits after conditioning was assessed. Colocalization analysis was performed to identify specific loci confirming general findings. RESULTS Conditional analysis identified 19 new risk loci for SCZ and 42 lost loci whose association with SCZ may be partially driven by smoking. These results were strengthened by colocalization analysis. Enrichment analysis indicated a higher association of differentially expressed genes at prenatal brain stages after conditioning. Genetic correlation of SCZ with substance use and dependence, attention deficit-hyperactivity disorder, and several externalizing traits significantly changed after conditioning. Colocalization of association signal between SCZ and these traits was identified for some of the lost loci, such as CHRNA2, CUL3, and PCDH7. CONCLUSIONS Our approach led to identification of potential new SCZ loci, loci partially associated to SCZ through smoking, and a shared genetic susceptibility between SCZ and smoking behavior related to externalizing phenotypes. Application of this approach to other psychiatric disorders and substances may lead to a better understanding of the role of substances on mental health.
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Affiliation(s)
- Laila Al-Soufi
- Psychiatric Genetics group, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Santiago de Compostela, Galicia, Spain
- Red de Investigación en Atención Primaria de Adicciones (RIAPAd), Spain
- Department of Zoology, Genetics and Physical Anthropology, Universidade de Santiago de Compostela (USC), Santiago de Compostela, Galicia, Spain
| | - Javier Costas
- Psychiatric Genetics group, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Santiago de Compostela, Galicia, Spain
- Red de Investigación en Atención Primaria de Adicciones (RIAPAd), Spain
- Complexo Hospitalario Universitario de Santiago de Compostela (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Galicia, Spain
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Juríčková V, Linhartová P, Adámek P, Nichtová A, Figueroa J, Páv M, Preiss M, Vevera J. Behavioral inhibition in neutral and emotional contexts in acutely violent patients with schizophrenia spectrum disorders. CURRENT PSYCHOLOGY 2022. [DOI: 10.1007/s12144-022-03415-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Lau JH, Jeyagurunathan A, Shafie S, Chang S, Samari E, Cetty L, Verma S, Tang C, Subramaniam M. The factor structure of the Barratt Impulsiveness Scale (BIS-11) and correlates of impulsivity among outpatients with schizophrenia and other psychotic disorders in Singapore. BMC Psychiatry 2022; 22:226. [PMID: 35361174 PMCID: PMC8968701 DOI: 10.1186/s12888-022-03870-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 03/21/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Impulsivity has been linked to risky behaviours amongst patients with schizophrenia or other psychotic disorders. However, there is a dearth of studies examining impulsivity amongst this population in Singapore. Moreover, to date, scales to measure impulsivity have not been validated in this population. The present study seeks to examine the underlying factor structure of the Barratt Impulsiveness Scale (BIS-11) and explore sociodemographic and clinical correlates of impulsivity within this group. METHODS Confirmatory factor analyses (CFA) were conducted to test factor structures of the BIS-11 proposed in extant literature. However, due to poor fit statistics, the sample (n = 397) was split into two groups, with Exploratory Factor Analyses (EFA) conducted in the first subgroup (n = 200). The final model of the EFA was then tested within the second subgroup (n = 197) with CFA. Multivariable linear regressions were conducted to examine sociodemographic and clinical correlates of each underlying factor. RESULTS CFA indicated a three-factor structure amongst 16-items of the BIS-11 with acceptable fit: i) Non-planning impulsivity (5-items; α = 0.94), ii) Motor impulsiveness (6-items α = 0.84), and iii) Lack of self-control (5-items, α = 0.85). Lower education was associated with higher non-planning impulsivity. While age, ethnicity, marital status, and general psychiatric symptom severity were significant correlates of motor impulsiveness, problematic alcohol use and general psychiatric symptom severity were related to a greater lack of self-control. CONCLUSION Factor structures of the BIS-11 suggested by extant literature were not applicable, and we propose an alternative factor structure for BIS-11. Significant correlates of impulsivity are highlighted, and avenues for future research are suggested.
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Affiliation(s)
- Jue Hua Lau
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
| | - Anitha Jeyagurunathan
- Research Division, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747, Singapore.
| | - Saleha Shafie
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
| | - Sherilyn Chang
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
| | - Ellaisha Samari
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
| | - Laxman Cetty
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
| | - Swapna Verma
- grid.414752.10000 0004 0469 9592Medical Board, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
| | - Charmaine Tang
- grid.414752.10000 0004 0469 9592Department of Early Psychosis Intervention, Institute of Mental Health Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
| | - Mythily Subramaniam
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore, 539747 Singapore
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Yi Y, Huang Y, Chen Q, Yang H, Li H, Feng Y, Feng S, Zhou S, Li Z, Wu F. Violence, neurocognitive function and clinical correlates in patients with schizophrenia. Front Psychiatry 2022; 13:1087372. [PMID: 36741559 PMCID: PMC9893505 DOI: 10.3389/fpsyt.2022.1087372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/28/2022] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Schizophrenia patients with violent behavior are a severe public health concern, but the correlates of this violent behavior are unknown. Additionally, the relationship between neurocognitive function and violent behavior in Chinese patients with schizophrenia has not yet been investigated. METHODS A total of 337 schizophrenia inpatients were recruited. The Positive and Negative Syndrome Scale (PANSS) was used to assess psychopathological symptoms. Neurocognitive functioning was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). RESULTS The percentage of violent behavior was 10.4% in patients with schizophrenia. Patients with violent behavior had higher PANSS-positive, excited, and total subscale scores than patients who did not show violent behavior. Patients with violent behavior also had lower RBANS language, semantic fluency, and total subscale scores. Gender (OR = 0.066∼0.819, p = 0.023), illness duration (OR = 0.876∼0.971, p = 0.002), smoking (OR = 1.127∼2.950, p = 0.014), the PANSS positive subscale (OR = 1.050∼1.197, p = 0.001), and the RBANS language subscale (OR = 0.927∼0.987, p = 0.005) significantly contributed to the development of violent behavior in schizophrenia patients. CONCLUSION Our findings revealed that cognitive and clinical assessments should be considered in comprehensive assessments of future risks of violence in schizophrenia patients.
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Affiliation(s)
- Yun Yi
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Psychiatry, The Brain Hospital of Guangxi Zhuang Autonomous Region, Guangxi, China
| | - Yuanyuan Huang
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Qiang Chen
- Department of Psychiatry, The Brain Hospital of Guangxi Zhuang Autonomous Region, Guangxi, China
| | - Hanlun Yang
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen, China
| | - Hehua Li
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yangdong Feng
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Shixuan Feng
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Sumiao Zhou
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zezhi Li
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China.,Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, China
| | - Fengchun Wu
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China.,Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, China.,Department of Biomedical Engineering, Guangzhou Medical University, Guangzhou, China
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11
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Altered Effective Connectivity within an Oculomotor Control Network in Unaffected Relatives of Individuals with Schizophrenia. Brain Sci 2021; 11:brainsci11091228. [PMID: 34573248 PMCID: PMC8467791 DOI: 10.3390/brainsci11091228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 11/17/2022] Open
Abstract
The ability to rapidly stop or change a planned action is a critical cognitive process that is impaired in schizophrenia. The current study aimed to examine whether this impairment reflects familial vulnerability to schizophrenia across two experiments comparing unaffected first-degree relatives to healthy controls. First, we examined performance on a saccadic stop-signal task that required rapid inhibition of an eye movement. Then, in a different sample, we investigated behavioral and neural responses (using fMRI) during a stop-signal task variant that required rapid modification of a prepared eye movement. Here, we examined differences between relatives and healthy controls in terms of activation and effective connectivity within an oculomotor control network during task performance. Like individuals with schizophrenia, the unaffected relatives showed behavioral evidence for more inefficient inhibitory processes. Unlike previous findings in individuals with schizophrenia, however, the relatives showed evidence for a compensatory waiting strategy. Behavioral differences were accompanied by more activation among the relatives in task-relevant regions across conditions and group differences in effective connectivity across the task that were modulated differently by the instruction to exert control over a planned saccade. Effective connectivity parameters were related to behavioral measures of inhibition efficiency. The results suggest that individuals at familial risk for schizophrenia were engaging an oculomotor control network differently than controls and in a way that compromises inhibition efficiency.
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12
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Buck JM, Yu L, Knopik VS, Stitzel JA. DNA methylome perturbations: an epigenetic basis for the emergingly heritable neurodevelopmental abnormalities associated with maternal smoking and maternal nicotine exposure†. Biol Reprod 2021; 105:644-666. [PMID: 34270696 PMCID: PMC8444709 DOI: 10.1093/biolre/ioab138] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/29/2021] [Accepted: 07/14/2021] [Indexed: 11/13/2022] Open
Abstract
Maternal smoking during pregnancy is associated with an ensemble of neurodevelopmental consequences in children and therefore constitutes a pressing public health concern. Adding to this burden, contemporary epidemiological and especially animal model research suggests that grandmaternal smoking is similarly associated with neurodevelopmental abnormalities in grandchildren, indicative of intergenerational transmission of the neurodevelopmental impacts of maternal smoking. Probing the mechanistic bases of neurodevelopmental anomalies in the children of maternal smokers and the intergenerational transmission thereof, emerging research intimates that epigenetic changes, namely DNA methylome perturbations, are key factors. Altogether, these findings warrant future research to fully elucidate the etiology of neurodevelopmental impairments in the children and grandchildren of maternal smokers and underscore the clear potential thereof to benefit public health by informing the development and implementation of preventative measures, prophylactics, and treatments. To this end, the present review aims to encapsulate the burgeoning evidence linking maternal smoking to intergenerational epigenetic inheritance of neurodevelopmental abnormalities, to identify the strengths and weaknesses thereof, and to highlight areas of emphasis for future human and animal model research therein.
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Affiliation(s)
- Jordan M Buck
- Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, CO, USA
- Department of Integrative Physiology, University of Colorado, Boulder, Boulder, CO, USA
| | - Li Yu
- Department of Human Development and Family Studies, Purdue University, West Lafayette, IN, USA
| | - Valerie S Knopik
- Department of Human Development and Family Studies, Purdue University, West Lafayette, IN, USA
| | - Jerry A Stitzel
- Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, CO, USA
- Department of Integrative Physiology, University of Colorado, Boulder, Boulder, CO, USA
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13
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Lehet M, Tso IF, Neggers SFW, Thompson IA, Yao B, Kahn RS, Thakkar KN. Altered effective connectivity within an oculomotor control network in individuals with schizophrenia. Neuroimage Clin 2021; 31:102764. [PMID: 34284336 PMCID: PMC8313596 DOI: 10.1016/j.nicl.2021.102764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/09/2021] [Accepted: 07/10/2021] [Indexed: 11/22/2022]
Abstract
Rapid inhibition or modification of actions is a crucial cognitive ability, which is impaired in persons with schizophrenia (SZP). Primate neurophysiology studies have identified a network of brain regions that subserves control over gaze. Here, we examine effective connectivity within this oculomotor control network in SZP and healthy controls (HC). During fMRI, participants performed a stop-signal task variant in which they were instructed to saccade to a visual target (no-step trials) unless a second target appeared (redirect trials); on redirect trials, participants were instructed to inhibit the planned saccade and redirect to the new target. We compared functional responses on redirect trials to no-step trials and used dynamic causal modelling (DCM) to examine group differences in network effective connectivity. Behaviorally, SZP were less efficient at inhibiting, which was related to their employment status. Compared to HC, they showed a smaller difference in activity between redirect trials and no-step trials in frontal eye fields (FEF), supplementary eye fields (SEF), inferior frontal cortex (IFC), thalamus, and caudate. DCM analyses revealed widespread group differences in effective connectivity across the task, including different patterns of self-inhibition in many nodes in SZP. Group differences in how effective connectivity was modulated on redirect trials revealed differences between the FEF and SEF, between the SEF and IFC, between the superior colliculus and the thalamus, and self-inhibition within the FEF and caudate. These results provide insight into the neural mechanisms of inefficient inhibitory control in individuals with schizophrenia.
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Affiliation(s)
- Matthew Lehet
- Department of Psychology, Michigan State University, East Lansing, MI, USA
| | - Ivy F Tso
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | | | - Ilse A Thompson
- Department of Psychiatry, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Beier Yao
- Department of Psychology, Michigan State University, East Lansing, MI, USA
| | - René S Kahn
- Department of Psychiatry, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Katharine N Thakkar
- Department of Psychology, Michigan State University, East Lansing, MI, USA; Department of Psychiatry, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Psychiatry and Biobehavioral Medicine, Michigan State University, Grand Rapids, MI, USA.
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14
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Jia LX, Qin XJ, Cui JF, Zheng Q, Yang TX, Wang Y, Chan RCK. An ERP study on proactive and reactive response inhibition in individuals with schizotypy. Sci Rep 2021; 11:8394. [PMID: 33863942 PMCID: PMC8052443 DOI: 10.1038/s41598-021-87735-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 04/01/2021] [Indexed: 11/23/2022] Open
Abstract
Schizotypy, a subclinical group at risk for schizophrenia, has been found to show impairments in response inhibition. However, it remains unclear whether this impairment is accompanied by outright stopping (reactive inhibition) or preparation for stopping (proactive inhibition). We recruited 20 schizotypy and 24 non-schizotypy individuals to perform a modified stop-signal task with electroencephalographic (EEG) data recorded. This task consists of three conditions based on the probability of stop signal: 0% (no stop trials, only go trials), 17% (17% stop trials), and 33% (33% stop trials), the conditions were indicated by the colour of go stimuli. For proactive inhibition (go trials), individuals with schizotypy exhibited significantly lesser increase in go response time (RT) as the stop signal probability increasing compared to non-schizotypy individuals. Individuals with schizotypy also exhibited significantly increased N1 amplitude on all levels of stop signal probability and increased P3 amplitude in the 17% stop condition compared with non-schizotypy individuals. For reactive inhibition (stop trials), individuals with schizotypy exhibited significantly longer stop signal reaction time (SSRT) in both 17% and 33% stop conditions and smaller N2 amplitude on stop trials in the 17% stop condition than non-schizotypy individuals. These findings suggest that individuals with schizotypy were impaired in both proactive and reactive response inhibition at behavioural and neural levels.
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Affiliation(s)
- Lu-Xia Jia
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Xiao-Jing Qin
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Ji-Fang Cui
- Research Center for Information and Statistics, National Institute of Education Sciences, Beijing, China
| | - Qi Zheng
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Tian-Xiao Yang
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Ya Wang
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China. .,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
| | - Raymond C K Chan
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
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15
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Martin S, Graziani P, Del-Monte J. Comparing impulsivity in borderline personality, schizophrenia and obsessional-compulsive disorders: Who is ahead? J Clin Psychol 2021; 77:1732-1744. [PMID: 33822353 DOI: 10.1002/jclp.23129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/18/2021] [Accepted: 03/03/2021] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Impulsivity impacts life domains and in a psychiatric context is often associated with disorders severity and stigmatization. Borderline personality disorder's (BPD), Schizophrenic disorder's (SZD), and obsessional compulsive disorder's (OCD) impulsivity issues relate to worse prognosis. This study aims to compare these disorders assessing their proneness to impulsivity and urgency. METHODS We recruited 90 patients among them OCD (n = 25), SZD (n = 23), and BPD (n = 50), and 24 healthy control participants (HC). We assessed the diagnosis according and measured the impulsivity level. RESULTS Our results showed that BPD was significantly more impulsive than HC, SZD, and OCD. HC, SZD, and OCD being equivalent on their global Urgency-Premeditation-Perseverance-Sensation seeking scores. For urgency, BPD was also superior to others, OCD was superior to HC, but SZD and HC were equivalent. The urgency was correlated to SZD's scale for SZD, no link appeared between borderline personality questionnaire and Yale-Brown Obsessive-Compulsive Scale's score. CONCLUSION These results question the existent literature relating impulsivity and SZD.
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Affiliation(s)
- Sylvia Martin
- Psychosocial Laboratory, Aix-Marseille and Nîmes Universities, Nîmes, France.,Nîmes University, Nîmes, France
| | - Pierluigi Graziani
- Psychosocial Laboratory, Aix-Marseille and Nîmes Universities, Nîmes, France
| | - Jonathan Del-Monte
- Psychosocial Laboratory, Aix-Marseille and Nîmes Universities, Nîmes, France
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16
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Boka E, Pozzo JD, Goetz D, Remsen B, Walsh-Messinger J, Getz M, Antonius D, Malaspina D. Ineffective risk-reward learning in schizophrenia. Psychiatry Res 2020; 293:113370. [PMID: 32798934 DOI: 10.1016/j.psychres.2020.113370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 08/02/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022]
Abstract
The underpinnings of poor decision-making in schizophrenia could reflect excessively risky or inhibited behaviors. This study employed the Balloon Analogue Risk Task (BART) to compare decision-making in schizophrenia cases to that of healthy controls. Individuals with schizophrenia performed significantly differently across three trials, failing to improve their performance as shown by the control group. In the control group, cognitive ability, measured with the Wechsler Adult Intelligence Scale (WAIS-III) showed that Perceptual Organization scores predicted Average Inflations per Trial, Total Balloon Pops, and Total Earnings. Although the schizophrenia cases failed to learn, group performance on the BART was not associated with cognitive ability, but regression analyses showed 41.4% of average inflations per trial were explained by Excitement, Delusions, Emotional Withdrawal, and Poor Rapport; total balloon pops were only explained by emotional withdrawal and Total Earnings were reduced by Delusions, Excitement and Poor Rapport. Only healthy participants demonstrated a relation between cognitive ability performance improvement across trials. Schizophrenia cases showed less risk-taking, and earned significantly less money overall. Identifying the determinants of poor decision-making could inform interventions and possible treatments to improve their function and perhaps be of relevance to public safety if decisions are overly risky.
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Affiliation(s)
- Emeka Boka
- Department of Psychiatry, Neuroscience, Genetics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jill Del Pozzo
- Department of Psychology, Montclair State University, Montclair, NJ, USA
| | - Deborah Goetz
- Department of Psychiatry, Neuroscience, Genetics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Brooke Remsen
- Department of Psychiatry, Neuroscience, Genetics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Julie Walsh-Messinger
- Department of Psychology, University of Dayton, Dayton, OH, USA; Department of Psychiatry, Wright State University Boonshoft School of Medicine, Dayton, OH, USA
| | - Mara Getz
- Department of Psychiatry, Neuroscience, Genetics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Daniel Antonius
- Department of Psychiatry, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, USA.
| | - Dolores Malaspina
- Department of Psychiatry, Neuroscience, Genetics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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17
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Elevated Serum Ceruloplasmin Levels Are Associated with Higher Impulsivity in People with Parkinson's Disease. PARKINSONS DISEASE 2020; 2020:8296203. [PMID: 33062249 PMCID: PMC7545407 DOI: 10.1155/2020/8296203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/21/2020] [Accepted: 09/19/2020] [Indexed: 12/21/2022]
Abstract
Background Heightened impulsivity has been reported in a subset of people with Parkinson's disease (PwP) and is considered a risk factor for the development of impulse control disorders (ICDs). However, at present, there are no recognised biochemical markers of heightened impulsivity. Objectives To determine if ceruloplasmin, a serum marker involved in the regulation of iron and copper homeostasis, is associated with trait impulsivity in PwP. Methods The study measured serum ceruloplasmin and impulsivity using the Barratt Impulsiveness Scale (BIS-11) in an Australian cohort of 214 PwP. Multivariate general linear models (GLMs) were used to identify whether higher serum ceruloplasmin levels (>75th percentile) were significantly predictive of BIS-11 scores. Results Serum ceruloplasmin was higher in females with PD (p < 0.001) and associated with MDS-UPDRS III, Hoehn and Yahr, and ACE-R scores (p < 0.05). When correcting for covariates, higher serum ceruloplasmin concentrations were associated with the 2nd order nonplanning impulsivity and with the 1st order self-control and cognitive complexity impulsivity domains. Conclusions Higher serum ceruloplasmin levels are independently associated with heightened nonplanning impulsivity in PwP. Thus, serum ceruloplasmin levels may have clinical utility as a marker for heightened impulsivity in PD.
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18
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van Erp TG, Baker RA, Cox K, Okame T, Kojima Y, Eramo A, Potkin SG. Effect of brexpiprazole on control of impulsivity in schizophrenia: A randomized functional magnetic resonance imaging study. Psychiatry Res Neuroimaging 2020; 301:111085. [PMID: 32450497 DOI: 10.1016/j.pscychresns.2020.111085] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/08/2020] [Accepted: 04/11/2020] [Indexed: 12/21/2022]
Abstract
Impulsivity in schizophrenia is a risk factor for suicide, drug abuse, and other risk-taking behaviors. This exploratory, multicenter, randomized, double-blind, functional magnetic resonance imaging (fMRI) study assessed the effects of brexpiprazole on brain regions that control impulsive behavior. Thirty-eight outpatients with stable schizophrenia and impulsivity symptoms were randomized to 6 weeks of brexpiprazole 2 or 4 mg/day. The prespecified outcome measure was blood oxygen-level dependent (BOLD) activation in the right ventrolateral prefrontal cortex (VLPFC) during performance of tasks associated with inhibition/control of impulsivity: the go/no-go task and stop-signal task. Secondary objectives evaluated the efficacy, safety and tolerability of brexpiprazole. Over 6 weeks, patients receiving brexpiprazole had no statistically significant change in right VLPFC BOLD activation during the go/no-go task, but showed a significant decrease in right VLPFC BOLD activation during the stop-signal task. Brexpiprazole was also associated with significantly improved stop-signal reaction time (SSRT). No worsening of psychiatric symptoms, functioning, or impulsivity occurred in these patients. No unexpected safety or tolerability concerns were identified. In conclusion, brexpiprazole treatment among patients with schizophrenia and impulsivity was associated with decreased right VLPFC activation and decreased SSRT, supportive of a benefit of brexpiprazole on inhibition-related brain activation and behavior. ClinicalTrials.gov identifier: NCT02194933.
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Affiliation(s)
- Theo Gm van Erp
- Clinical and Translational Neuroscience Laboratory, University of California-Irvine, Irvine, CA, United States; Center for the Neurobiology of Learning and Memory, University of California-Irvine, Irvine, CA, United States.
| | - Ross A Baker
- Otsuka Pharmaceutical Development & Commercialization Inc., Princeton, NJ, United States
| | - Kevin Cox
- Otsuka Pharmaceutical Development & Commercialization Inc., Princeton, NJ, United States
| | - Takao Okame
- Otsuka Pharmaceutical Co. Ltd., Kanda Tsukasa-machi, Chiyoda-ku, Tokyo101-8535, Japan
| | - Yoshitsugu Kojima
- Otsuka Pharmaceutical Co. Ltd., Kanda Tsukasa-machi, Chiyoda-ku, Tokyo101-8535, Japan
| | - Anna Eramo
- Lundbeck LLC, Deerfield, IL, United States
| | - Steven G Potkin
- University of California-Irvine, Irvine, CA, United States; Tibor Rubin Veterans Affairs Medical Center, Long Beach, CA, United States.
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19
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Pickering JS, Leroi I, McBride J, Poliakoff E. Continuous force measurements reveal no inhibitory control deficits in Parkinson's disease. Exp Brain Res 2020; 238:1119-1132. [PMID: 32222777 PMCID: PMC7237404 DOI: 10.1007/s00221-020-05768-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 03/03/2020] [Indexed: 11/26/2022]
Abstract
Suppression of unwanted motor responses can be disrupted by Parkinson’s disease. People with Parkinson’s (PwP) can show maladaptive reward-driven behaviours in the form of impulse control behaviours, which are associated with the use of the dopaminergic treatments used to alleviate the motor symptoms of the disease. However, the effects of Parkinson’s itself on impulsive behaviour and control are unclear—empirical studies have yielded mixed findings, and some imaging studies have shown a functional deficit in the absence of a measurable change in behaviour. Here, we investigated the effects of Parkinson’s on response activation and control by studying the dynamics of response in standard inhibitory control tasks—the Stop Signal and Simon tasks—using a continuous measure of response force. Our results are largely in favour of the conclusion that response inhibition appears to be intact in PwP, even when using a more sensitive measure of behavioural control relative to traditional button-press measures. Our findings provide some clarity as to the effects of Parkinson’s on response inhibition and show continuous response force measurement can provide a sensitive means of detecting erroneous response activity in PwP, which could also be generalised to studying related processes in other populations.
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Affiliation(s)
- Jade S Pickering
- Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, M13 9PL, UK
| | - Iracema Leroi
- Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, M13 9PL, UK
- Global Brain Health Institute, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Jennifer McBride
- Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, M13 9PL, UK
| | - Ellen Poliakoff
- Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, M13 9PL, UK.
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20
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Desbonnet L, O'Tuathaigh CM, O'Leary C, Cox R, Tighe O, Petit EI, Wilson S, Waddington JL. Acute stress in adolescence vs early adulthood following selective deletion of dysbindin-1A: Effects on anxiety, cognition and other schizophrenia-related phenotypes. J Psychopharmacol 2019; 33:1610-1619. [PMID: 31556815 DOI: 10.1177/0269881119875465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND As exposure to stress has been linked to the onset and maintenance of psychotic illness, its pathogenesis may involve environmental stressors interacting with genetic vulnerability. AIM To establish whether acute stress interacts with a targeted mutation of the gene encoding the neurodevelopmental factor dystrobrevin-binding protein 1 (DTNBP1), resulting in a specific loss of the isoform dysbindin-1A, to influence schizophrenia-relevant phenotypes in mice during adolescence and adulthood. METHODS Male and female mice with a heterozygous or homozygous deletion of DTNBP1 were assessed in the open field test following acute restraint stress in adolescence (Day 35) and young adulthood (Day 60-70). Effects of acute restraint stress on memory retention in the novel object recognition test was also assessed in adulthood. Baseline corticosterone was measured in serum samples and, brain-derived neurotrophic factor (BDNF), glucocorticoid and mineralocorticoid receptor gene expression levels were measured in the hippocampus of adult mice. RESULTS In the open field, deletion of dysbindin-1A induced hyperactivity and attenuated the action of stress to reduce hyperactivity in adolescence but not in adulthood; in females deletion of dysbindin-1A attenuated the effect of acute stress to increase anxiety-related behaviour in adolescence but not in adulthood. In the novel object recognition test, deletion of dysbindin-1A impaired memory and also revealed an increase in anxiety-related behaviour and a decrease in hippocampal BDNF gene expression in males. CONCLUSIONS These data suggest that deletion of dysbindin-1A influences behaviours related to schizophrenia and anxiety more robustly in adolescence than in adulthood and that dysbindin-1A influences stress-related responses in a sex-dependent manner.
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Affiliation(s)
- Lieve Desbonnet
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.,School of Psychology, National University of Ireland, Galway, Ireland
| | - Colm Mp O'Tuathaigh
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.,School of Medicine, Brookfield Health Sciences Complex, University College Cork, Cork, Ireland
| | - Clare O'Leary
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Rachel Cox
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Orna Tighe
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Emilie I Petit
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Steve Wilson
- In Vivo Science and Delivery, GlaxoSmithKline, Stevenage, UK
| | - John L Waddington
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psychiatric Disorders and Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, China
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21
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Lu J, Li S, Li H, Mou T, Zhou L, Huang B, Huang M, Xu Y. Changes In Plasma NPY, IL-1β And Hypocretin In People Who Died By Suicide. Neuropsychiatr Dis Treat 2019; 15:2893-2900. [PMID: 31632037 PMCID: PMC6791488 DOI: 10.2147/ndt.s219962] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/12/2019] [Indexed: 12/31/2022] Open
Abstract
PURPOSE There is growing evidence showing that inflammatory cytokines and neuropeptides may be involved in the pathophysiology of suicidal behavior. However, studies have yielded contradictory data, and no biological markers that help predict suicide have been identified. This study aimed to identify biological patterns, such as NPY, IL-1β and hypocretin plasma levels, in people who died by suicide. PATIENTS AND METHODS Twenty-two people who died by suicide compared with 22 controls matched for age and sex were studied. In suicide and control subjects, we estimated the levels of NPY, IL-1β and hypocretin in plasma using enzyme-linked immunosorbent assay. The data are presented as the median (25th-75th percentile). RESULTS We found (1) a significant elevation in plasma NPY levels in suicide subjects versus control subjects (suicide: 11.38 (9.380-16.55); controls: 8.95 (7.590-10.93); P=0.013), and plasma NPY concentrations were approximately 62% higher in suicide subjects than those in control subjects; (2) a significant decrease in plasma IL-1β concentrations between suicide and control subjects (suicide: 121.1 (82.97-143.0); controls: 425.9 (233.1-835.3); P<0.001) as well as a decrease in IL-1β concentrations by almost 80%; and (3) no significant difference in plasma hypocretin levels between suicide and control subjects (suicide: 16.62 (13.62-25.77); controls: 21.63 (14.97-29.72); P=0.356). CONCLUSION Our results suggest that plasma NPY and IL-1β were related with suicide behavior rather than to suicide causes or suicide method. Specific combinations of plasma biomarkers may discriminate between types of suicidal behaviors and indicate increased risk for future suicide attempts.
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Affiliation(s)
- Jing Lu
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang University Brain Research Institute, Hangzhou, Zhejiang Province, People's Republic of China
| | - Shangda Li
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang University Brain Research Institute, Hangzhou, Zhejiang Province, People's Republic of China
| | - Haimei Li
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang University Brain Research Institute, Hangzhou, Zhejiang Province, People's Republic of China
| | - Tingting Mou
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang University Brain Research Institute, Hangzhou, Zhejiang Province, People's Republic of China
| | - Lihong Zhou
- Institute of Criminal Science and Technology, Hangzhou Public Security Bureau, Hangzhou, Zhejiang Province, People's Republic of China
| | - Bochao Huang
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang University Brain Research Institute, Hangzhou, Zhejiang Province, People's Republic of China
| | - Manli Huang
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang University Brain Research Institute, Hangzhou, Zhejiang Province, People's Republic of China
| | - Yi Xu
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang University Brain Research Institute, Hangzhou, Zhejiang Province, People's Republic of China
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Nguyen R, Brooks M, Bruno R, Peacock A. Behavioral measures of state impulsivity and their psychometric properties: A systematic review. PERSONALITY AND INDIVIDUAL DIFFERENCES 2018. [DOI: 10.1016/j.paid.2018.06.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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A cross-sectional survey of psychotic symptoms in the community: The GRANAD∑P psychosis study. EUROPEAN JOURNAL OF PSYCHIATRY 2018. [DOI: 10.1016/j.ejpsy.2017.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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24
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Reduced pupil dilation during action preparation in schizophrenia. Int J Psychophysiol 2018; 128:111-118. [PMID: 29574231 DOI: 10.1016/j.ijpsycho.2018.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/30/2018] [Accepted: 03/19/2018] [Indexed: 11/22/2022]
Abstract
Impairments in cognitive control-the ability to exert control over thoughts and actions and respond flexibly to the environment-are well-documented in schizophrenia. However, the degree to which experimental task performance reflects true cognitive control impairments or more general alterations in effort, arousal and/or task preparedness is unclear. Pupillary responses can provide insight into these latter factors, as the pupil dilates with degree of cognitive effort and response preparation. In the current study, 16 medicated outpatients with schizophrenia (SZP) and 18 healthy controls performed a task that measures the ability to reactively inhibit and modify a planned action-the double-step task. In this task, participants were required to make a saccade to a visual target. Infrequently, the target jumped to a new location and participants were instructed to rapidly inhibit and change their eye movement plan. Applying a race model of performance, we have previously shown that SZP require more time to inhibit a planned action. In the current analysis, we measured pupil dilation associated with task preparation and found that SZP had a shallower increase in pupil size prior to the onset of the trial. Additionally, reduced magnitude of the pupil response was associated with negative symptom severity in patients. Based on primate neurophysiology and cognitive neuroscience work, we suggest that this blunted pupillary response may reflect abnormalities in a general orienting response or reduced motivational significance of a cue signifying the onset of a preparatory period and that these abnormalities might share an autonomic basis with negative symptoms.
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Ho BC, Barry AB, Koeppel JA. Impulsivity in unaffected adolescent biological relatives of schizophrenia patients. J Psychiatr Res 2018; 97:47-53. [PMID: 29175297 PMCID: PMC5742548 DOI: 10.1016/j.jpsychires.2017.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/03/2017] [Accepted: 11/17/2017] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Although schizophrenia is not a prototypic impulse-control disorder, patients report more impulsive behaviors, have higher rates of substance use, and show dysfunction in brain circuits that underlie impulsivity. We investigate impulsivity in unaffected biological relatives of schizophrenia patients to further understand the relationships between schizophrenia risk and impulse control during adolescence. METHOD Group differences in impulsivity (UPPS-P Impulsive Behavior Scale and delay discounting) were tested in 210 adolescents contrasting 39 first- and 53 second-degree biological relatives of schizophrenia patients, and 118 subjects with no schizophrenia family history (NSFH). RESULTS Compared to NSFH adolescents and to second-degree relatives, first-degree relatives of schizophrenia patients had increased impulsivity-related behaviors (higher UPPS-P Perseverance, Positive Urgency and Premeditation subscale scores) and greater preference for immediate rewards (smaller AUC and larger discounting constant). Second-degree relatives did not differ significantly from NSFH adolescents on self-report impulsive behaviors or on measures of impulsive decision-making. These group differences remained even after careful consideration of potential confounding factors. CONCLUSION Impulsivity is associated with schizophrenia risk, and its severity increases with greater familial relatedness to the schizophrenia proband. Additional studies are needed to understand the role impulsivity may play in mediating schizophrenia susceptibility during adolescence.
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Affiliation(s)
- Beng-Choon Ho
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
| | - Amy B Barry
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Julie A Koeppel
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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Šagud M, Vuksan-Ćusa B, Jakšić N, Mihaljević-Peleš A, Živković M, Vlatković S, Prgić T, Marčinko D, Wang W. Nicotine dependence in Croatian male inpatients with schizophrenia. BMC Psychiatry 2018; 18:18. [PMID: 29357830 PMCID: PMC5778660 DOI: 10.1186/s12888-018-1606-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 01/11/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Patients with schizophrenia have the highest known rates of cigarette smoking, but less is known about their smoking behavior and the differences across geographical regions, including Croatia. The aim of this study was to compare patterns of nicotine dependence between patients with schizophrenia and healthy individuals, and to determine the relationship between clinical presentation and the severity of smoking. METHODS This cross-sectional study included 182 recently hospitalized male inpatients and 280 healthy males, who were daily smokers. All participants have fulfilled the Fagerstrom Test for Nicotine Dependence (FTND). Patients were also evaluated by the Positive and Negative Syndrome Scale (PANSS). RESULTS Patients had higher FTND total score (p = 0.010), smoked their first cigarette earlier in the morning (p = 0.000), consumed higher number of cigarettes (p = 0.000), while healthy subjects had more difficulties to refrain from smoking in places where it is forbidden (p = 0.000) and smoked more even when they were sick (p = 0.000). While severe dependence was more prevalent in the patient group, light dependence was more frequent in control subjects (p = 0.04). Smoking behavior was not associated with either PANSS total score or any of its subscales and items. CONCLUSIONS Smokers with schizophrenia differ from healthy smokers in both smoking behavior and level of dependence. Longitudinal studies are needed to shed more light on the complex relationship between smoking and psychopathology in schizophrenia.
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Affiliation(s)
- Marina Šagud
- School of Medicine, University of Zagreb, Zagreb, Croatia
- Department of Psychiatry, University Hospital Center Zagreb, Kišpatićeva 12, 10 000 Zagreb, Croatia
| | - Bjanka Vuksan-Ćusa
- Department of Psychiatry, University Hospital Center Zagreb, Kišpatićeva 12, 10 000 Zagreb, Croatia
- School of Medicine, University of Osijek, Osijek, Croatia
- School of Medicine, University of Mostar, Mostar, Bosnia and Herzegovina
| | - Nenad Jakšić
- Department of Psychiatry, University Hospital Center Zagreb, Kišpatićeva 12, 10 000 Zagreb, Croatia
| | - Alma Mihaljević-Peleš
- School of Medicine, University of Zagreb, Zagreb, Croatia
- Department of Psychiatry, University Hospital Center Zagreb, Kišpatićeva 12, 10 000 Zagreb, Croatia
| | | | | | - Tea Prgić
- Department of Psychiatry, General Hospital Vinkovci, Vinkovci, Croatia
| | - Darko Marčinko
- School of Medicine, University of Zagreb, Zagreb, Croatia
- Department of Psychiatry, University Hospital Center Zagreb, Kišpatićeva 12, 10 000 Zagreb, Croatia
| | - Wei Wang
- Department of Clinical Psychology and Psychiatry, Zhejiang University College of Medicine, Hangzhou, China
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Hoptman MJ, Parker EM, Nair-Collins S, Dias EC, Ross ME, DiCostanzo JN, Sehatpour P, Javitt DC. Sensory and cross-network contributions to response inhibition in patients with schizophrenia. NEUROIMAGE-CLINICAL 2018; 18:31-39. [PMID: 29868440 PMCID: PMC5984577 DOI: 10.1016/j.nicl.2018.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/12/2017] [Accepted: 01/05/2018] [Indexed: 02/07/2023]
Abstract
Patients with schizophrenia show response inhibition deficits equal to or greater than those seen in impulse-control disorders, and these deficits contribute to poor outcome. However, little is known about the circuit abnormalities underlying this impairment. To address this, we examined stop signal task performance in 21 patients with schizophrenia and 21 healthy controls using event related potential (ERP) and resting state functional connectivity. Patients showed prolonged stop signal reaction time (SSRT) and reduced N1, N2, and P3 amplitudes compared to controls. Across groups, P3 amplitudes were maximal after SSRT (i.e., after the time associated with the decision to stop occurred), suggesting that this component indexed response monitoring. Multiple regression analyses showed that longer SSRTs were independently related to 1) patient status, 2) reduced N1 amplitude on successful stop trials and 3) reduced anticorrelated resting state functional connectivity between visual and frontoparietal cortical networks. This study used a combined multimodal imaging approach to better understand the network abnormalities that underlie response inhibition in schizophrenia. It is the first of its kind to specifically assess the brain's resting state functional architecture in combination with behavioral and ERP methods to investigate response inhibition in schizophrenia. People with schizophrenia show deficits in response inhibition measured using behavioral and ERP methods. Behavioral and ERP measures of response inhibition are correlated. Patient status, reduced N1, and higher resting state functional connectivity separately predicted poorer response inhibition. This study underscores the value of using multimodal imaging to understand response inhibition deficits in schizophrenia.
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Affiliation(s)
- Matthew J Hoptman
- Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University School of Medicine, New York, NY, USA; City University of New York, New York, NY, USA.
| | | | - Sangeeta Nair-Collins
- Nathan Kline Institute, Orangeburg, NY, USA; City University of New York, New York, NY, USA
| | - Elisa C Dias
- Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | | | | | - Pejman Sehatpour
- Nathan Kline Institute, Orangeburg, NY, USA; Department of Experimental Therapeutics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Daniel C Javitt
- Nathan Kline Institute, Orangeburg, NY, USA; Department of Experimental Therapeutics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Neuregulin 3 Mediates Cortical Plate Invasion and Laminar Allocation of GABAergic Interneurons. Cell Rep 2017; 18:1157-1170. [PMID: 28147272 PMCID: PMC5300889 DOI: 10.1016/j.celrep.2016.12.089] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/08/2016] [Accepted: 12/27/2016] [Indexed: 02/07/2023] Open
Abstract
Neural circuits in the cerebral cortex consist of excitatory pyramidal cells and inhibitory interneurons. These two main classes of cortical neurons follow largely different genetic programs, yet they assemble into highly specialized circuits during development following a very precise choreography. Previous studies have shown that signals produced by pyramidal cells influence the migration of cortical interneurons, but the molecular nature of these factors has remained elusive. Here, we identified Neuregulin 3 (Nrg3) as a chemoattractive factor expressed by developing pyramidal cells that guides the allocation of cortical interneurons in the developing cortical plate. Gain- and loss-of-function approaches reveal that Nrg3 modulates the migration of interneurons into the cortical plate in a process that is dependent on the tyrosine kinase receptor ErbB4. Perturbation of Nrg3 signaling in conditional mutants leads to abnormal lamination of cortical interneurons. Nrg3 is therefore a critical mediator in the assembly of cortical inhibitory circuits. Nrg3 acts a short-range chemoattractive molecule for cortical interneurons Nrg3 functions through ErbB4 to attract interneurons into the cortical plate Interneurons prefer Cxcl12 over Nrg3 during tangential migration Disruption of Nrg3 signaling causes abnormal interneuron lamination in the cortex
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Angry but not neutral faces facilitate response inhibition in schizophrenia patients. Eur Arch Psychiatry Clin Neurosci 2017; 267:621-627. [PMID: 27866272 DOI: 10.1007/s00406-016-0748-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 11/06/2016] [Indexed: 10/20/2022]
Abstract
Schizophrenia is a very heterogeneous disorder with extensive impairments in cognitive as well as emotional abilities. One critical domain is response inhibition, and previous studies in schizophrenia patients have mostly observed impairments, i.e., slower inhibition. Moreover, response inhibition to socially salient stimuli has not been investigated in schizophrenia so far. Therefore, to elucidate emotion-cognition interactions by examining potential emotional effects on inhibition processes and further investigate the association of cognition with inhibition we used an emotional stop signal task in 27 schizophrenia patients and 27 gender- and age-matched controls. Task irrelevant emotional faces (angry and neutral) were used as stimuli in a stop signal reaction time task. Regarding accuracy, patients showed significantly worse performance in neutral trials, while their performance in anger trials (stop and go) was similar to controls. Angry faces elicited faster response inhibition in both groups, underlining an emotional facilitation effect. Neurocognitive functions significantly correlated with accuracy in the stop signal task in schizophrenia patients, thus further strengthening the notion of the strong link between cognitive abilities and inhibition processes. Inhibitory control impairments are of high clinical interest due to their association with substance abuse, impulsive behavior and suicide. Based on our data, neutral faces significantly affect response inhibition in schizophrenia while an emotional facilitation effect was apparent for angry faces even in schizophrenia patients. Thus, our data further support the notion that neutral face processing is critically impaired in schizophrenia.
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Carré JM, Geniole SN, Ortiz TL, Bird BM, Videto A, Bonin PL. Exogenous Testosterone Rapidly Increases Aggressive Behavior in Dominant and Impulsive Men. Biol Psychiatry 2017; 82:249-256. [PMID: 27524498 DOI: 10.1016/j.biopsych.2016.06.009] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND Although traditional wisdom suggests that baseline levels of testosterone (T) promote aggressive behavior, decades of research have produced findings that have been largely weak and inconsistent. However, more recent experimental work suggests that exogenous administration of T rapidly potentiates amygdala and hypothalamus responses to angry facial expressions. Notably, these brain regions are rich in androgen receptors and play a key role in modulating aggressive behavior in animal models. METHODS The present experiment extends this work by examining whether acutely increasing T potentiates aggressive behavior in men. In a double-blind, placebo-controlled, between-subject design, healthy adult men (n = 121) were administered either T or placebo, and subsequently engaged in a well-validated decision-making game that measures aggressive behavior in response to social provocation. In light of prior correlational research, we also assessed the extent to which T's effects on aggressive behavior would depend on variability in trait dominance and/or trait self-control. RESULTS Exogenous T on its own did not modulate aggressive behavior. However, T's effects on aggression were strongly influenced by variation in trait dominance and trait self-control. Specifically, T caused an increase in aggressive behavior, but only among men scoring relatively high in trait dominance or low in trait self-control. CONCLUSIONS These findings are the first to demonstrate that T can rapidly (within 60 minutes) potentiate aggressive behavior, but only among men with dominant or impulsive personality styles.
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Affiliation(s)
- Justin M Carré
- Department of Psychology, Nipissing University, North Bay.
| | | | - Triana L Ortiz
- Department of Psychology, Nipissing University, North Bay
| | - Brian M Bird
- Department of Psychology, Laurentian University; Sudbury, Canada
| | - Amber Videto
- Department of Psychology, Nipissing University, North Bay
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Amr M, Elsayed H, Ibrahim IMA. Impulsive behavior and its correlates among patients with schizophrenia in a tertiary care psychiatry setting in Mansoura. Asian J Psychiatr 2016; 22:111-5. [PMID: 27520910 DOI: 10.1016/j.ajp.2016.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/07/2016] [Accepted: 06/19/2016] [Indexed: 02/01/2023]
Abstract
BACKGROUND AND OBJECTIVES Impulsive behavior has been repeatedly identified as a major problem in schizophrenia. Our objective was to examine the possible demographical and clinical correlates for impulsive behavior in patients with schizophrenia. METHODS Fifty-eight patients with schizophrenia and Seventy-seven healthy controls were recruited. Sociodemographic data were collected and they were subjected to the Barratt Impulsiveness Scale (BIS), Positive and Negative Syndrome scale (PANSS), and Trauma Assessment for Adults-Brief Revised Version (TAA). RESULTS Correlations between impulsive behavior and psychosocial variables were examined. A significant association between level of impulsive behavior and severity of psychopathological symptoms was observed (P=0.0001). Young age (P=0.001), male patients (P=0.0001) and those with history of childhood sexual or physical abuse (P=0.0001), were more impulsive. Linear regression (step wise) analysis model showed that male sex (P=0.001), positive symptoms (P=0.006), and childhood physical abuse (P=0.001) were significant associations. CONCLUSION Male gender, positive symptoms as well as history of physical and sexual abuse before 18 years of age are important predictors for high levels of impulsive behavior in schizophrenia patients.
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Affiliation(s)
- Mostafa Amr
- Psychiatry Department, MansouraFaculty of Medicine, Mansoura University, Mansoura, Egypt.
| | - Hanan Elsayed
- Psychiatry Department, MansouraFaculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Ibtihal M A Ibrahim
- Psychiatry Department, MansouraFaculty of Medicine, Mansoura University, Mansoura, Egypt
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Hoptman MJ, Ahmed AO. Neural Foundations of Mood-Induced Impulsivity and Impulsive Aggression in Schizophrenia. Curr Behav Neurosci Rep 2016. [DOI: 10.1007/s40473-016-0081-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Nanda P, Tandon N, Mathew IT, Padmanabhan JL, Clementz BA, Pearlson GD, Sweeney JA, Tamminga CA, Keshavan MS. Impulsivity across the psychosis spectrum: Correlates of cortical volume, suicidal history, and social and global function. Schizophr Res 2016; 170:80-6. [PMID: 26711526 DOI: 10.1016/j.schres.2015.11.030] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 11/24/2015] [Accepted: 11/30/2015] [Indexed: 11/26/2022]
Abstract
Patients with psychotic disorders appear to exhibit greater impulsivity-related behaviors relative to healthy controls. However, the neural underpinning of this impulsivity remains uncertain. Furthermore, it remains unclear how impulsivity might differ or be conserved between psychotic disorder diagnoses in mechanism and manifestation. In this study, self-reported impulsivity, measured by Barratt Impulsiveness Scale (BIS), was compared between 305 controls (HC), 139 patients with schizophrenia (SZ), 100 with schizoaffective disorder (SZA), and 125 with psychotic bipolar disorder (PBP). In each proband group, impulsivity was associated with regional cortical volumes (using FreeSurfer analysis of T1 MRI scans), suicide attempt history, Global Assessment of Functioning (GAF), and Social Functioning Scale (SFS). BIS scores were found to differ significantly between participant groups, with SZA and PBP exhibiting significantly higher impulsivity than SZ, which exhibited significantly higher impulsivity than HC. BIS scores were significantly related to suicide attempt history, and they were inversely associated with GAF, SFS, and bilateral orbitofrontal cortex (OFC) volume in both SZA and PBP, but not SZ. These findings indicate that psychotic disorders, particularly those with prominent affective symptoms, are characterized by elevated self-reported impulsivity measures. Impulsivity's correlations with suicide attempt history, GAF, and SFS suggest that impulsivity may be a mediator of clinical outcome. The observed impulsivity-OFC correlations corroborate the importance of OFC deficits in impulsivity. These correlations' presence in SZA and PBP but not in SZ suggests that impulsivity may have different underlying mechanisms in affective and non-affective psychotic disorders.
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Affiliation(s)
- Pranav Nanda
- College of Physicians & Surgeons, Columbia University Medical Center, New York, NY, USA
| | - Neeraj Tandon
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA; Baylor College of Medicine, Texas Medical Center, Houston, TX, USA
| | - Ian T Mathew
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Jaya L Padmanabhan
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Neurology, McLean Hospital, Belmont, MA, USA
| | - Brett A Clementz
- Department of Psychology, BioImaging Research Center, University of Georgia, Athens, GA, USA; Department of Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, USA
| | - Godfrey D Pearlson
- Olin Neuropsychiatry Research Center, Institute of Living, Hartford, CT, USA; Departments of Psychiatry and Neurobiology, Yale University School of Medicine, New Haven, CT, USA
| | - John A Sweeney
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Carol A Tamminga
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Matcheri S Keshavan
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
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Abstract
Elevations of impulsive behavior have been observed in a number of serious mental illnesses. These phenomena can lead to harmful behaviors, including violence, and thus represent a serious public health concern. Such violence is often a reason for psychiatric hospitalization, and it often leads to prolonged hospital stays, suffering by patients and their victims, and increased stigmatization. Despite the attention paid to violence, little is understood about its neural basis in schizophrenia. On a psychological level, aggression in schizophrenia has been primarily attributed to psychotic symptoms, desires for instrumental gain, or impulsive responses to perceived personal slights. Often, multiple attributions can coexist during a single aggressive incident. In this review, I discuss the neural circuitry associated with impulsivity and aggression in schizophrenia, with an emphasis on implications for treatment. Impulsivity appears to account for a great deal of aggression in schizophrenia, especially in inpatient settings. Urgency, defined as impulsivity in the context of strong emotion, is the primary focus of this article. It is elevated in several psychiatric disorders, and in schizophrenia, it has been related to aggression. Many studies have implicated dysfunctional frontotemporal circuitry in impulsivity and aggression in schizophrenia, and pharmacological treatments may act via that circuitry to reduce urgency and aggressive behaviors; however, more mechanistic studies are critically needed. Recent studies point toward manipulable neurobehavioral targets and suggest that cognitive, pharmacological, neuromodulatory, and neurofeedback treatment approaches can be developed to ameliorate urgency and aggression in schizophrenia. It is hoped that these approaches will improve treatment efficacy.
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Affiliation(s)
- Matthew J. Hoptman
- Research Scientist, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY
- Research Associate Professor, Department of Psychiatry, New York University School of Medicine, New York, NY
- Adjunct Associate Professor, Department of Psychology, City University of New York, New York, NY
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Response inhibition and response monitoring in a saccadic double-step task in schizophrenia. Brain Cogn 2015; 95:90-8. [PMID: 25769133 DOI: 10.1016/j.bandc.2015.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/03/2014] [Accepted: 01/15/2015] [Indexed: 11/20/2022]
Abstract
BACKGROUND Cognitive control impairments are linked to functional outcome in schizophrenia. The goal of the current study was to investigate precise abnormalities in two aspects of cognitive control: reactively changing a prepared response, and monitoring performance and adjusting behavior accordingly. We adapted an oculomotor task from neurophysiological studies of the cellular basis of cognitive control in nonhuman primates. METHODS 16 medicated outpatients with schizophrenia (SZ) and 18 demographically-matched healthy controls performed the modified double-step task. In this task, participants were required to make a saccade to a visual target. Infrequently, the target jumped to a new location and participants were instructed to rapidly inhibit and change their response. A race model provided an estimate of the time needed to cancel a planned movement. Response monitoring was assessed by measuring reaction time (RT) adjustments based on trial history. RESULTS SZ patients had normal visually-guided saccadic RTs but required more time to switch the response to the new target location. Additionally, the estimated latency of inhibition was longer in patients and related to employment. Finally, although both groups slowed down on trials that required inhibiting and changing a response, patients showed exaggerated performance-based adjustments in RTs, which was correlated with positive symptom severity. CONCLUSIONS SZ patients have impairments in rapidly inhibiting eye movements and show idiosyncratic response monitoring. These results are consistent with functional abnormalities in a network involving cortical oculomotor regions, the superior colliculus, and basal ganglia, as described in neurophysiological studies of non-human primates using an identical paradigm, and provide a translational bridge for understanding cognitive symptoms of SZ.
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Fischer BA, McMahon RP, Kelly DL, Wehring HJ, Meyer WA, Feldman S, Carpenter WT, Gorelick DA. Risk-taking in schizophrenia and controls with and without cannabis dependence. Schizophr Res 2015; 161:471-7. [PMID: 25467541 PMCID: PMC4308438 DOI: 10.1016/j.schres.2014.11.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 11/05/2014] [Accepted: 11/09/2014] [Indexed: 11/13/2022]
Abstract
BACKGROUND Risk-based decision making is altered in people with schizophrenia and in people with cannabis use compared to healthy controls; the pattern of risk-assessment in people with co-occurring schizophrenia and cannabis dependence is poorly understood. This study examined measures of risk-taking and decision-making in people with and without schizophrenia and/or cannabis dependence. METHODS Participants with schizophrenia (n=24), cannabis dependence (n=23), schizophrenia and co-occurring cannabis dependence (n=18), and healthy controls (n=24) were recruited from the community via advertisements and completed a one-visit battery of symptom, risk-based decision making, gambling behavior, cognitive, and addiction assessments. This report presents self-assessments of self-mastery, optimism, impulsivity, and sensation seeking and a behavioral assessment of risk (Balloon Analog Risk Task [BART]). RESULTS On self-report measures, participants with schizophrenia and co-occurring cannabis dependence were intermediate between those with only cannabis dependence or only schizophrenia on ratings of self-mastery, sensation-seeking, and impulsivity. There were no group differences on ratings of optimism. Their behavior on the BART was most similar to participants with only cannabis dependence or healthy controls, rather than to participants with only schizophrenia. CONCLUSIONS People with schizophrenia and co-occurring cannabis dependence may represent a unique group in terms of risk-perception and risk-taking. This has implications for interventions designed to influence health behaviors such as motivational interviewing.
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Affiliation(s)
- Bernard A Fischer
- Veterans Affairs Capital Network (VISN 5) Mental Illness Research, Education, and Clinical Center (MIRECC), Department of Veterans Affairs, Baltimore, MD, USA; Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Robert P McMahon
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Deanna L Kelly
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Heidi J Wehring
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Walter A Meyer
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Stephanie Feldman
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - William T Carpenter
- Veterans Affairs Capital Network (VISN 5) Mental Illness Research, Education, and Clinical Center (MIRECC), Department of Veterans Affairs, Baltimore, MD, USA; Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - David A Gorelick
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
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Simon NW, Moghaddam B. Neural processing of reward in adolescent rodents. Dev Cogn Neurosci 2014; 11:145-54. [PMID: 25524828 PMCID: PMC4597598 DOI: 10.1016/j.dcn.2014.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/26/2022] Open
Abstract
The adolescent brain processes rewards differently than in adults. These differences occur even when behavior is similar between age groups. DS was the locus of substantial developmental differences in reward activity. Surprisingly, differences were not as pronounced in VS. These differences may have implications for adolescent psychiatric vulnerability.
Immaturities in adolescent reward processing are thought to contribute to poor decision making and increased susceptibility to develop addictive and psychiatric disorders. Very little is known; however, about how the adolescent brain processes reward. The current mechanistic theories of reward processing are derived from adult models. Here we review recent research focused on understanding of how the adolescent brain responds to rewards and reward-associated events. A critical aspect of this work is that age-related differences are evident in neuronal processing of reward-related events across multiple brain regions even when adolescent rats demonstrate behavior similar to adults. These include differences in reward processing between adolescent and adult rats in orbitofrontal cortex and dorsal striatum. Surprisingly, minimal age related differences are observed in ventral striatum, which has been a focal point of developmental studies. We go on to discuss the implications of these differences for behavioral traits affected in adolescence, such as impulsivity, risk-taking, and behavioral flexibility. Collectively, this work suggests that reward-evoked neural activity differs as a function of age and that regions such as the dorsal striatum that are not traditionally associated with affective processing in adults may be critical for reward processing and psychiatric vulnerability in adolescents.
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Affiliation(s)
- Nicholas W Simon
- University of Pittsburgh, Department of Neuroscience, United States
| | - Bita Moghaddam
- University of Pittsburgh, Department of Neuroscience, United States.
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Loos M, Mueller T, Gouwenberg Y, Wijnands R, van der Loo RJ, Birchmeier C, Smit AB, Spijker S. Neuregulin-3 in the mouse medial prefrontal cortex regulates impulsive action. Biol Psychiatry 2014; 76:648-55. [PMID: 24703509 DOI: 10.1016/j.biopsych.2014.02.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 01/24/2014] [Accepted: 02/11/2014] [Indexed: 02/06/2023]
Abstract
BACKGROUND A deficit in impulse control is a prominent, heritable symptom in several psychiatric disorders, such as addiction, attention-deficit/hyperactivity disorder, and schizophrenia. Here, we aimed to identify genes regulating impulsivity, specifically of impulsive action, in mice. METHODS Using the widely used 5-choice serial reaction time task, we measured impulsive action in 1) a panel of 41 BXD recombinant inbred strains of mice (n = 13.7 ± .8 per strain; n = 654 total) to detect underlying genetic loci; 2) congenic mice (n = 23) to replicate the identified locus; 3) mice overexpressing the Nrg3 candidate gene in the medial prefrontal cortex (n = 21); and 4) a Nrg3 loss-of-function mutant (n = 59) to functionally implicate the Nrg3 candidate gene in impulsivity. RESULTS Genetic mapping of impulsive action in the BXD panel identified a locus on chromosome 14 (34.5-41.4 Mb), syntenic with the human 10q22-q23 schizophrenia-susceptibility locus. Congenic mice carrying the impulsivity locus (Impu1) confirmed its influence on impulsive action. Increased impulsivity was associated with increased Nrg3 gene expression in the medial prefrontal cortex (mPFC). Viral overexpression of Nrg3 in the mPFC increased impulsivity, whereas a constitutive Nrg3 loss-of-function mutation decreased it. CONCLUSIONS The causal relation between Nrg3 expression in the mPFC and level of impulsive action shown here provides a mechanism by which polymorphism in NRG3 in humans contributes to a specific cognitive deficit seen in several psychiatric diseases, such as addiction, attention-deficit/hyperactivity disorder, and schizophrenia.
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Affiliation(s)
- Maarten Loos
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam; Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - Thomas Mueller
- Department of Developmental Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Yvonne Gouwenberg
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam
| | - Ruud Wijnands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam; Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - Rolinka J van der Loo
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam; Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | | | - Carmen Birchmeier
- Department of Developmental Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam
| | - Sabine Spijker
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam.
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Sujan AC, Humphreys KL, Ray LA, Lee SS. Differential association of child abuse with self-reported versus laboratory-based impulsivity and risk-taking in young adulthood. CHILD MALTREATMENT 2014; 19:145-155. [PMID: 25034226 DOI: 10.1177/1077559514543827] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Young adults (ages 18-26) with (n = 20) and without (n = 55) a history of child abuse (CA) completed self-report and laboratory-based measures of impulsivity and risk-taking. Relative to individuals without abuse histories, individuals with a history of CA self-reported a greater number of lifetime sexual partners as well as elevated trait impulsivity (specifically, elevated lack of premeditation and lack of perseverance). No group differences were observed for self-reported safety-related behaviors and risk-taking propensity. Notably, however, laboratory-based measures suggested that individuals with a history of CA showed significantly less impulsivity and risk-taking than individuals without abuse histories. These results suggest that self-report and laboratory measures of risk-taking and impulsivity measured in emerging adulthood may differentially relate to CA. Specifically, whereas laboratory-based measures may be influenced by hypervigilance or in the moment actions, self-report measures may assess more general behaviors related to real-world impulsivity and risk-taking.
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Affiliation(s)
- Ayesha C Sujan
- Tulane University School of Medicine, New Orleans, LA, USA
| | - Kathryn L Humphreys
- Tulane University School of Medicine, New Orleans, LA, USA University of California, Los Angeles, CA, USA
| | - Lara A Ray
- University of California, Los Angeles, CA, USA
| | - Steve S Lee
- University of California, Los Angeles, CA, USA
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Leung CM, Stone WS, Lee EHM, Seidman LJ, Chen EYH. Impaired facilitation of self-control cognition by glucose in patients with schizophrenia: a randomized controlled study. Schizophr Res 2014; 156:38-45. [PMID: 24731620 DOI: 10.1016/j.schres.2014.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 03/15/2014] [Accepted: 03/16/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Studies in healthy individuals show that exerting self-control consumes cognitive resources, which reduces subsequent self-control performance. Restoring the availability of blood glucose eliminates this impairment. Patients with schizophrenia are found to have self-regulatory dysfunctions. This study aims to investigate whether patient's (a) glucose facilitation effects will be impaired, and (b) will have exaggerated depletion in a self-control task. METHOD 40 patients with schizophrenia-spectrum disorders and 40 normal controls were recruited. A two drinks (glucose vs. placebo)×two depleting phases (self-control depleted vs. non-depleted) between-groups design was used. We examined the blood glucose levels before and after the selfcontrol depletion phase and the subsequent performances in two self-control tasks (handgrip and Stroop tests) after the drink condition. RESULTS The four groups (depleting×glucose, depleting×placebo, non-depleting×glucose and nondepleting×placebo) of both patients and normal controls were comparable on a number of characteristics. The change in blood glucose level in the depleting group was significantly different from those in the non-depleting group. Two×two between-subjects ANOVAs were carried out to test the performances in the handgrip and Stroop tasks. Significant interactions were found in healthy controls regarding both tasks. However, a significant interaction was only found in patients regarding the handgrip task but not the Stroop task. CONCLUSIONS This study demonstrated an abnormal glucose facilitation effect in patients during a cognitive self-control task but not during a physical self-control task. The findings also suggested for the first time that a self-control depletion effect is intact in patients with schizophrenia.
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Affiliation(s)
| | - William S Stone
- Department of Psychiatry, Massachusetts Mental Health Center, Division of Public Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, United States
| | | | - Larry J Seidman
- Department of Psychiatry, Massachusetts Mental Health Center, Division of Public Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, United States; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States
| | - Eric Yu-Hai Chen
- Department of Psychiatry, University of Hong Kong, Hong Kong; State Key Laboratory of Brain and Cognitive Sciences, University of Hong Kong, Hong Kong.
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Impulsivity and risk taking in bipolar disorder and schizophrenia. Neuropsychopharmacology 2014; 39:456-63. [PMID: 23963117 PMCID: PMC3870783 DOI: 10.1038/npp.2013.218] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 12/19/2022]
Abstract
Impulsive risk taking contributes to deleterious outcomes among clinical populations. Indeed, pathological impulsivity and risk taking are common in patients with serious mental illness, and have severe clinical repercussions including novelty seeking, response disinhibition, aggression, and substance abuse. Thus, the current study seeks to examine self-reported impulsivity (Barratt Impulsivity Scale) and performance-based behavioral risk taking (Balloon Analogue Risk Task) in bipolar disorder and schizophrenia. Participants included 68 individuals with bipolar disorder, 38 with schizophrenia, and 36 healthy controls. Self-reported impulsivity was elevated in the bipolar group compared with schizophrenia patients and healthy controls, who did not differ from each other. On the risk-taking task, schizophrenia patients were significantly more risk averse than the bipolar patients and controls. Aside from the diagnostic group differences, there was a significant effect of antipsychotic (AP) medication within the bipolar group: bipolar patients taking AP medications were more risk averse than those not taking AP medications. This difference in risk taking because of AP medications was not explained by history of psychosis. Similarly, the differences in risk taking between schizophrenia and bipolar disorder were not fully explained by AP effects. Implications for clinical practice and future research are discussed.
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Huddy VC, Clark L, Harrison I, Ron MA, Moutoussis M, Barnes TRE, Joyce EM. Reflection impulsivity and response inhibition in first-episode psychosis: relationship to cannabis use. Psychol Med 2013; 43:2097-2107. [PMID: 23339857 DOI: 10.1017/s0033291712003054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND People with psychosis demonstrate impaired response inhibition on the Stop Signal Task (SST). It is less clear if this impairment extends to reflection impulsivity, a form of impulsivity that has been linked to substance use in non-psychotic samples. METHOD We compared 49 patients with first-episode psychosis (FEP) and 30 healthy control participants on two forms of impulsivity measured using the Information Sampling Test (IST) and the SST, along with clinical and IQ assessments. We also compared those patients who used cannabis with those who had either given up or never used. RESULTS Patients with FEP had significantly greater impairment in response inhibition but not in reflection impulsivity compared with healthy controls. By contrast, patients who reported current cannabis use demonstrated greater reflection impulsivity than those that had either given up or never used, whereas there were no differences in response inhibition. CONCLUSIONS These data suggest that abnormal reflection impulsivity is associated with substance use in psychosis but not psychosis itself ; the opposite relationship may hold for response inhibition.
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Affiliation(s)
- V C Huddy
- Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK
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Neural substrates underlying effort computation in schizophrenia. Neurosci Biobehav Rev 2013; 37:2649-65. [PMID: 24035741 DOI: 10.1016/j.neubiorev.2013.09.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/16/2013] [Accepted: 09/03/2013] [Indexed: 11/23/2022]
Abstract
The lack of initiative, drive or effort in patients with schizophrenia is linked to marked functional impairments. However, our assessment of effort and motivation is crude, relying on clinical rating scales based largely on patient recall. In order to better understand the neurobiology of effort in schizophrenia, we need more rigorous measurements of this construct. In the behavioural neuroscience literature, decades of work has been carried out developing various paradigms to examine the neural underpinnings of an animal's willingness to expend effort for a reward. Here, we shall review this literature on the nature of paradigms used in rodents to assess effort, as well as those used in humans. Next, the neurobiology of these effort-based decisions will be discussed. We shall then review what is known about effort in schizophrenia, and what might be inferred from experiments done in other human populations. Lastly, we shall discuss future directions of research that may assist in shedding light on the neurobiology of effort cost computations in schizophrenia.
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Simon NW, Beas BS, Montgomery KS, Haberman RP, Bizon JL, Setlow B. Prefrontal cortical-striatal dopamine receptor mRNA expression predicts distinct forms of impulsivity. Eur J Neurosci 2013; 37:1779-88. [PMID: 23510331 DOI: 10.1111/ejn.12191] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/01/2013] [Accepted: 02/17/2013] [Indexed: 12/31/2022]
Abstract
Variation in dopamine receptor levels has been associated with different facets of impulsivity. To further delineate the neural substrates underlying impulsive action (inability to withhold a prepotent motor response) and impulsive choice (delay aversion), we characterised rats in the Differential Reinforcement of Low Rates of Responding task and a delay discounting task. We also measured performance on an effort-based discounting task. We then assessed D1 and D2 dopamine receptor mRNA expression in subregions of the prefrontal cortex and nucleus accumbens using in situ hybridisation, and compared these data with behavioral performance. Expression of D1 and D2 receptor mRNA in distinct brain regions was predictive of impulsive action. A dissociation within the nucleus accumbens was observed between subregions and receptor subtypes; higher D1 mRNA expression in the shell predicted greater impulsive action, whereas lower D2 mRNA expression in the core predicted greater impulsive action. We also observed a negative correlation between impulsive action and D2 mRNA expression in the prelimbic cortex. Interestingly, a similar relationship was present between impulsive choice and prelimbic cortex D2 mRNA, despite the fact that behavioral indices of impulsive action and impulsive choice were uncorrelated. Finally, we found that both high D1 mRNA expression in the insular cortex and low D2 mRNA expression in the infralimbic cortex were associated with willingness to exert effort for rewards. Notably, dopamine receptor mRNA in these regions was not associated with either facet of impulsivity. The data presented here provide novel molecular and neuroanatomical distinctions between different forms of impulsivity, as well as effort-based decision-making.
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Affiliation(s)
- Nicholas W Simon
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Soeiro-De-Souza MG, Stanford MS, Bio DS, Machado-Vieira R, Moreno RA. Association of the COMT Met¹⁵⁸ allele with trait impulsivity in healthy young adults. Mol Med Rep 2013; 7:1067-72. [PMID: 23440431 DOI: 10.3892/mmr.2013.1336] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 02/20/2013] [Indexed: 11/05/2022] Open
Abstract
Dopamine (DA) is considered to be an important neurotransmitter in the control of impulsive behavior, however, its underlying mechanisms have not been fully elucidated. Catechol-O-methyltransferase (COMT) is a key enzyme in the catabolism of DA within the prefrontal cortex (PFC) and has been suggested to play a role in the mediation of impulsive behavior. The COMT single nucleotide polymorphism (SNP) rs4680 (Val158Met) Met allele has been shown to decrease COMT enzyme activity and is associated with improved PFC cognitive function (intelligence and executive functions). Studies have associated the rs4680 genotype with impulsivity as a symptom in attention deficit hyperactivity disorder and substance abuse. However, only a few studies have assessed the effects of rs4680 on impulsiveness in healthy subjects, the results of which remain controversial. The Barratt Impulsiveness Scale (BIS-11) was applied to 82 healthy volunteers (including 42 females) who were genotyped for COMT rs4680. Subjects carrying the Met/Met genotype scored higher for the BIS-11 second-order factor Non-planning than carriers of the Val/Val genotype. No interaction between gender genotype was detected. Age, gender and education had no effect on the results. The COMT rs4680 Met/Met genotype was associated with higher impulsivity on the BIS-11 second-order factor Non-planning. These results suggest that COMT enzyme activity may be important in the regulation of impulsiveness among young adults. Further studies involving larger samples should be conducted to confirm the results of the present study.
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Affiliation(s)
- Márcio Gerhardt Soeiro-De-Souza
- Mood Disorders Unit (GRUDA), Department and Institute of Psychiatry, School of Medicine, University of São Paulo (HC-FMUSP), São Paulo, Brazil.
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Pardey MC, Kumar NN, Goodchild AK, Cornish JL. Catecholamine receptors differentially mediate impulsive choice in the medial prefrontal and orbitofrontal cortex. J Psychopharmacol 2013; 27:203-12. [PMID: 23135240 DOI: 10.1177/0269881112465497] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Impulsivity is characteristic of several mental health disorders and is largely mediated by the prefrontal cortex subregions: the medial prefrontal cortex (mPFC) and the orbitofrontal cortex (OFC). Dopamine (DA) and norepinephrine (NE) are known to modulate activity of the prefrontal cortex, however their direct role in impulsive choice is not known. The aim of the present study was to investigate the effect of microinjecting DA or NE compounds in the mPFC or OFC on impulsive choice as measured by a delayed reinforcement (DR) task in male Wistar Kyoto rats. Following training in the DR task, rats were pretreated with DA D(1) and D(2) receptor antagonists (SCH23390 3 μg/side, raclopride 3 or 6 μg/side) or NE α(1) and α(2) receptor agonists (phenylephrine 0.1 or 0.3 μg/side, guanfacine 1 or 3 μg/side, respectively) into the mPFC or OFC and the effect on impulsive behavior was assessed. Pretreatment with raclopride into the mPFC or OFC significantly increased impulsive choice, however only pretreatment with SCH23390 into the mPFC, and not the OFC, significantly increased impulsive choice. Pretreatment with the NE receptor agonists had no effect on impulsive choice. This study suggests that DA receptors, but not NE receptors, differentially mediate impulsive choice in sub-regions of the prefrontal cortex.
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Affiliation(s)
- Margery C Pardey
- Department of Psychology, Macquarie University, Sydney, Australia
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Humpston CS, Wood CM, Robinson ESJ. Investigating the roles of different monoamine transmitters and impulse control using the 5-choice serial reaction time task. J Psychopharmacol 2013; 27:213-21. [PMID: 23135241 DOI: 10.1177/0269881112466182] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Previous studies have shown that drugs which block the reuptake of catecholamine neurotransmitters improve impulse control in diseases such as attention deficit hyperactivity disorder (ADHD). Serotonin-specific reuptake inhibitors (SSRI) lack efficacy in ADHD and have been linked to increased suicide risk. The present study investigated drugs with affinity for one or more of the monoamine reuptake transporters using the 5-choice serial reaction time task, a model of attention and impulsivity in rodents. We also tested the effects of the alpha(2)-adreoceptor antagonist, idazoxan and novel antidepressant, agomelatine, which both increase cortical noradrenaline concentrations through non-reuptake mechanisms. Improvements in impulse control were observed with venlafaxine, a serotonin and noradrenaline re-uptake inhibitor (SNRI) but not bupropion (dopamine and noradrenaline re-uptake inhibitor). Sibutramine (SNRI) reduced premature responses by ~50% at the highest dose tested but this was not significant. All three of the SSRIs tested reduced premature responding in a dose-dependent manner, although also slowed response and collection latencies. Neither idazoxan nor agomelatine significantly reduced premature responding, suggesting a lack of efficacy at the doses tested. None of the drugs tested improved attention in this task but sibutramine (SNRI), fluoxetine (SSRI) and paroxetine (SSRI) all increased omissions at the highest dose tested. These data suggest that the SNRIs and SSRIs reduce premature responding but tend to be less specific than noradrenaline specific reuptake inhibitors in this model. SSRIs did not induce any specific impairment in impulse control in this model.
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Affiliation(s)
- Clara S Humpston
- School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
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Coccaro EF, Lee R, Liu T, Mathé AA. Cerebrospinal fluid neuropeptide Y-like immunoreactivity correlates with impulsive aggression in human subjects. Biol Psychiatry 2012; 72:997-1003. [PMID: 22985695 DOI: 10.1016/j.biopsych.2012.07.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 07/24/2012] [Accepted: 07/25/2012] [Indexed: 12/23/2022]
Abstract
BACKGROUND Neurochemical studies have pointed to a modulatory role in human aggression for a number of central neurotransmitters; some (e.g., serotonin) appear to play an inhibitory role, while others (e.g., vasopressin) appear to play a facilitator role in the modulation of aggression. While recent animal studies of neuropeptide Y (NPY) have suggested a facilitator role for central NPY in the modulation of aggression, no human studies of central NPY have yet been reported regarding aggression. METHODS Basal lumbar cerebrospinal fluid (CSF) was obtained from 60 physically healthy subjects with personality disorder (PD) (n=40) and from healthy volunteers (n=20). These samples were then assessed for CSF NPY-like immunoreactivity (NPY-LI) and other neurotransmitter-related species in CSF and correlated with measures of aggression and impulsivity. RESULTS Cerebrospinal fluid NPY-LI was higher in PD subjects compared with healthy volunteers and in subjects with intermittent explosive disorder compared with those without intermittent explosive disorder. In PD subjects, CSF NPY-LI was directly correlated with composite measures of aggression and impulsivity and a composite measure of impulsive aggression. Group differences in CSF NPY-LI concentration were accounted for by measures of impulsive aggression. CONCLUSIONS These data suggest a direct relationship between CSF NPY-immunoreactivity concentration and measures of impulsive aggression in human subjects. This adds to the complex picture of the central neuromodulatory role of impulsive aggression in human subjects.
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Affiliation(s)
- Emil F Coccaro
- Department of Psychiatry and Behavioral Neuroscience, Clinical Neuroscience Research Unit, Pritzker School of Medicine, The University of Chicago, Chicago, IL 60637, USA.
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Pap D, Gonda X, Molnar E, Lazary J, Benko A, Downey D, Thomas E, Chase D, Toth ZG, Mekli K, Platt H, Payton A, Elliott R, Anderson IM, Deakin JFW, Bagdy G, Juhasz G. Genetic variants in the catechol-o-methyltransferase gene are associated with impulsivity and executive function: relevance for major depression. Am J Med Genet B Neuropsychiatr Genet 2012; 159B:928-40. [PMID: 23008195 DOI: 10.1002/ajmg.b.32098] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 08/20/2012] [Indexed: 12/23/2022]
Abstract
The catechol-o-methyltransferase (COMT) gene has been extensively investigated in depression with somewhat contradictory results but the role of impulsivity, as a possible intermediate phenotype in this disorder, has not been considered yet. In our study, four tagging SNPs in the COMT gene (rs933271, rs740603, rs4680, rs4646316) were genotyped in two independent population cohorts: Manchester (n = 1267) and Budapest (n = 942). First, we investigated the association between COMT genotypes, impulsivity, neuroticism and depression using haplotype trend regression, and constructed a model using structural equation modeling to investigate the interaction between these factors. Secondly, we tested the effect of executive function on this model in a smaller interviewed sample (n = 207). Our results demonstrated that COMT haplotypes were significantly associated with impulsivity in the combined cohort, showing the same direction of effects in both populations. The COMT effect on depressive symptoms (in subjects without history of depression) and on executive function (interviewed sample) showed the opposite pattern to impulsivity. Structural equation models demonstrated that COMT and impulsivity acted, both together (through neuroticism) and independently, to increase the risk of depression. In addition, better executive function also operated as a risk factor for depression, possibly though reduced ability to flexibly disengage negative emotions. In conclusion, variations in the COMT gene exert complex effects on susceptibility to depression involving various intermediate phenotypes, such as impulsivity and executive function. These findings emphasise that modeling of disease pathways at phenotypic level are valuable for identifying genetic risk factors.
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Affiliation(s)
- Dorottya Pap
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary
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Abstract
Reducing the risk of violent and aggressive behaviour in patients with schizophrenia remains a clinical priority. There is emerging evidence to suggest that the second-generation antipsychotic, clozapine, is effective at reducing this risk in patients with schizophrenia and some evidence to suggest that it may be best in selected patients. We conducted a systematic literature search in March 2011 of all prospective and retrospective studies, which investigated clozapine's anti-aggressive effects in a variety of mental disorders. The review identified six animal studies, four randomized controlled trials, 12 prospective non-controlled studies and 22 retrospective studies, with four case studies. We found considerable evidence in support of clozapine's ability to reduce violent and aggressive behaviour. Clozapine's anti-aggressive effect was most commonly explored in patients with schizophrenia, with less evidence available for other psychiatric disorders, including borderline personality disorder, autistic spectrum disorders, post-traumatic stress disorder, bipolar disorder and learning disability. There was mixed evidence to address the question of whether or not clozapine was any more effective than other antipsychotics. In the case of schizophrenia, there was evidence to suggest that clozapine's anti-aggressive effect was more marked particularly in those with treatment-resistant illness. Its anti-aggressive effects appeared to be 'specific', being to some extent greater than both its more general antipsychotic and sedative effects. There were significant methodological inconsistencies in the studies we identified, particularly surrounding patient recruitment criteria, the definition and measurement of violence and the lack of randomized, controlled trials. Data on therapeutic monitoring were also limited. Clozapine can reduce violence and persistent aggression in patients with schizophrenia and other psychiatric disorders. It may offer an advantage over other antipsychotics, although perhaps exclusively in the case of traditionally defined 'treatment resistance' or more broadly defined 'complex cases' with co-morbidity. Larger, randomized, blinded, controlled studies with robust characterization of participants, and standardized measures of violence and aggression are, however, needed to fully understand this link and explore the possible mechanisms.
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