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Sorkhou M, Rabin RA, Rabin JS, Kloiber S, McIntyre RS, George TP. Effects of 28 days of cannabis abstinence on cognition in major depressive disorder: A pilot study. Am J Addict 2022; 31:454-462. [PMID: 35690891 DOI: 10.1111/ajad.13305] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Cannabis is a widely used substance that may impair select cognitive domains, including attention and memory. Problematic cannabis use is a common clinical problem among patients with major depressive disorder (MDD). Few studies have investigated the effects of cannabis abstinence on cognition in MDD. Thus, our study aimed to determine whether a 28-day period of cannabis abstinence is associated with improvements in cognition in patients with MDD and comorbid cannabis use disorder (CUD). METHODS We evaluated the effects of 28 days of cannabis abstinence on cognition in MDD patients with comorbid CUD facilitated by contingency management, motivational interviewing, psychoeducation, and coping-skills training (N = 11). Primary outcomes included Baseline to Day 28 changes in verbal memory and learning, while secondary outcomes included Baseline to Day 28 changes in working memory, visuospatial working memory (VSWM), visual search speed, mental flexibility, response inhibition, attention, manual dexterity, and fine motor movement. RESULTS Eight participants (72.7%) met the pre-specified criteria for cannabis abstinence and three participants significantly reduced their cannabis use (≥90%). Visual search speed, selective attention, and VSWM improved over the study period. These improvements were not associated with changes in cannabis metabolite levels from baseline to endpoint. DISCUSSION AND CONCLUSIONS Our findings suggest that 28 days of cannabis abstinence may improve select cognitive domains in patients with MDD and comorbid CUD. SCIENTIFIC SIGNIFICANCE This is the first study to longitudinally examine the effects of cannabis on cognition in MDD. CLINICAL TRIAL Effects of Cannabis Abstinence on Symptoms and Cognition in Depression (NCT03624933; https://www. CLINICALTRIALS gov).
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Affiliation(s)
- Maryam Sorkhou
- Institute of Medical Sciences (IMS), Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Centre for Complex Interventions, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Rachel A Rabin
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Jennifer S Rabin
- Division of Neurology, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.,Harquail Centre for Neuromodulation, Sunnybrook Research Institute, Toronto, Ontario, Canada.,Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
| | - Stefan Kloiber
- Institute of Medical Sciences (IMS), Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Adult Psychiatry and Health Systems Division, CAMH, Toronto, Ontario, Canada
| | - Roger S McIntyre
- Institute of Medical Sciences (IMS), Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Mood Disorders Psychopharmacology Clinic, Toronto Western Hospital, Toronto, Ontario, Canada
| | - Tony P George
- Institute of Medical Sciences (IMS), Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Centre for Complex Interventions, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada.,Addictions Divisions, Centre for Complex Interventions, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
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Kozak K, Lowe DJE, George TP. Effects of Tobacco Smoking Status on Verbal Learning and Memory in Patients With Schizophrenia and Non-Psychiatric Controls. Am J Addict 2019; 28:503-511. [PMID: 31291035 DOI: 10.1111/ajad.12903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/03/2019] [Accepted: 04/20/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Patients with schizophrenia have higher rates of tobacco smoking compared to the general population. Moreover, these patients have deficits in cognition, including verbal learning and memory. However, it is not clear whether smoking status alters verbal learning and memory in schizophrenia. We examined the effects of smoking abstinence and reinstatement on verbal learning and memory in people with schizophrenia and nonpsychiatric controls and other cognitive domains as exploratory. METHODS Smoking participants (N = 28; 14 schizophrenia smokers; 14 nonpsychiatric smokers) were studied under smoking satiated, overnight abstinence and smoking reinstatement conditions. Nonsmokers ( n = 30; 15 schizophrenia nonsmokers; 15 nonpsychiatric nonsmokers) were also studied. A comprehensive cognitive battery was administered including verbal learning and memory using the Hopkins Verbal Learning Test-Revised (HVLT-R). RESULTS A 2 (diagnosis) × 2 (smoking status) repeated measures analysis of variance with time (session) as the within-subjects factor and diagnosis and smoking status as the between-subject factors was performed for HVLT-R and other cognitive outcomes. Smoking abstinence produced a decline in verbal memory of the HVLT discrimination index in smokers with schizophrenia that was partially revised by reinstatement, although trends for other HVLT measures were not statistically significant. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE Acute cigarette smoking and abstinence may selectively alter verbal learning and memory deficits in smokers with schizophrenia compared to nonpsychiatric smoking controls and nonsmokers, but additional studies are needed to confirm the preliminary findings in this small sample. (Am J Addict 2019;00:1-9).
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Affiliation(s)
- Karolina Kozak
- Institute of Medical Sciences (IMS), University of Toronto, Toronto, Canada.,Addictions Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Darby J E Lowe
- Institute of Medical Sciences (IMS), University of Toronto, Toronto, Canada.,Addictions Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Tony P George
- Institute of Medical Sciences (IMS), University of Toronto, Toronto, Canada.,Addictions Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Department of Psychiatry, Division of Brain and Therapeutics, University of Toronto, Toronto, Ontario, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Canada
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3
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Effects of Extended Cannabis Abstinence on Cognitive Outcomes in Cannabis Dependent Patients with Schizophrenia vs Non-Psychiatric Controls. Neuropsychopharmacology 2017; 42:2259-2271. [PMID: 28443616 PMCID: PMC5603819 DOI: 10.1038/npp.2017.85] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 04/10/2017] [Accepted: 04/21/2017] [Indexed: 01/12/2023]
Abstract
Cross-sectional studies of the effects of cannabis on cognition in schizophrenia have produced mixed results. Heavy and persistent cannabis use in schizophrenia is a common clinical problem, and effects of controlled abstinence from cannabis in these patients have not been carefully evaluated. The present study sought to determine the effects of cannabis abstinence on cognition in patients with schizophrenia and co-occurring cannabis dependence. We utilized a 28-day cannabis abstinence paradigm to investigate the state-dependent effects of cannabis on select cognitive outcomes in cannabis-dependent patients with schizophrenia and non-psychiatric controls. Nineteen patients and 20 non-psychiatric male cannabis-dependent participants underwent 28 days of cannabis abstinence. Cognition was assessed on day 0, 14, and 28 using a comprehensive neuropsychological battery. Clinical symptoms were assessed weekly. Abstinence was facilitated by contingency reinforcement confirmed by twice weekly urinalysis. Forty-two percent of patients and 55% of controls achieved end-point abstinence (p=0.53), which was biochemically-verified (day 28 urinary THC-COOH <20 ng/ml). In this preliminary study, schizophrenia-abstainers demonstrated improvements in Hopkins Verbal Learning Test-Revised (HVLT-R) performance over time [F(2,14)=4.73, p<0.03] (d=1.07). Lesser improvements on HVLT-R were observed in non-psychiatric control abstainers (d=0.66), and with abstinence on other cognitive test measures, in both patients and controls. Verbal memory and learning may improve in schizophrenia and control subjects with cannabis abstinence, but larger more definitive studies are needed. Our findings underscore the importance of developing effective interventions for cannabis use disorders in schizophrenia.
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Lencz T, Malhotra AK. Targeting the schizophrenia genome: a fast track strategy from GWAS to clinic. Mol Psychiatry 2015; 20:820-6. [PMID: 25869805 PMCID: PMC4486648 DOI: 10.1038/mp.2015.28] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 01/10/2015] [Accepted: 01/23/2015] [Indexed: 12/23/2022]
Abstract
The Psychiatric Genomics Consortium-Schizophrenia Workgroup (PGC-SCZ) has recently published a genomewide association study (GWAS) identifying >100 genetic loci, encompassing a total of 341 protein-coding genes, attaining genomewide significance for susceptibility to schizophrenia. Given the extremely long time (12-15 years) and expense (>$1 billion) associated with the development of novel drug targets, repurposing of drugs with known and validated targets may be the most expeditious path toward deriving clinical utility from these GWAS findings. In the present study, we examined all genes within loci implicated by the PGC-SCZ GWAS against databases of targets of both approved and registered pharmaceutical compounds. We identified 20 potential schizophrenia susceptibility genes that encode proteins that are the targets of approved drugs. Of these, we prioritized genes/targets that are of clear neuropsychiatric interest and that are also sole members of the linkage disequilibrium block surrounding a PGC-SCZ GWAS hit. In addition to DRD2, 5 genes meet these criteria: CACNA1C, CACNB2, CACNA1I, GRIN2A and HCN1. An additional 20 genes coding for proteins that are the targets of drugs in registered clinical trials, but without approved indications, were also identified. Although considerable work is still required to fully explicate the biological implications of the PGC-SCZ GWAS results, pathways related to these known, druggable targets may represent a promising starting point.
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Affiliation(s)
- T Lencz
- Division of Psychiatry Research, Zucker Hillside Hospital, Glen Oaks, NY, USA,Center for Psychiatric Neuroscience, Feinstein Institute for Medical Research, Manhasset, NY, USA,Departments of Psychiatry and Molecular Medicine, Hofstra University School of Medicine, Hempstead, NY, USA,Division of Psychiatry Research, Zucker Hillside Hospital, 75-59 263rd Street, Glen Oaks, NY 11004, USA. E-mail: or
| | - A K Malhotra
- Division of Psychiatry Research, Zucker Hillside Hospital, Glen Oaks, NY, USA,Center for Psychiatric Neuroscience, Feinstein Institute for Medical Research, Manhasset, NY, USA,Departments of Psychiatry and Molecular Medicine, Hofstra University School of Medicine, Hempstead, NY, USA,Division of Psychiatry Research, Zucker Hillside Hospital, 75-59 263rd Street, Glen Oaks, NY 11004, USA. E-mail: or
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Bumb JM, Enning F, Leweke FM. Drug repurposing and emerging adjunctive treatments for schizophrenia. Expert Opin Pharmacother 2015; 16:1049-67. [PMID: 25866122 DOI: 10.1517/14656566.2015.1032248] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Schizophrenia is a frequent disorder, which substantially impairs patients' quality of life. Moreover, the burden of illness for patients, their families and for the society, in general, is substantial. Nevertheless, the understanding of the pathophysiology of this syndrome, concise diagnostic methods and more effective and tolerable treatments are still lacking. Thus, innovative approaches and the exploration of new territories are required. AREAS COVERED An overview of repurposed drugs and emerging treatments for schizophrenia is presented, focusing on randomized, controlled trials and meta-analyses. EXPERT OPINION Despite many years of drug research, several needs in the treatment of schizophrenia including the safety and tolerability, stage-dependent and personalized approaches, as well as drug delivery and sustainability have not been addressed sufficiently. Given the current failure of a number of mechanistically new drugs, repurposed compounds may serve as alternative and/or adjunctive agents for schizophrenic patients and for treatment refractory patients in particular. Anti-inflammatory drugs (e.g., acetylsalicylic acid, celecoxib and minocycline), as well as N-acetylcysteine, a precursor of the major antioxidant glutathione, hormones (e.g., estrogen, raloxifene and oxytocin), glutamatergic (e.g., glycine and d-serine) and nicotinergic compounds, 'nutraceuticals' (e.g., ω-3 fatty acids) and cannabidiol, an endocannabinoidmodulator, represent promising agents in this field.
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Affiliation(s)
- Jan Malte Bumb
- Heidelberg University, Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim , J5, 68159 Mannheim , Germany +49 621 1703 2321 ; +49 621 1703 2325 ;
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Morisano D, Wing VC, Sacco KA, Arenovich T, George TP. Effects of tobacco smoking on neuropsychological function in schizophrenia in comparison to other psychiatric disorders and non-psychiatric controls. Am J Addict 2014; 22:46-53. [PMID: 23398226 DOI: 10.1111/j.1521-0391.2013.00313.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 03/21/2012] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Compared to the general population cigarette smoking prevalence is elevated in psychiatric disorders such as schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). These disorders are also associated with neurocognitive impairments. Cigarette smoking is associated with improved cognition in SZ. The effects of smoking on cognition in BD and MDD are less well studied. METHODS We used a cross-sectional design to study neuropsychological performance in these disorders as a function of smoking status. Subjects (N = 108) were SZ smokers (n = 32), SZ non-smokers (n = 15), BD smokers (n = 10), BD non-smokers (n = 6), MDD smokers (n = 6), MDD non-smokers (n = 10), control smokers (n = 12), and control non-smokers (n = 17). Participants completed a neuropsychological battery; smokers were non-deprived. RESULTS SZ subjects performed significantly worse than controls in select domains, while BD and MDD subjects did not differ from controls. Three verbal memory outcomes were improved in SZ smokers compared with non-smokers; smoking status did not alter performance in BD or MDD. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE These data suggest that smoking is associated with neurocognitive improvements in SZ, but not BD or MDD. Our data may suggest specificity of cigarette-smoking modulation of neurocognitive deficits in SZ.
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Affiliation(s)
- Dominique Morisano
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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Neurocognitive endophenotypes in schizophrenia: modulation by nicotinic receptor systems. Prog Neuropsychopharmacol Biol Psychiatry 2014; 52:79-85. [PMID: 23871750 PMCID: PMC3851927 DOI: 10.1016/j.pnpbp.2013.07.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 07/05/2013] [Accepted: 07/08/2013] [Indexed: 11/24/2022]
Abstract
Cigarette smoking is the leading preventable cause of death in the Western world, with a considerably higher prevalence observed in schizophrenia compared to the general population. Despite the negative health consequences of smoking heavily, it has been proposed that individuals with schizophrenia may maintain smoking behaviors to remediate symptoms associated with the disorder. Neurocognitive deficits are a core feature of schizophrenia and are present in approximately 80% of patients. Further, these deficits constitute an endophenotype of schizophrenia, as they are stable across disease phases, and are heritable. The neurocognitive deficits that are present in schizophrenia are especially debilitating, since they are associated with poor clinical and functional outcomes and community integration. Interestingly, these deficits may also constitute a vulnerability factor towards the initiation and maintenance of tobacco use. Contributing to the potential shared vulnerability between schizophrenia and tobacco dependence is a dysregulation of the nicotinic acetylcholine receptor (nAChR) system. Pre-clinical evidence has shown that nicotine affects several neurotransmitter systems, including dopamine (DA), glutamate, and γ-aminobutyric acid (GABA), and certain neuropsychological deficits associated with these neurotransmitters (reaction time, spatial working memory, sustained attention, and sensory gating) are improved after nicotine administration in patients with schizophrenia. These positive effects on neurocognition appear to be more pronounced in smokers with schizophrenia, and may be an important mechanism that explains the co-morbidity of schizophrenia and tobacco dependence.
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8
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Socio-demographic and clinical characteristics of heavy and non-heavy smokers among schizophrenia inpatients in a Chinese Han population. Psychopharmacology (Berl) 2014; 231:305-14. [PMID: 23963531 DOI: 10.1007/s00213-013-3239-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 08/01/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Despite higher smoking rates in schizophrenia, few studies have explored the clinical-demographic correlates of different amounts of smoking exposure. Little is known about the association between smoking severity and clinical phenotypes in Chinese patients with schizophrenia. MATERIALS AND METHODS We investigated differences between heavy (≥1 pack/day) and non-heavy (<1 pack/day) smoking in 550 male inpatients with schizophrenia using clinician-administered questionnaires and the Fagerstrom Test for Nicotine Dependence. They also were rated on the Positive and Negative Symptom Scale (PANSS), the Simpson and Angus Extrapyramidal Symptom Rating Scale (SAES), and the Abnormal Involuntary Movement Scale (AIMS), as well as were assayed with laboratory tests and an electrocardiogram. RESULTS Heavy smoking prevalence was approximately 31 %. Compared to the non-heavy smokers, the heavy smokers were younger, more with paranoid subtype but less with disorganized subtype schizophrenia, smoked at an earlier age, fewer getting clozapine or all atypical antipsychotics together, and were taking larger doses of antipsychotic drugs. The heavy smokers scored significantly lower on the PANSS negative symptom subscore and total score, and also on the SAES and AIMS scores than the non-heavy smokers. In addition, heavy smokers displayed longer rate-corrected electrocardiographic QT intervals, but without any significant differences in other laboratory tests. CONCLUSION Our results suggest several clinical or demographic differences between the heavy and non-heavy smoking patients with schizophrenia in a Chinese population. Heavy smoking remains a general health risk for schizophrenia.
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Nickell JR, Grinevich VP, Siripurapu KB, Smith AM, Dwoskin LP. Potential therapeutic uses of mecamylamine and its stereoisomers. Pharmacol Biochem Behav 2013; 108:28-43. [PMID: 23603417 PMCID: PMC3690754 DOI: 10.1016/j.pbb.2013.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 04/01/2013] [Accepted: 04/03/2013] [Indexed: 12/17/2022]
Abstract
Mecamylamine (3-methylaminoisocamphane hydrochloride) is a nicotinic parasympathetic ganglionic blocker, originally utilized as a therapeutic agent to treat hypertension. Mecamylamine administration produces several deleterious side effects at therapeutically relevant doses. As such, mecamylamine's use as an antihypertensive agent was phased out, except in severe hypertension. Mecamylamine easily traverses the blood-brain barrier to reach the central nervous system (CNS), where it acts as a nicotinic acetylcholine receptor (nAChR) antagonist, inhibiting all known nAChR subtypes. Since nAChRs play a major role in numerous physiological and pathological processes, it is not surprising that mecamylamine has been evaluated for its potential therapeutic effects in a wide variety of CNS disorders, including addiction. Importantly, mecamylamine produces its therapeutic effects on the CNS at doses 3-fold lower than those used to treat hypertension, which diminishes the probability of peripheral side effects. This review focuses on the pharmacological properties of mecamylamine, the differential effects of its stereoisomers, S(+)- and R(-)-mecamylamine, and the potential for effectiveness in treating CNS disorders, including nicotine and alcohol addiction, mood disorders, cognitive impairment and attention deficit hyperactivity disorder.
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Affiliation(s)
- Justin R Nickell
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.
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10
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Zhang XY, Chen DC, Xiu MH, Haile CN, Sun H, Lu L, Kosten TA, Kosten TR. Cigarette smoking and cognitive function in Chinese male schizophrenia: a case-control study. PLoS One 2012; 7:e36563. [PMID: 22570726 PMCID: PMC3343009 DOI: 10.1371/journal.pone.0036563] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/06/2012] [Indexed: 11/27/2022] Open
Abstract
Schizophrenic patients have higher smoking rates than the general population. Studies show that smoking may be a form of self-medication in an attempt to alleviate cognitive deficits in schizophrenic patients of European background. This study examined the relationships between smoking and cognitive deficits in Chinese schizophrenic patients, which have previously received little systemic study. We recruited 580 male chronic patients meeting DSM-IV criteria for schizophrenia and 175 male control subjects who were matched on age and education. The subjects completed a detailed cigarette smoking questionnaire, the Fagerstrom Test for Nicotine Dependence (FTND), and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Patients also were rated on the Positive and Negative Symptom Scale (PANSS), the Simpson and Angus Extrapyramidal Symptom Rating Scale (SAES), and the Abnormal Involuntary Movement Scale (AIMS). All five RBANS subscales except for the Visuospatial/Constructional index showed significantly lower cognitive performance for schizophrenics than normal controls. The schizophrenic smokers scored lower than the schizophrenic non-smokers on the RBANS total score and the Visuospatial/Constructional and Immediate Memory indices. Similarly, the control smokers scored lower than the control non-smokers on the RBANS total score and the Immediate Memory index . Also, the schizophrenic smokers consistently performed the poorest on the cognitive domains of the RBANS. Among the schizophrenic patients, smokers displayed significantly fewer negative symptoms than non-smokers. Using multivariate regression analysis the following variables were independently associated with the RBANS total score: years of education, PANSS negative symptom score, age at schizophrenia onset, and number of hospitalizations. Our results show that smoking is associated with significant cognitive impairment in both schizophrenic patients and normal controls, but the smokers with schizophrenia had a reduced level of negative symptoms, suggesting that the benefits of smoking for those with schizophrenia may be limited to certain aspects of a given clinical phenotype.
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Affiliation(s)
- Xiang Yang Zhang
- Institute of Psychology, Chinese Academy of Sciences, Beijing, People's Republic of China
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas, United States of America
- Beijing HuiLongGuan Hospital, Peking University, Beijing, People's Republic of China
| | - Da Chun Chen
- Beijing HuiLongGuan Hospital, Peking University, Beijing, People's Republic of China
| | - Mei Hong Xiu
- Beijing HuiLongGuan Hospital, Peking University, Beijing, People's Republic of China
| | - Colin N. Haile
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hongqiang Sun
- Beijing HuiLongGuan Hospital, Peking University, Beijing, People's Republic of China
- The National Institute on Drug Dependence, Peking University, Beijing, China
| | - Lin Lu
- The National Institute on Drug Dependence, Peking University, Beijing, China
| | - Therese A. Kosten
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas, United States of America
| | - Thomas R. Kosten
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas, United States of America
- Beijing HuiLongGuan Hospital, Peking University, Beijing, People's Republic of China
- * E-mail:
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Muscarinic and nicotinic acetylcholine receptor agonists and allosteric modulators for the treatment of schizophrenia. Neuropsychopharmacology 2012; 37:16-42. [PMID: 21956443 PMCID: PMC3238081 DOI: 10.1038/npp.2011.199] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Muscarinic and nicotinic acetylcholine (ACh) receptors (mAChRs and nAChRs) are emerging as important targets for the development of novel treatments for the symptoms associated with schizophrenia. Preclinical and early proof-of-concept clinical studies have provided strong evidence that activators of specific mAChR (M(1) and M(4)) and nAChR (α(7) and α(2)β(4)) subtypes are effective in animal models of antipsychotic-like activity and/or cognitive enhancement, and in the treatment of positive and cognitive symptoms in patients with schizophrenia. While early attempts to develop selective mAChR and nAChR agonists provided important preliminary findings, these compounds have ultimately failed in clinical development due to a lack of true subtype selectivity and subsequent dose-limiting adverse effects. In recent years, there have been major advances in the discovery of highly selective activators for the different mAChR and nAChR subtypes with suitable properties for optimization as potential candidates for clinical trials. One novel strategy has been to identify ligands that activate a specific receptor subtype through actions at sites that are distinct from the highly conserved ACh-binding site, termed allosteric sites. These allosteric activators, both allosteric agonists and positive allosteric modulators, of mAChR and nAChR subtypes demonstrate unique mechanisms of action and high selectivity in vivo, and may provide innovative treatment strategies for schizophrenia.
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Jurado-Barba R, Morales-Muñoz I, Del Manzano BÁ, Fernández-Guinea S, Caballero M, Martínez-Gras I, Rubio-Valladolid G. Relationship between measures of inhibitory processes in patients with schizophrenia: role of substance abuse disorders. Psychiatry Res 2011; 190:187-92. [PMID: 21704386 DOI: 10.1016/j.psychres.2011.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 06/03/2011] [Accepted: 06/05/2011] [Indexed: 11/26/2022]
Abstract
Disruption of prepulse inhibition of the startle response (PPI) has been widely identified in patients with schizophrenia, as well as impairment in many domains of cognitive functioning. However, there is some controversy regarding the relationship between PPI and the different neuropsychological tasks assessing inhibition. This controversy may be due to the influence of other variables, such as substance abuse. We aimed to determine whether differences in inhibition in schizophrenia subjects were related to their pattern of substance use and whether there was a correlation between the changes in each process. PPI and neuropsychological functioning were studied in three groups of subjects with schizophrenia (N=73): tobacco dependents (ToD; n=22), multiple substance abusers (MSUD; n=31) and non-substance abusers (non-SUD; n=20). All subjects were assessed using PPI and neuropsychological tests (Stroop and Wisconsin Card Sorting Test [WCST]). ToD showed better pre-attentive inhibitory function compared to the other two groups, and MSUD showed lower resistance to interference. Furthermore, significant correlations were found between PPI, Stroop, and WCST. Our data suggest that there is a relationship between the different tasks assessing inhibition in schizophrenia, being affected by substance abuse history. We also found differences in inhibition capacity depending on substance abuse in patients with schizophrenia.
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Affiliation(s)
- Rosa Jurado-Barba
- Instituto de Investigación Hospital Universitario 12 de Octubre, Madrid, Spain.
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13
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Wing VC, Bacher I, Sacco KA, George TP. Neuropsychological performance in patients with schizophrenia and controls as a function of cigarette smoking status. Psychiatry Res 2011; 188:320-6. [PMID: 21669462 PMCID: PMC5346074 DOI: 10.1016/j.psychres.2011.05.037] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 04/11/2011] [Accepted: 05/25/2011] [Indexed: 10/18/2022]
Abstract
Schizophrenia is associated with many neurocognitive deficits, some of which are improved by nicotine and cigarette smoking. To better understand the relationship between smoking and cognitive function in schizophrenia, cross-sectional assessment of neuropsychological performance as a function of smoking status (smoker or non-smoker) and smoking history (current, former or never-smoker) in clinically stable outpatients with schizophrenia and controls was evaluated. Subjects (n=140) were divided into subgroups on the basis of self-report and biochemical verification of smoking history. Current smokers with schizophrenia (n=38), former smokers with schizophrenia (n=17), never-smokers with schizophrenia (n=12), control smokers (n=31), control former smokers (n=16), and control never-smokers (n=26) were administered a comprehensive neuropsychological battery. Smokers were studied under non-deprivation conditions. Comparison of neuropsychological performance in schizophrenia and control subjects revealed significant main effects of diagnosis. Analysis of the data as a function of smoking history demonstrated that never-smokers with schizophrenia performed the poorest on measures of sustained attention, processing speed and response inhibition, when compared to the other schizophrenia subgroups. Cigarette smoking did not alter neuropsychological performance in controls. Our findings suggest that smoking status and history differentially alters neuropsychological outcomes in schizophrenia compared to non-psychiatric controls, and that never-smokers may present with more severe neurocognitive impairments.
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Affiliation(s)
- Victoria C. Wing
- Centre for Addiction and Mental Health (CAMH), Schizophrenia Program; Division of Addiction Psychiatry, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
,Address for Correspondence: Centre for Addiction and Mental Health 33 Russell St., room 1910A Toronto, Ontario, Canada, M5S2S1 Tel: (416) 535-8501 ext.4882 Fax: (416) 979 4676
| | - Ingrid Bacher
- Centre for Addiction and Mental Health (CAMH), Schizophrenia Program; Division of Addiction Psychiatry, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Kristi A. Sacco
- Program for Research in Smokers with Mental Illness (PRISM); Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Tony P. George
- Centre for Addiction and Mental Health (CAMH), Schizophrenia Program; Division of Addiction Psychiatry, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
,Program for Research in Smokers with Mental Illness (PRISM); Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
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Zhang XY, Xiu MH, Chen DC, Yang FD, Wu GY, Lu L, Kosten TA, Kosten TR. Nicotine dependence and serum BDNF levels in male patients with schizophrenia. Psychopharmacology (Berl) 2010; 212:301-7. [PMID: 20661552 DOI: 10.1007/s00213-010-1956-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 07/07/2010] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Schizophrenia is associated with a significantly high prevalence of smoking. Upregulation of neurotrophins by nicotine is well established. Accumulating evidence shows that brain-derived neurotrophic factor (BDNF) may be involved in the pathophysiology of schizophrenia. The purposes of this study were to compare BDNF levels in smokers to nonsmokers with schizophrenia and examine the association between BDNF levels and psychopathological symptoms. MATERIALS AND METHODS Serum BDNF levels were measured in 139 male inpatients with DSM-IV schizophrenia: 102 smokers and 37 nonsmokers. Symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). RESULTS The positive PANSS symptoms were lower in smokers than in nonsmokers, while the negative symptoms were lower in those who smoked more cigarettes. BDNF levels were significantly higher in smokers than in nonsmokers (p < 0.05). Higher BDNF levels correlated with fewer negative symptoms and with smoking more cigarettes. CONCLUSION The fewer positive symptoms in smokers and fewer negative symptoms in those who smoked more cigarettes may be associated with nicotine-induced upregulation of BDNF.
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Affiliation(s)
- Xiang Yang Zhang
- Center for Biological Psychiatry, Beijing HuiLongGuan Hospital, Beijing, 100096, China.
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Bacher I, Wu B, Shytle DR, George TP. Mecamylamine - a nicotinic acetylcholine receptor antagonist with potential for the treatment of neuropsychiatric disorders. Expert Opin Pharmacother 2010; 10:2709-21. [PMID: 19874251 DOI: 10.1517/14656560903329102] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mecamylamine (Inversine), the first orally available antihypertensive agent launched in the 1950s, is rarely used today for hypertension because of its widespread ganglionic side effects at antihypertensive doses (25 - 90 mg/day). However, more recent clinical studies suggest that mecamylamine is effective at much lower doses for blocking the central and peripheral effects of nicotine. Pharmacologically, mecamylamine has been well characterized as a nonselective and noncompetitive antagonist of nicotinic acetylcholine receptors (nAChRs). Because mecamylamine easily crosses the blood - brain barrier at relatively low doses (2.5 - 10 mg), it has been used by several research groups over the past two decades investigating the role of central nAChRs in the etiology and treatment of various neuropsychiatric disorders, including addiction disorders, Tourette's syndrome, schizophrenia and various cognitive and mood disorders. Two independent Phase II clinical trials recently confirmed mecamylamine's hypothesized antidepressant activity and suggest that it may be effective as an augmentation pharmacotherapy for SSRI treatment resistant major depression. These areas of investigation for mecamylamine are reviewed and recommendations for future research directions are proposed.
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Affiliation(s)
- Ingrid Bacher
- University of Toronto, Department of Psychiatry, Faculty of Medicine, Toronto, Canada.
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16
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Rabin RA, Sacco KA, George TP. Correlation of prepulse inhibition and Wisconsin Card Sorting Test in schizophrenia and controls: effects of smoking status. Schizophr Res 2009; 114:91-7. [PMID: 19656658 PMCID: PMC2752975 DOI: 10.1016/j.schres.2009.07.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 07/09/2009] [Accepted: 07/10/2009] [Indexed: 11/29/2022]
Abstract
BACKGROUND In schizophrenia, neurocognitive deficits associated with the illness are modulated by tobacco smoking. However, little is known about how smoking status modulates the relationships between neurocognitive measures in schizophrenia and healthy control subjects. OBJECTIVE The goal of this study was to evaluate the relationship between sensorimotor gating assessed by prepulse inhibition (PPI) and executive cognitive function using the Wisconsin Card Sorting Test (WCST) in schizophrenia and controls as a function of smoking status. METHOD We studied PPI and neuropsychological function in four groups (N=50); smokers with schizophrenia (SS; n=15), control smokers (CS; n=13), non-smokers with schizophrenia (SNS; n=11) and control non-smokers (CNS; n=11). RESULTS SNS demonstrated the poorest PPI, while SS showed comparably high levels of PPI to CNS. Non-psychiatric controls outperformed patients on WCST outcomes irrespective of smoking status. Several prefrontal outcome measures on the WCST (categories completed, percentage perseverative and non-perseverative errors) correlated significantly with PPI at the 60 and 120 ms prepulse intervals. In contrast, there were no significant correlations between PPI and any WCST outcomes in SNS, CS or CNS, and few significant correlations between PPI and other neuropsychological measures. DISCUSSION Our preliminary data suggests that the correlation between sensorimotor gating (PPI) and prefrontal executive cognitive functioning (WCST) is enhanced by acute cigarette smoking in schizophrenia.
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Affiliation(s)
- Rachel A. Rabin
- Schizophrenia Program, Centre for Addiction and Mental Health (CAMH)
| | - Kristi A. Sacco
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut USA 06519
| | - Tony P. George
- Schizophrenia Program, Centre for Addiction and Mental Health (CAMH)
- Division of Addiction Psychiatry, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada M5T 1R8
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut USA 06519
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17
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Moss TG, Sacco KA, Allen TM, Weinberger AH, Vessicchio JC, George TP. Prefrontal cognitive dysfunction is associated with tobacco dependence treatment failure in smokers with schizophrenia. Drug Alcohol Depend 2009; 104:94-9. [PMID: 19447570 PMCID: PMC2713364 DOI: 10.1016/j.drugalcdep.2009.04.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 04/03/2009] [Accepted: 04/07/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Patients with schizophrenia have higher rates of smoking (58-88%) than in the general population ( approximately 22%), and are more refractory to smoking cessation. These patients also exhibit numerous neurocognitive deficits, some of which may be ameliorated by cigarette smoking. The neurocognitive benefits derived from nicotine may, in turn, contribute to elevated rates of smoking and smoking persistence in schizophrenia. The present study examined the relationship between neurocognitive function and smoking cessation in schizophrenia. METHODS Treatment-seeking smokers with schizophrenia (N=58) participated in a 10-week placebo-controlled trial of sustained-release (SR) bupropion plus transdermal nicotine patch. Neuropsychological performance was evaluated in a subset of patients (n=31), prior to pharmacological treatment, using a neurocognitive battery. RESULTS Subjects were compared as a function of endpoint smoking status (Quit versus Not Quit), assessed by end of trial 7-day point prevalence abstinence, confirmed by CO level (< 10 ppm) on demographic traits, smoking, and clinical outcomes. While there were no significant baseline differences between quitters and non-quitters, non-quitters exhibited significantly greater deficits in performance on Trail Making Test, Part B (p=0.01) and on Digit Span backwards (p=0.04) compared to quitters. No associations were found between quit status and performance on other neuropsychological measures. CONCLUSIONS Our findings extend results of previous studies which suggest deficits in frontal executive function are associated with smoking cessation failure in schizophrenia. This may have implications for the development of tailored smoking cessation treatments in this population.
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Affiliation(s)
- Taryn G. Moss
- Department of Psychology, The University of Toronto, 100 St. George Street, Toronto Ontario, M5S 1A1
- Schizophrenia Program, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON Canada M5T 1R8
| | - Kristi A. Sacco
- Program for Research in Smokers with Mental Illness (PRISM), Connecticut Mental Health Center, 34 Park Street, New Haven, Connecticut, and Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA 06519
| | - Taryn M. Allen
- Duke University, Department of Psychology and Neuroscience, 9 Flowers Drive, Durham, North Carolina, USA 27708
| | - Andrea H. Weinberger
- Program for Research in Smokers with Mental Illness (PRISM), Connecticut Mental Health Center, 34 Park Street, New Haven, Connecticut, and Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA 06519
| | - Jennifer C. Vessicchio
- Program for Research in Smokers with Mental Illness (PRISM), Connecticut Mental Health Center, 34 Park Street, New Haven, Connecticut, and Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA 06519
| | - Tony P. George
- Department of Psychology, The University of Toronto, 100 St. George Street, Toronto Ontario, M5S 1A1
- Schizophrenia Program, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON Canada M5T 1R8
- Division of Addiction Psychiatry, Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, Toronto, Ontario, Canada M5T 1R8
- Program for Research in Smokers with Mental Illness (PRISM), Connecticut Mental Health Center, 34 Park Street, New Haven, Connecticut, and Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA 06519
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18
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Yip SW, Sacco KA, George TP, Potenza MN. Risk/reward decision-making in schizophrenia: a preliminary examination of the influence of tobacco smoking and relationship to Wisconsin Card Sorting Task performance. Schizophr Res 2009; 110:156-64. [PMID: 19269138 PMCID: PMC2817985 DOI: 10.1016/j.schres.2009.01.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 01/12/2009] [Accepted: 01/14/2009] [Indexed: 11/15/2022]
Abstract
BACKGROUND Individuals with schizophrenia show deficits in cognitive functioning, as evidenced by deficits on neurocognitive tasks such as the Wisconsin Card Sorting Task (WCST). Studies of risk/reward decision-making in individuals with schizophrenia have yielded mixed results, and few studies have examined systematically the relationship between these domains and their relationship with clinical factors. METHOD Thirty-two smokers with schizophrenia, ten non-smokers with schizophrenia, nine non-psychiatric non-smokers and ten non-psychiatric smokers were administered computerized versions of the Iowa Gambling Task (IGT) and the WCST. Smokers were allowed to smoke adlibitum during designated breaks in order to prevent deprivation. RESULTS Subjects with schizophrenia performed significantly worse than non-psychiatric controls on both the IGT and the WCST, and performance on these tasks was significantly correlated across subject groups. Among women with schizophrenia, smokers performed significantly better than non-smokers on the IGT. CONCLUSIONS Individuals with schizophrenia perform worse than controls on the IGT, suggesting impairments in risk/reward decision-making. Correlations between IGT and WCST performance suggest a shared element underlying task performance, such as a deficit in set-shifting or perseverance. Further research is needed to establish the relationship between cigarette smoking and IGT performance in schizophrenia.
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Affiliation(s)
- Sarah W Yip
- Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, Connecticut Mental Health Center, 2 Church Street South, Suite 215, New Haven, CT, United States.
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Abstract
This article selectively reviews research concerning nicotine's effects on cognition, including the neurobiological mechanism for these effects, task and experimental features that may be important for elucidating these effects, and why these effects may have amplified motivational significance among smokers with cognitive deficit. Nicotine has effects on various cognitive processes, though most studies in humans have focused on the amelioration of cognitive deficits experienced during drug withdrawal. The direct cognitive-enhancing effect of nicotine remains a controversial topic. The relationship between attentional and non-attentional cognitive effects of nicotine is discussed in the context of cognitive self-medication. Further research should include theory-driven examination of cognitive effects of nicotine, and develop targeted smoking cessation programs based on an improved understanding of the role of cognitive self-medication in high-risk individuals.
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Coulston CM, Perdices M, Tennant CC. The neuropsychology of cannabis and other substance use in schizophrenia: review of the literature and critical evaluation of methodological issues. Aust N Z J Psychiatry 2007; 41:869-84. [PMID: 17924240 DOI: 10.1080/00048670701634952] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Research on the neuropsychology of substance use in schizophrenia has been steadily growing over the past decade. However, significant gaps remain in the knowledge of individual substances and their relationship to cognition in the schizophrenia spectrum disorders. Approximately 65 studies to date have directly examined this relationship. Of these, approximately 20 have focused on nicotine, 15 on alcohol, 10 on cocaine, three on stimulants/hallucinogens, one on benzodiazepines, 10 on polydrug abuse, and seven on cannabis. Research on cannabis is especially lacking, given that worldwide it is the most commonly used illicit drug in schizophrenia, is used at higher rates in schizophrenia than in the general population, and makes its own unique contribution to the onset and prognosis of schizophrenia. In the present paper an overview of the neuropsychology literature on substance use in schizophrenia is presented, with special emphasis on cannabis. This incorporates a discussion of the methodological limitations inherent in these studies, and range of potential confounding variables that were not considered or controlled, providing directions for future research into the cognitive correlates of cannabis and other substance use in schizophrenia.
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Affiliation(s)
- Carissa M Coulston
- Academic Discipline of Psychological Medicine, Northern Clinical School, University of Sydney, NSW, Australia.
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Abstract
The development of medications for the treatment of nicotine dependence in patients with schizophrenia is a public health priority due to its high prevalence rates, devastating medical consequences, and difficulty to treat. It has been hypothesized that the high prevalence of nicotine dependence among patients with schizophrenia may be due to a shared neurobiological vulnerability. This shared vulnerability has been evidenced in reports showing that nicotine improves neuropsychological deficits associated with schizophrenia such as in the P50 evoked auditory potentials, spatial working memory, and attention. The common pathophysiologic pathways of smoking and schizophrenia may serve as the basis for the pharmacological evaluation of medications for the treatment of these concurrent disorders. Currently, little research of medications for the treatment of this comorbidity has been conducted. Studies have evaluated the efficacy of smoking cessation medications in patients with schizophrenia. These include the nicotine replacement therapy (patch, nasal spray) and sustained release bupropion. Others have evaluated the anti-smoking effect of medications (e.g., clozapine, haloperidol) used for the treatment of schizophrenia. In both cases, the results have not been conclusive. Newer smoking cessation approaches such as varenicline, selegiline, rimonabant, and nicotine vaccine, among others, have yet to be tested in this population. The purpose of this article is to review the results of the studies conducted to date and propose some potential pharmacotherapies based on the current knowledge of the pathophysiology of both disorders.
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Abstract
Cognitive dysfunction is a major component of schizophrenia, with deficits in executive function particularly pertinent to successful daily living and outcome. Executive deficits and negative/disorganised symptoms remain relatively resistant to amelioration by antipsychotic medication in comparison to positive symptoms. While there is a relative paucity of data on the effects of antipsychotics on specific executive deficits, atypical antipsychotics would appear to be more beneficial than typical antipsychotics at improving these functions, with muscarinic, glutamatergic and cholinergic systems variously implicated. Recent research focusing on the relationships between specific symptoms and specific executive deficits holds important implications for future psychopharmacological interventions in the area by elucidating the neural substrates and pathways which underpin schizophrenic symptomatology. This review attempts to evaluate the research thus far for the specific executive components of spatial working memory (SWM), inhibition, sustained attention and set shifting. Issues significant to future psychopharmacology in the area are discussed, with particular emphasis on the need for a greater consensus in methodology and definition executive function research in schizophrenia.
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Affiliation(s)
- Cara O'Grada
- Department of Psychiatry and Alimentary Pharmabiotic Centre, University College Cork, Ireland.
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Weinberger AH, Sacco KA, Creeden CL, Vessicchio JC, Jatlow PI, George TP. Effects of acute abstinence, reinstatement, and mecamylamine on biochemical and behavioral measures of cigarette smoking in schizophrenia. Schizophr Res 2007; 91:217-25. [PMID: 17293085 PMCID: PMC1913717 DOI: 10.1016/j.schres.2006.12.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 12/01/2006] [Accepted: 12/07/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Schizophrenics have higher rates of smoking than the general population, and more difficulty with smoking cessation. However, there has been little study of differences between schizophrenics and controls with respect to biochemical and behavioral indices of smoking. We compared smokers with schizophrenia (SS; n=27) and control smokers (CS; n=26) on smoking and psychiatric outcomes at baseline, during acute smoking abstinence and reinstatement, and with pre-treatment using the nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine (MEC) in a human laboratory setting. METHODS Biochemical (e.g., plasma nicotine) and behavioral (e.g., craving, withdrawal) outcomes were assessed at baseline, after overnight abstinence, and after smoking reinstatement during three consecutive test weeks. Each week, participants received one of three doses of MEC (0.0, 5.0, or 10.0 mg/dayx3 days) in a randomized, counterbalanced manner. RESULTS Compared to CS, SS displayed similar levels of craving and withdrawal, but higher plasma nicotine and cotinine levels, and cotinine/CPD ratio. During reinstatement, SS consumed significantly more cigarettes than CS, but MEC did not significantly alter indices of smoking, psychiatric symptoms, or cigarette consumption during reinstatement. CONCLUSIONS 1) The reinforcing effects of smoking may be increased in SS versus CS after overnight abstinence; 2) the lack of effects of nAChR antagonism may suggest that non-nicotinic components of cigarettes may contribute to the behavioral effects of smoking in both SS and CS; and 3) consistent with previous studies, SS may exhibit higher baseline levels of nicotine and cotinine, and greater extraction of nicotine per cigarette than CS.
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Affiliation(s)
- Andrea H Weinberger
- Program for Research on Smokers with Mental Illness (PRISM), Yale University School of Medicine, Department of Psychiatry, 34 Park Street, New Haven, CT 06519, USA.
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