Nicotine withdrawal and psychiatric symptoms in cigarette smokers with schizophrenia

The Neurobiological Underpinnings of Obsessive-Compulsive Symptoms in Psychosis, Translational Issues for Treatment-Resistant Schizophrenia

Almost 25% of schizophrenia patients suffer from obsessive-compulsive symptoms (OCS) considered a transdiagnostic clinical continuum. The presence of symptoms pertaining to both schizophrenia and obsessive-compulsive disorder (OCD) may complicate pharmacological treatment and could contribute to lack or poor response to the therapy. Despite the clinical relevance, no reviews have been recently published on the possible neurobiological underpinnings of this comorbidity, which is still unclear. An integrative view exploring this topic should take into account the following aspects: (i) the implication for glutamate, dopamine, and serotonin neurotransmission as demonstrated by genetic findings; (ii) the growing neuroimaging evidence of the common brain regions and dysfunctional circuits involved in both diseases; (iii) the pharmacological modulation of dopaminergic, serotoninergic, and glutamatergic systems as current therapeutic strategies in schizophrenia OCS; (iv) the recent discovery of midbrain dopamine neurons and dopamine D1- and D2-like receptors as orchestrating hubs in repetitive and psychotic behaviors; (v) the contribution of N-methyl-D-aspartate receptor subunits to both psychosis and OCD neurobiology. Finally, we discuss the potential role of the postsynaptic density as a structural and functional hub for multiple molecular signaling both in schizophrenia and OCD pathophysiology.

Nanotechnology Approaches for Enhanced CNS Drug Delivery in the Management of Schizophrenia

Schizophrenia is a neuropsychiatric disorder mainly affecting the central nervous system, presented with auditory and visual hallucinations, delusion and withdrawal from society. Abnormal dopamine levels mainly characterise the disease; various theories of neurotransmitters explain the pathophysiology of the disease. The current therapeutic approach deals with the systemic administration of drugs other than the enteral route, altering the neurotransmitter levels within the brain and providing symptomatic relief. Fluid biomarkers help in the early detection of the disease, which would improve the therapeutic efficacy. However, the major challenge faced in CNS drug delivery is the blood-brain barrier. Nanotherapeutic approaches may overcome these limitations, which will improve safety, efficacy, and targeted drug delivery. This review article addresses the main challenges faced in CNS drug delivery and the significance of current therapeutic strategies and nanotherapeutic approaches for a better understanding and enhanced drug delivery to the brain, which improve the quality of life of schizophrenia patients.

Smoking cessation for improving mental health

BACKGROUND

There is a common perception that smoking generally helps people to manage stress, and may be a form of 'self-medication' in people with mental health conditions. However, there are biologically plausible reasons why smoking may worsen mental health through neuroadaptations arising from chronic smoking, leading to frequent nicotine withdrawal symptoms (e.g. anxiety, depression, irritability), in which case smoking cessation may help to improve rather than worsen mental health.

OBJECTIVES

To examine the association between tobacco smoking cessation and change in mental health.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase, PsycINFO, and the trial registries clinicaltrials.gov and the International Clinical Trials Registry Platform, from 14 April 2012 to 07 January 2020. These were updated searches of a previously-conducted non-Cochrane review where searches were conducted from database inception to 13 April 2012.  SELECTION CRITERIA: We included controlled before-after studies, including randomised controlled trials (RCTs) analysed by smoking status at follow-up, and longitudinal cohort studies. In order to be eligible for inclusion studies had to recruit adults who smoked tobacco, and assess whether they quit or continued smoking during the study. They also had to measure a mental health outcome at baseline and at least six weeks later.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcomes were change in depression symptoms, anxiety symptoms or mixed anxiety and depression symptoms between baseline and follow-up. Secondary outcomes  included change in symptoms of stress, psychological quality of life, positive affect, and social impact or social quality of life, as well as new incidence of depression, anxiety, or mixed anxiety and depression disorders. We assessed the risk of bias for the primary outcomes using a modified ROBINS-I tool.  For change in mental health outcomes, we calculated the pooled standardised mean difference (SMD) and 95% confidence interval (95% CI) for the difference in change in mental health from baseline to follow-up between those who had quit smoking and those who had continued to smoke. For the incidence of psychological disorders, we calculated odds ratios (ORs) and 95% CIs. For all meta-analyses we used a generic inverse variance random-effects model and quantified statistical heterogeneity using I2. We conducted subgroup analyses to investigate any differences in associations between sub-populations, i.e. unselected people with mental illness, people with physical chronic diseases. We assessed the certainty of evidence for our primary outcomes (depression, anxiety, and mixed depression and anxiety) and our secondary social impact outcome using the eight GRADE considerations relevant to non-randomised studies (risk of bias, inconsistency, imprecision, indirectness, publication bias, magnitude of the effect, the influence of all plausible residual confounding, the presence of a dose-response gradient).

MAIN RESULTS

We included 102 studies representing over 169,500 participants. Sixty-two of these were identified in the updated search for this review and 40 were included in the original version of the review.  Sixty-three studies provided data on change in mental health, 10 were included in meta-analyses of incidence of mental health disorders, and 31 were synthesised narratively.  For all primary outcomes, smoking cessation was associated with an improvement in mental health symptoms compared with continuing to smoke: anxiety symptoms (SMD -0.28, 95% CI -0.43 to -0.13; 15 studies, 3141 participants; I2 = 69%; low-certainty evidence); depression symptoms: (SMD -0.30, 95% CI -0.39 to -0.21; 34 studies, 7156 participants; I2 = 69%' very low-certainty evidence);  mixed anxiety and depression symptoms (SMD -0.31, 95% CI -0.40 to -0.22; 8 studies, 2829 participants; I2 = 0%; moderate certainty evidence).  These findings were robust to preplanned sensitivity analyses, and subgroup analysis generally did not produce evidence of differences in the effect size among subpopulations or based on methodological characteristics. All studies were deemed to be at serious risk of bias due to possible time-varying confounding, and three studies measuring depression symptoms were judged to be at critical risk of bias overall. There was also some evidence of funnel plot asymmetry. For these reasons, we rated our certainty in the estimates for anxiety as low, for depression as very low, and for mixed anxiety and depression as moderate. For the secondary outcomes, smoking cessation was associated with an improvement in symptoms of stress (SMD -0.19, 95% CI -0.34 to -0.04; 4 studies, 1792 participants; I2 = 50%), positive affect (SMD 0.22, 95% CI 0.11 to 0.33; 13 studies, 4880 participants; I2 = 75%), and psychological quality of life (SMD 0.11, 95% CI 0.06 to 0.16; 19 studies, 18,034 participants; I2 = 42%). There was also evidence that smoking cessation was not associated with a reduction in social quality of life, with the confidence interval incorporating the possibility of a small improvement (SMD 0.03, 95% CI 0.00 to 0.06; 9 studies, 14,673 participants; I2 = 0%). The incidence of new mixed anxiety and depression was lower in people who stopped smoking compared with those who continued (OR 0.76, 95% CI 0.66 to 0.86; 3 studies, 8685 participants; I2 = 57%), as was the incidence of anxiety disorder (OR 0.61, 95% CI 0.34 to 1.12; 2 studies, 2293 participants; I2 = 46%). We deemed it inappropriate to present a pooled estimate for the incidence of new cases of clinical depression, as there was high statistical heterogeneity (I2 = 87%).

AUTHORS' CONCLUSIONS

Taken together, these data provide evidence that mental health does not worsen as a result of quitting smoking, and very low- to moderate-certainty evidence that smoking cessation is associated with small to moderate improvements in mental health.  These improvements are seen in both unselected samples and in subpopulations, including people diagnosed with mental health conditions. Additional studies that use more advanced methods to overcome time-varying confounding would strengthen the evidence in this area.

Acute Psychosis in Withdrawal from Nicotine Vaping in a Young Man with Comorbid Diabetic Ketoacidosis and Cannabis Use

Electronic delivery of nicotine, also termed “vaping,” has a growing evidence base suggesting potential harm through both exposure and withdrawal effects. The current report presents the case of a young man with multiple medical comorbidities, including insulin-dependent diabetes mellitus on an insulin pump and presumed Gilbert’s disease, and chronic cannabis use who experienced acute agitation with hallucinations in the context of quitting his vape pen “cold turkey” or abruptly discontinuing use without a nicotine replacement. While undergoing hospitalization for his complaint of nausea and vomiting in the context of euglycemic diabetic ketoacidosis and cannabis use, his psychotic symptoms became evident and continued until beginning a nicotine replacement patch. A few months later, the patient returned to the hospital again for nausea and vomiting in the context of euglycemic diabetic ketoacidosis and reported cannabis use, however this time without psychosis, and notably after resuming and continuing use of e-cigarette with nicotine replacement delivered on admission. This is the first reported case of acute psychosis related to abrupt vaping withdrawal and adds to the plethora of information regarding potential risks associated with electronic cigarette use.

Tobacco smoking, related harm and motivation to quit smoking in people with schizophrenia spectrum disorders

This narrative review focuses on the topic of tobacco smoking amongst people with schizophrenia spectrum disorders. We searched PubMed, PsycInfo and Scopus databases for schizophrenia spectrum disorders and smoking and included articles about the epidemiology of tobacco smoking in people with schizophrenia spectrum disorders, examining the relationship between smoking and mental health. This narrative review describes that a higher prevalence, frequency and impact of both high nicotine dependence and its harmful effects in patients with schizophrenia spectrum disorders compared with those in the general population. Despite several existent theories, the reasons for high smoking rates, the high dependence on nicotine and severity of nicotine withdrawal symptoms are not fully understood. The main aim of this paper is to inform mental health personnel and particularly clinical and health psychologists about the impact and role of tobacco smoking for smokers with schizophrenia spectrum disorders.

Cigarette smoking in long-term schizophrenia

Purpose

Cigarette smoking is a great health problem and prevalent among subjects with schizophrenia. Our aim was to investigate the prevalence and associations of cigarette smoking in patients with long-term schizophrenia.

Methods

Seven hundred and sixty schizophrenia patients were interviewed and their cigarette smoking was recorded.

Results

Smoking was more prevalent men than in women patients. In logistic regression analysis, male gender, duration of illness (DUI) from 10 to 19 years, being divorced or separated, lower education and high daily doses of neuroleptics (DDN) associated significantly with regular smoking. Heavy smoking associated, in men, with hospital treatment.

Conclusions

In schizophrenia patients, smoking is associated with long DUI, high DDN and institutional care. Interventions for cessation and/or reduction of cigarette smoking should be a part of the treatment for patients with schizophrenia.

Tobacco smoking and schizophrenia: re-examining the evidence

Tobacco smoking among people with mental illnesses can be explained by biological, psychological and social factors. The prevalence of smoking in people diagnosed with schizophrenia is higher than in people with other mental disorders and in the general population. This article explores three current hypotheses that explain this higher prevalence of smoking in schizophrenia. The first, the self-medication hypothesis, is increasingly countered by a growing body of evidence indicating that smokers experience more severe symptoms of schizophrenia. Numerous researchers have already identified smoking as a possible risk factor for the development of schizophrenia, which is the second hypothesis. The third hypothesis (shared genetic vulnerability) identifies certain genes that confer vulnerability for both schizophrenia and nicotine dependence. Understanding the reasons behind the higher prevalence of smoking among people with schizophrenia is vital in planning effective primary, secondary and tertiary smoking prevention for these individuals.

LEARNING OBJECTIVES

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The engagement of brain cytochrome P450 in the metabolism of endogenous neuroactive substrates: a possible role in mental disorders

The current state of knowledge indicates that the cerebral cytochrome P450 (CYP) plays an important role in the endogenous metabolism in the brain. Different CYP isoenzymes mediate metabolism of many endogenous substrates such as monoaminergic neurotransmitters, neurosteroids, cholesterol, vitamins and arachidonic acid. Therefore, these enzymes may affect brain development, susceptibility to mental and neurodegenerative diseases and may contribute to their pathophysiology. In addition, they can modify the therapeutic effects of psychoactive drugs at the place of their target action in the brain, where the drugs can act by affecting the metabolism of endogenous substrates. The article focuses on the role of cerebral CYP isoforms in the metabolism of neurotransmitters, neurosteroids, and cholesterol, and their possible involvement in animal behavior, as well as in stress, depression, schizophrenia, cognitive processes, learning, and memory. CYP-mediated alternative pathways of dopamine and serotonin synthesis may have a significant role in the local production of these neurotransmitters in the brain regions where the disturbances of these neurotransmitter systems are observed in depression and schizophrenia. The local alternative synthesis of neurotransmitters may be of great importance in the brain, since dopamine and serotonin do not pass the blood-brain barrier and cannot be supplied from the periphery. In vitro studies indicate that human CYP2D6 catalyzing dopamine and serotonin synthesis is more efficient in these reactions than the rat CYP2D isoforms. It suggests that these alternative pathways may have much greater significance in the human brain but confirmation of these assumptions requires further studies.

Minimal effects of prolonged smoking abstinence or resumption on cognitive performance challenge the "self-medication" hypothesis in schizophrenia

One prominent, long-standing view is that individuals with schizophrenia smoke cigarettes more than the general population to "self-medicate" cognitive deficits and other symptoms. This study tested the self-medication hypothesis by examining the effects of smoking abstinence and resumption on cognition in patients with schizophrenia. Nicotine-dependent smokers with schizophrenia (n=26) were trained on a cognitive battery and then hospitalized to achieve and maintain confirmed abstinence from smoking for ~1 week. Cognition was tested while smoking as usual (baseline), one day after smoking cessation (early abstinence), ~1 week later (extended abstinence), and within ~3 weeks of resuming smoking (resumption). The test battery included measures of processing speed, attention, conflict resolution, verbal memory, working memory, verbal fluency, and executive function to evaluate multiple cognitive domains affected by schizophrenia. Positive and negative symptoms of schizophrenia, depressive symptoms, and dyskinesia were also measured at baseline and after prolonged abstinence. There were no significant changes in global cognitive test performance with smoking cessation, abstinence, or resumption. There were small decreases in a measure of processing speed and delayed verbal recall with abstinence, but these findings failed to survive adjustments for multiple comparisons. Surprisingly, in this within subject "On-Off-Off-On" design, there were no significant effects of early or prolonged abstinence from smoking on cognitive and behavioral measures in smokers with schizophrenia. The results of this study challenge the widely held "self-medication" hypothesis of smoking and schizophrenia, question the extent of pro-cognitive effects of smoking and nicotine in schizophrenia, and support encouraging smoking cessation in schizophrenia.

Cigarette smoking and schizophrenia: a specific clinical and therapeutic profile? Results from the FACE-Schizophrenia cohort

BACKGROUND

Tobacco use is common in patients with schizophrenia (SZ) but little is known on the role of tobacco in the physiopathology or on the course of the disease. Only few studies embrace an extensive examination of clinical and therapeutic characteristics in stabilized patients. The objective of the present study was to determine the prevalence of tobacco smoking in stabilized SZ outpatients and the clinical and treatment characteristics associated with daily tobacco use in a large community-dwelling sample of patients.

METHODS

Three-hundred-and-sixty-one patients were included in the network of the FondaMental Expert Centers for Schizophrenia. Current tobacco status was self-declared.

RESULTS

53.7% were smokers. Mean age at tobacco onset was 17.2years old. In multivariate analyses, after adjustment for confounding factors, positive symptoms and mean daily antipsychotic dose were associated with a higher frequency of tobacco use (OR=1.06 95%IC[1.02-1.12], for positive symptoms, OR=1.1, 95%IC[1.02-1.18] for daily antipsychotic dose). Education level, negative symptoms, anticholinergic agents, clozapine or aripiprazole administration were independently associated with a lower frequency of tobacco use (respectively OR=0.87, 95%IC [0.79, 0.95], OR=0.95, 95%IC[0.91-0.98], OR=0.41, 95%IC[0.22-0.76], OR=0.56, 95%IC=[0.32, 0.99] and OR=0.49, 95%IC [0.26-0.91]).

CONCLUSION

The prevalence of current tobacco smoking in a French community-dwelling SZ patients is higher that observed in the general population. Patients with tobacco use present clinical and therapeutic specificities that may involve interaction between cholinergic-nicotinic and dopaminergic systems. The present study suggests that some therapeutics may improve daily smoking behavior in smokers. These results should be confirmed in longitudinal studies.

New Targets for Schizophrenia Treatment beyond the Dopamine Hypothesis

Schizophrenia has been primarily associated with dopamine dysfunction, and treatments have been developed that target the dopamine pathway in the central nervous system. However, accumulating evidence has shown that the core pathophysiology of schizophrenia might involve dysfunction in dopaminergic, glutamatergic, serotonergic, and gamma-aminobutyric acid (GABA) signaling, which may lead to aberrant functioning of interneurons that manifest as cognitive, behavioral, and social dysfunction through altered functioning of a broad range of macro- and microcircuits. The interactions between neurotransmitters can be modeled as nodes and edges by using graph theory, and oxidative balance, immune, and glutamatergic systems may represent multiple nodes interlocking at a central hub; imbalance within any of these nodes might affect the entire system. Therefore, this review attempts to address novel treatment targets beyond the dopamine hypothesis, including glutamate, serotonin, acetylcholine, GABA, and inflammatory cytokines. Furthermore, we outline that these treatment targets can be possibly integrated with novel treatment strategies aimed at different symptoms or phases of the illness. We anticipate that reversing anomalous activity in these novel treatment targets or combinations between these strategies might be beneficial in the treatment of schizophrenia.

Achieving Smoking Cessation in Individuals with Schizophrenia: Special Considerations

Premature mortality due to cardiovascular disease in those with schizophrenia is the largest lifespan disparity in the US and is growing; adults in the US with schizophrenia die, on average, 28 years earlier than those in the general population. The rate of smoking prevalence among individuals with schizophrenia is estimated to be from 64 to 79%. Smokers with schizophrenia have historically been excluded from most large nicotine-dependence treatment studies. However, converging evidence indicates that a majority of smokers with schizophrenia want to quit smoking, and that available pharmacotherapeutic smoking cessation aids are well tolerated by this population of smokers and are effective when combined with behavioral treatment. The aim of this review is to present updated evidence for safety and efficacy of smoking cessation interventions for those with schizophrenia spectrum illness. We also highlight implications of the very low abstinence rates for smokers with schizophrenia who receive placebo plus behavioral treatment in randomized trials, and review treatment approaches to address the high rate of rapid relapse observed upon pharmacologic treatment discontinuation in this population. Recommendations for monitoring for treatment-emergent nicotine withdrawal symptoms, side effects, and effects of cessation on antipsychotic medication are also provided. Smokers with schizophrenia spectrum disorders should be encouraged to quit smoking and should receive varenicline, bupropion with or without nicotine replacement therapy (NRT), or NRT, all in combination with behavioral treatment for at least 12 weeks. Maintenance pharmacotherapy may reduce relapse and improve sustained abstinence rates. Controlled trials in smokers with schizophrenia consistently show no greater rate of neuropsychiatric adverse events with pharmacotherapeutic cessation aids than with placebo.

Varenicline in Autism: Theory and Case Report of Clinical and Biochemical Changes

OBJECTIVE

To explore the potential benefits of varenicline (CHANTIX^®), a highly specific partial agonist of neuronal α4β2 nicotinic acetylcholine receptors (nAChR), for autistic symptoms, and present resulting biochemical changes in light of dopamine-related genotype.

METHODS

The clinical and biochemical changes exhibited by a 19-year-old severely autistic man following the use of low-dose varenicline in an ABA experiment of nature, and his genotype, were extracted from chart review. Clinical outcome was measured by the Ohio Autism Clinical Impression Scale and 12 relevant urine and saliva metabolites were measured by Neuroscience Laboratory.

RESULTS

With varenicline, this patient improved clinically and autonomic biochemical indicators in saliva and urine normalized, including dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), epinephrine, norepinephrine, taurine, and histamine levels. In addition, with varenicline, the dopamine D1 receptor (DRD1) antibody titer as well as the percent of baseline calmodulin-dependent protein kinase II (CaM KII) activity dropped significantly. When varenicline stopped, he deteriorated; when it was resumed, he again improved. Doses of 0.5, 1, and 2 mg daily were tried before settling on a dose of 1.5 mg daily. He has remained on varenicline for over a year with no noticeable side effects.

CONCLUSION

This report is, to the best of our knowledge, only the second to demonstrate positive effects of varenicline in autism, the first to show it in a severe case, and the first to show normalization of biochemical parameters related to genotype. As with the previous report, these encouraging results warrant further controlled research before clinical recommendations can be made.

Attenuated Positive Psychotic Symptoms in Relation to Cigarette Smoking in a Nonclinical Population

INTRODUCTION

This study explored the association between cigarette smoking and attenuated positive psychotic symptoms in a young adult nonclinical sample.

METHODS

Undergraduates (N = 930), aged 18-35 years (26.3% male), completed a battery of self-report measures assessing subthreshold psychotic symptoms, cigarette smoking behavior/dependence, and drug use.

RESULTS

Individuals endorsing a greater number of attenuated positive psychotic symptoms were more likely to be smokers. Exploratory analyses indicated that the odds of being a smoker were two times greater for those at potential higher risk for psychosis compared with individuals at lower risk. Results were consistent after adjusting for sex and other drug use.

CONCLUSIONS

In line with findings from psychotic populations, results suggest that attenuated positive psychotic symptoms, particularly those endorsed as distressing in a nonclinical, undergraduate population, are related to cigarette smoking.

IMPLICATIONS

Even in nonclinical, undergraduate populations, subthreshold psychotic symptoms are related to cigarette smoking, and cigarette smokers are twice as likely to be considered at potentially higher risk for psychosis compared with noncigarette smokers. In summary, there may be a threshold whereby psychotic symptoms confer increased risk for nicotine consumption, with endorsement of a greater number of distressing subthreshold psychotic symptoms increasing the likelihood of cigarette use.

Dyskinesia in an unmedicated adolescent with a 5-year history of tobacco use: a case report

Background

Tobacco use among mentally ill patients is approximately two to three times higher than that in the general population. Withdrawal from tobacco is a common occurrence and many authors have described various symptoms of nicotine withdrawal. Dyskinesia, however, has not been reported as one of the symptoms of nicotine withdrawal in adolescents without any psychopathology or medical illness.

Case presentation

We report a case of a 17-year-old Motswana boy of the Tswana ethnic group with primary school education and a 5-year history of tobacco use who developed dyskinesia approximately 48 hours after cessation of tobacco and had some relief with nicotine gum.

Conclusion

In addition to the documented symptoms of nicotine withdrawal, clinicians should look out for dyskinesia, which may be one of the rare symptoms of withdrawal in chronic tobacco users.

Smoking cessation and reduction in people with chronic mental illness

The high prevalence of cigarette smoking and tobacco related morbidity and mortality in people with chronic mental illness is well documented. This review summarizes results from studies of smoking cessation treatments in people with schizophrenia, depression, anxiety disorders, and post-traumatic stress disorder. It also summarizes experimental studies aimed at identifying biopsychosocial mechanisms that underlie the high smoking rates seen in people with these disorders. Research indicates that smokers with chronic mental illness can quit with standard cessation approaches with minimal effects on psychiatric symptoms. Although some studies have noted high relapse rates, longer maintenance on pharmacotherapy reduces rates of relapse without untoward effects on psychiatric symptoms. Similar biopsychosocial mechanisms are thought to be involved in the initiation and persistence of smoking in patients with different disorders. An appreciation of these common factors may aid the development of novel tobacco treatments for people with chronic mental illness. Novel nicotine and tobacco products such as electronic cigarettes and very low nicotine content cigarettes may also be used to improve smoking cessation rates in people with chronic mental illness.

The Role of Nicotine in Schizophrenia

Schizophrenia is associated with by severe disruptions in thought, cognition, emotion, and behavior. Patients show a marked increase in rates of smoking and nicotine dependence relative to nonaffected individuals, a finding commonly ascribed to the potential ameliorative effects of nicotine on symptom severity and cognitive impairment. Indeed, many studies have demonstrated improvement in patients following the administration of nicotine. Such findings have led to an increased emphasis on the development of therapeutic agents to target the nicotinic system as well as increasing the impetus to understand the genetic basis for nicotinic dysfunction in schizophrenia. The goal of this review article is to provide a critical summary of evidence for the role of the nicotinic system in schizophrenia. The first part will review the role of nicotine in normalization of primary dysfunctions and endophenotypical changes found in schizophrenia. The second part will provide a summary of genetic evidence linking polymorphisms in nicotinic receptor genes to smoking and schizophrenia. The third part will summarize attempts to treat schizophrenia using agents specifically targeting nicotinic and nicotinic receptor subtypes. Although currently available antipsychotic treatments are generally able to manage some aspects of schizophrenia (e.g., positive symptoms) they fail to address several other critically effected aspects of the disease. As such, the search for novel mechanisms to treat this disease is necessary.

The separate and combined effects of monoamine oxidase inhibition and nicotine on P50 sensory gating

INTRODUCTION

The cognitive effects of nicotine in humans remain a topic of great interest, due to the continued prevalence of cigarette smoking in society as well as the hypothesis that cognitively impaired populations such as schizophrenia patients use nicotine as a means of self-medicating against deficits of sensory gating. However, chronic smoking can predispose individuals to robust monoamine oxidase (MAO) inhibition, and thus far, the effect of MAO inhibition on human sensory gating is unknown.

METHODS

In this study, we investigated the effects of both nicotine (6-mg gum) and pharmacologically induced MAO-A inhibition via moclobemide (75 mg) on P50 event-related potential-indexed sensory gating in a sample of 24 healthy non-smoking males.

RESULTS

Ratio score (rP50) measured gating revealed significant improvement in auditory stimulus suppression after combined nicotine and MAO-A inhibition compared to placebo and to the nicotine-alone condition. This nicotine + MAO-A inhibition-induced efficient gating was consistent regardless of participants' baseline (placebo) gating efficiency, despite the observation that nicotine in the absence of MAO-A inhibition exhibited a detrimental effect on gating in participants with high baseline suppression ratios.

CONCLUSION

Nicotine and monoamine oxidase-inhibiting agents in tobacco smoke appear to exert a synergistic effect on sensory gating, which may contribute to the elevated dependence rates seen in populations with cognitive deficits such as schizophrenia.

EPA Guidance on Tobacco Dependence and Strategies for Smoking Cessation in People with Mental Illness

Tobacco dependence is the most common substance use disorder in adults with mental illness. The prevalence rates for tobacco dependence are two to four times higher in these patients than in the general population. Smoking has a strong, negative influence on the life expectancy and quality of life of mental health patients, and remains the leading preventable cause of death in this group. Despite these statistics, in some countries smokers with mental illness are disadvantaged in receiving intervention and support for their tobacco dependence, which is often overlooked or even tolerated. This statement from the European Psychiatric Association (EPA) systematically reviews the current evidence on tobacco dependence and withdrawal in patients with mental illness and their treatment. It provides seven recommendations for the core components of diagnostics and treatment in this patient group. These recommendations concern: (1) the recording process, (2) the timing of the intervention, (3) counselling specificities, (4) proposed treatments, (5) frequency of contact after stopping, (6) follow-up visits and (7) relapse prevention. They aim to help clinicians improve the care, health and well-being of patients suffering from mental illness.

Effectiveness of a multi-component Smoking Cessation Support Programme (McSCSP) for patients with severe mental disorders: study design

Only a few studies have examined the efficacy and safety of smoking cessation programmes in patients with mental disorders. The aim of this paper is to describe in detail the methodology used in the study as well as the Multi-component Smoking Cessation Support Programme in terms of pharmacological treatments and psychological interventions. An open-label 9-month follow-up study was conducted in Spain. A total of 82 clinically stable outpatients with schizophrenia, schizoaffective or bipolar disorder were enrolled. Treatment consisted of a programme specifically developed by the research team for individuals with severe mental disorders. The programme consisted of two phases: (1) weekly individual motivational therapy for 4–12 weeks, and (2) a 12-week active treatment phase. During this phase, at each study visit patients received a one- or two-week supply of medication (transdermal nicotine patches, varenicline or bupropion) with instructions on how to take it, in addition to group psychotherapy for smoking cessation. Evaluations were performed: (1) at the time of enrolment in the study, (2) during the 12-week active treatment phase of the study (weekly for the first 4 weeks and then biweekly), and (3) after the end of this phase (two follow-up assessments at weeks 12 and 24). Evaluations included: (1) smoking history, (2) substance use, (3) psychopathology, (4) adverse events, and (5) laboratory tests. The importance of this study lies in addressing a topical issue often ignored by psychiatrists: the unacceptably high rates of tobacco use in patients with severe mental disorders.

Cigarette smoking and mental illness: a study of nicotine withdrawal

OBJECTIVES

We compared prevalence, severity, and specific symptom profiles for nicotine withdrawal across categories of mental illness. We also examined the influence of nicotine withdrawal on efforts to quit smoking among those with mental illness.

METHODS

We analyzed data from 2 sources: wave 1 of the National Epidemiologic Survey on Alcohol and Related Conditions, limiting the sample to current smokers (2001-2002; n = 9913); and a 2-wave cohort telephone survey of a national sample of adult smokers (2004-2006; n = 751).

RESULTS

Mental illness was associated with a substantially greater likelihood of nicotine withdrawal syndrome; approximately 44% of nicotine withdrawal syndrome diagnoses were attributable to mental illness. Symptom profiles were highly comparable between mental illness categories, although anxiety-related symptoms were better markers of withdrawal for those with an internalizing disorder. Smokers with mental illness were motivated to quit but were less likely to be successful in their quit attempts, and both dependence and withdrawal independently accounted for this lower likelihood of success.

CONCLUSIONS

Nicotine withdrawal may be a particularly important target for intervention among those with mental illness who smoke cigarettes.

Psychosocial interventions for people with both severe mental illness and substance misuse

BACKGROUND

Even low levels of substance misuse by people with a severe mental illness can have detrimental effects.

OBJECTIVES

To assess the effects of psychosocial interventions for reduction in substance use in people with a serious mental illness compared with standard care.

SEARCH METHODS

For this update (2013), the Trials Search Co-ordinator of the Cochrane Schizophrenia Group (CSG) searched the CSG Trials Register (July 2012), which is based on regular searches of major medical and scientific databases. The principal authors conducted two further searches (8 October 2012 and 15 January 2013) of the Cochrane Database of Systematic Reviews, MEDLINE and PsycINFO. A separate search for trials of contingency management was completed as this was an additional intervention category for this update.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing psychosocial interventions for substance misuse with standard care in people with serious mental illness.

DATA COLLECTION AND ANALYSIS

We independently selected studies, extracted data and appraised study quality. For binary outcomes, we calculated standard estimates of relative risk (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis. For continuous outcomes, we calculated the mean difference (MD) between groups. For all meta-analyses we pooled data using a random-effects model. Using the GRADE approach, we identified seven patient-centred outcomes and assessed the quality of evidence for these within each comparison.

MAIN RESULTS

We included 32 trials with a total of 3165 participants. Evaluation of long-term integrated care included four RCTs (n = 735). We found no significant differences on loss to treatment (n = 603, 3 RCTs, RR 1.09 CI 0.82 to 1.45, low quality of evidence), death by 3 years (n = 421, 2 RCTs, RR 1.18 CI 0.39 to 3.57, low quality of evidence), alcohol use (not in remission at 36 months) (n = 143, 1 RCT, RR 1.15 CI 0.84 to 1.56,low quality of evidence), substance use (n = 85, 1 RCT, RR 0.89 CI 0.63 to 1.25, low quality of evidence), global assessment of functioning (n = 171, 1 RCT, MD 0.7 CI 2.07 to 3.47, low quality of evidence), or general life satisfaction (n = 372, 2 RCTs, MD 0.02 higher CI 0.28 to 0.32, moderate quality of evidence).For evaluation of non-integrated intensive case management with usual treatment (4 RCTs, n = 163) we found no statistically significant difference for loss to treatment at 12 months (n = 134, 3 RCTs, RR 1.21 CI 0.73 to 1.99, very low quality of evidence).Motivational interviewing plus cognitive behavioural therapy compared to usual treatment (7 RCTs, total n = 878) did not reveal any advantage for retaining participants at 12 months (n = 327, 1 RCT, RR 0.99 CI 0.62 to 1.59, low quality of evidence) or for death (n = 493, 3 RCTs, RR 0.72 CI 0.22 to 2.41, low quality of evidence), and no benefit for reducing substance use (n = 119, 1 RCT, MD 0.19 CI -0.22 to 0.6, low quality of evidence), relapse (n = 36, 1 RCT, RR 0.5 CI 0.24 to 1.04, very low quality of evidence) or global functioning (n = 445, 4 RCTs, MD 1.24 CI 1.86 to 4.34, very low quality of evidence).Cognitive behavioural therapy alone compared with usual treatment (2 RCTs, n = 152) showed no significant difference for losses from treatment at 3 months (n = 152, 2 RCTs, RR 1.12 CI 0.44 to 2.86, low quality of evidence). No benefits were observed on measures of lessening cannabis use at 6 months (n = 47, 1 RCT, RR 1.30 CI 0.79 to 2.15, very low quality of evidence) or mental state (n = 105, 1 RCT, Brief Psychiatric Rating Scale MD 0.52 CI -0.78 to 1.82, low quality of evidence).We found no advantage for motivational interviewing alone compared with usual treatment (8 RCTs, n = 509) in reducing losses to treatment at 6 months (n = 62, 1 RCT, RR 1.71 CI 0.63 to 4.64, very low quality of evidence), although significantly more participants in the motivational interviewing group reported for their first aftercare appointment (n = 93, 1 RCT, RR 0.69 CI 0.53 to 0.9). Some differences, favouring treatment, were observed in abstaining from alcohol (n = 28, 1 RCT, RR 0.36 CI 0.17 to 0.75, very low quality of evidence) but not other substances (n = 89, 1 RCT, RR -0.07 CI -0.56 to 0.42, very low quality of evidence), and no differences were observed in mental state (n = 30, 1 RCT, MD 0.19 CI -0.59 to 0.21, very low quality of evidence).We found no significant differences for skills training in the numbers lost to treatment by 12 months (n = 94, 2 RCTs, RR 0.70 CI 0.44 to 1.1, very low quality of evidence).We found no differences for contingency management compared with usual treatment (2 RCTs, n = 206) in numbers lost to treatment at 3 months (n = 176, 1 RCT, RR 1.65 CI 1.18 to 2.31, low quality of evidence), number of stimulant positive urine tests at 6 months (n = 176, 1 RCT, RR 0.83 CI 0.65 to 1.06, low quality of evidence) or hospitalisations (n = 176, 1 RCT, RR 0.21 CI 0.05 to 0.93, low quality of evidence).We were unable to summarise all findings due to skewed data or because trials did not measure the outcome of interest. In general, evidence was rated as low or very low due to high or unclear risks of bias because of poor trial methods, or poorly reported methods, and imprecision due to small sample sizes, low event rates and wide confidence intervals.

AUTHORS' CONCLUSIONS

We included 32 RCTs and found no compelling evidence to support any one psychosocial treatment over another for people to remain in treatment or to reduce substance use or improve mental state in people with serious mental illnesses. Furthermore, methodological difficulties exist which hinder pooling and interpreting results. Further high quality trials are required which address these concerns and improve the evidence in this important area.

A test of the cognitive self-medication hypothesis of tobacco smoking in schizophrenia

BACKGROUND

Heavier tobacco smoking among people with schizophrenia (SCZ) has been suggested to reflect self-medication of cognitive deficits. The idea that cognitive-enhancing effects of nicotine are a primary motivator of tobacco consumption in SCZ and that abstinence would deprive SCZ of such beneficial effects might explain hesitation among providers to pursue smoking cessation in SCZ. This study tested predictions of the cognitive self-medication hypothesis.

METHODS

In three counterbalanced sessions, 17 SCZ and 17 healthy control subjects (HCS), all smokers, were tested under ad libitum smoking or 3.5 hours after abstaining and receiving a nicotine (14 mg/24 hours) or placebo patch.

RESULTS

Attention task performance was improved by transdermal nicotine relative to placebo, with intermediate performance by ad libitum smoking. These effects were of similar size in SCZ and HCS and did not reflect remediation of functions disproportionately impaired in SCZ. Although more SCZ reported that the need to concentrate influenced their smoking, this was not reflected by the actual behavior of these patients. Self-reported ability to concentrate changed with nicotine status in HCS but not SCZ, suggesting insensitivity of SCZ to nicotine-derived performance benefits. Nicotine plasma concentrations after ad libitum smoking were not associated with performance benefits but instead with the propensity to experience nicotine withdrawal upon abstinence. This association was seen selectively in SCZ, suggesting a possible reason for heavier smoking.

CONCLUSIONS

These findings suggest that subjective or objective attentional benefits are unlikely the primary driving force of tobacco consumption in SCZ and should not discourage providers from supporting quit attempts.

Inflammatory activation and cholinergic anti-inflammatory system in eating disorders

Dysfunctional serotoninergic regulation and hypothalamic-pituitary-adrenal (HPA) axis overreactivity have been consistently reported in research studies with eating disorders (ED). In addition, the links between stress response, serotonin function, HPA axis and inflammatory mechanisms in ED have also been suggested in a number of studies. In our study, inflammatory parameters in white blood cells were investigated in 26 female patients with ED and 25 healthy control subjects matched for sex, age and ethnicity. Patients were free of medication for at least two weeks at the time of the study. Results showed a significant increase in plasma levels of the proinflammatory cytokine IL1β and the protein expression of cyclooxygenase 2 (COX2) in peripheral mononuclear blood cells (PMBCs) in ED patients compared with controls. As well as a significant increase of the oxidative-nitrosative marker TBARS (Thiobarbituric Acid Reactive Substances) in plasma. These findings were associated with increased expression of the alpha7 subunit of the nicotinic receptor (α7nAChR) in PMBC in ED patients independent of plasma cotinine levels. These results suggest that a pro-inflammatory and oxidant phenotype might be present in ED patients. Further research on cellular inflammatory and anti-inflammatory pathways might be oriented to investigate differences between ED subtypes and to search for new potential targets for pharmacological treatment.

Interventions for smoking cessation and reduction in individuals with schizophrenia

BACKGROUND

Individuals with schizophrenia smoke more heavily than the general population and this contributes to their higher morbidity and mortality from smoking-related illnesses. It remains unclear what interventions can help them to quit or to reduce smoking.

OBJECTIVES

To evaluate the benefits and harms of different treatments for nicotine dependence in schizophrenia.

SEARCH METHODS

We searched electronic databases including MEDLINE, EMBASE and PsycINFO from inception to October 2012, and the Cochrane Tobacco Addiction Group Specialized Register in November 2012.

SELECTION CRITERIA

We included randomised trials for smoking cessation or reduction, comparing any pharmacological or non-pharmacological intervention with placebo or with another therapeutic control in adult smokers with schizophrenia or schizoaffective disorder.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the eligibility and quality of trials, as well as extracted data. Outcome measures included smoking abstinence, reduction in the amount smoked and any change in mental state. We extracted abstinence and reduction data at the end of treatment and at least six months after the intervention. We used the most rigorous definition of abstinence or reduction and biochemically validated data where available. We noted any reported adverse events. Where appropriate, we pooled data using a random-effects model.

MAIN RESULTS

We included 34 trials (16 trials of cessation; nine trials of reduction; one trial of relapse prevention; eight trials that reported smoking outcomes for interventions aimed at other purposes). Seven trials compared bupropion with placebo; meta-analysis showed that cessation rates after bupropion were significantly higher than placebo at the end of treatment (seven trials, N = 340; risk ratio [RR] 3.03; 95% confidence interval [CI] 1.69 to 5.42) and after six months (five trials, N = 214, RR 2.78; 95% CI 1.02 to 7.58). There were no significant differences in positive, negative and depressive symptoms between bupropion and placebo groups. There were no reports of major adverse events such as seizures with bupropion.Smoking cessation rates after varenicline were significantly higher than placebo, at the end of treatment (2 trials, N = 137; RR 4.74, 95% CI 1.34 to 16.71). Only one trial reported follow-up at six months and the CIs were too wide to provide evidence of a sustained effect (one trial, N = 128, RR 5.06, 95% CI 0.67 to 38.24). There were no significant differences in psychiatric symptoms between the varenicline and placebo groups. Nevertheless, there were reports of suicidal ideation and behaviours from two people on varenicline.Two studies reported that contingent reinforcement (CR) with money may increase smoking abstinence rates and reduce the level of smoking in patients with schizophrenia. However, it is uncertain whether these benefits can be maintained in the longer term. There was no evidence of benefit for the few trials of other pharmacological therapies (including nicotine replacement therapy (NRT)) and psychosocial interventions in helping smokers with schizophrenia to quit or reduce smoking.

AUTHORS' CONCLUSIONS

Bupropion increases smoking abstinence rates in smokers with schizophrenia, without jeopardizing their mental state. Varenicline may also improve smoking cessation rates in schizophrenia, but its possible psychiatric adverse effects cannot be ruled out. CR may help this group of patients to quit and reduce smoking in the short term. We failed to find convincing evidence that other interventions have a beneficial effect on smoking in schizophrenia.

Impact of an electronic cigarette on smoking reduction and cessation in schizophrenic smokers: a prospective 12-month pilot study

Background: Cigarette smoking is a tough addiction to break. This dependence is the most common dual diagnosis for individuals with schizophrenia. Currently three effective drugs are approved for smoking cessation: nicotine replacement therapy (NRT), varenicline and bupropion. However, some serious side effects of varenicline have been reported, including depression, suicidal thoughts, and suicide. The use of bupropion also has side effects. It should not be used by people who have epilepsy or any condition that lowers the seizure threshold, nor by people who take a specific class of drugs called monoamine oxidase inhibitors. Hence, there are pharmacodynamic reason to believe they could precipitate or exacerbate psychosis. For its capacity to deliver nicotine and provide a coping mechanism for conditioned smoking cues by replacing some of the rituals associated with smoking gestures, electronic-cigarettes may reduce nicotine withdrawal symptoms without serious side effects. Our recent work with ECs in healthy smokers not intending to quit consistently show surprisingly high success rates. We hypothesised that these positive findings could be replicated in difficult patients with schizophrenia This tool may help smokers with schizophrenia remain abstinent during their quitting attempts or to reduce cigarette consumption. Efficacy and safety of these devices in long-term smoking cessation and/or smoking reduction studies have never been investigated for this special population. Methods: In this study we monitored possible modifications in smoking habits of 14 smokers (not intending to quit) with schizophrenia experimenting with the “Categoria” e-Cigarette with a focus on smoking reduction and smoking abstinence. Study participants were invited to attend six study visits: at baseline, week-4, week-8, week-12 week-24 and week 52. Product use, number of cigarettes smoked, carbon monoxide in exhaled breath (eCO) and positive and negative symptoms of schizophrenia levels were measured at each visit. Smoking reduction and abstinence rates were calculated. Adverse events were also reviewed. Results: Sustained 50% reduction in the number of cig/day at week-52 was shown in 7/14 (50%) participants; their median of 30 cig/day decreasing significantly to 15 cig/day (p = 0.018). Sustained smoking abstinence at week-52 was observed in 2/14 (14.3%) participants. Combined sustained 50% reduction and smoking abstinence was shown in 9/14 (64.3%) participants. Nausea was observed in 2/14 (14.4%) of participants, throat irritation in 2/14 (14.4%) of participants, headache in 2/14 (14.4%) of participants , and dry cough in 4/14 (28.6%) of participants. However, these adverse events diminished substantially by week-24. Overall, one to two cartridges/day were used throughout the study. Positive and negative symptoms of schizophrenia are not increased after smoking reduction/cessation in patients using e-cigarettes. Conclusions: We have shown for the first time that the use of e-cigarette substantially decreased cigarette consumption without causing significant side effects in chronic schizophrenic patients who smoke not intending to quit. This was achieved without negative impacts on the symptoms of schizophrenia as assessed by SAPS and SANS symptoms scales.

Optimizing cholinergic tone through lynx modulators of nicotinic receptors: implications for plasticity and nicotine addiction

The cholinergic system underlies both adaptive (learning and memory) and nonadaptive (addiction and dependency) behavioral changes through its ability to shape and regulate plasticity. Protein modulators such as lynx family members can fine tune the activity of the cholinergic system and contribute to the graded response of the cholinergic system, stabilizing neural circuitry through direct interaction with nicotinic receptors. Release of this molecular brake can unmask cholinergic-dependent mechanisms in the brain. Lynx proteins have the potential to provide top-down control over plasticity mechanisms, including addictive propensity. If this is indeed the case, then, what regulates the regulator? Transcriptional changes of lynx genes in response to pharmacological, physiological, and pathological alterations are explored in this review.

Exploring the relationships between tobacco smoking and schizophrenia in first-degree relatives

Up to 90% of individuals with schizophrenia suffer from nicotine dependence. Both schizophrenia and nicotine consumption have strong genetic components, which may overlap. The relationship between schizophrenia and nicotine dependence remains unclear, due in part to confounding factors. Studies of the relationship between nicotine consumption and milder schizophrenia-related phenotypes, such as schizotypy, in first-degree relatives of individuals with schizophrenia could help to better understand the relationship between smoking and schizophrenia while avoiding such confounders. We assessed the proportion of smokers, their level of nicotine dependence and their level of schizotypy in a sample of 98 first-degree relatives of schizophrenic subjects and 110 healthy controls. Partial correlation analysis was used to assess the relationship between schizotypal dimensions and smoking dependence. The prevalence of smoking and nicotine dependence levels were higher in the relatives than in the healthy control group. We found no relationship between nicotine dependence and the magnitude of schizotypal features in either group. Our results support the hypothesis that the relationship between schizophrenia and smoking is largely mediated by common familial factors, which may be genetic.

Nicotine fails to attenuate ketamine-induced cognitive deficits and negative and positive symptoms in humans: implications for schizophrenia

BACKGROUND

The uncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist, ketamine, induces a range of symptoms resembling those seen in schizophrenia. Enhancement of nicotinic acetylcholine receptor (nAChR) function may have potential as a treatment for the cognitive deficits and negative symptoms of schizophrenia. Accordingly, we examined the modulatory effects of brain nAChR systems on NMDAR antagonist-induced effects.

METHODS

The interactive effects of ketamine and nicotine were evaluated in 37 healthy subjects in a randomized, placebo-controlled, double-blind, crossover counterbalanced, 2 (intravenous ketamine or placebo) × 2 (intravenous nicotine or placebo) design. Verbal and visual memory, sustained attention, working memory, response inhibition, emotion recognition, executive function, reaction time, motor function, and speed of processing were assessed once per test day, while negative and positive symptoms, perceptual alterations, and a number of feeling states were measured several times before and after administration of drugs.

RESULTS

Ketamine induced cognitive deficits and negative and positive symptoms. Nicotine worsened immediate recall, auditory working memory, response inhibition, and executive function and serial processing. Nicotine decreased (improved) reaction time on the sustained attention and choice reaction time tasks. Nicotine did not reduce ketamine-induced cognitive deficits or negative and positive symptoms.

CONCLUSIONS

At blood levels comparable with tobacco smoking, nicotine infusion does not appear to alleviate the ketamine-induced transient cognitive and behavioral effects in healthy subjects that resemble those seen in schizophrenia. The lack of an effect of nicotine on a spectrum of ketamine effects suggests that the consequences of NMDAR antagonism are not likely under the direct influence of nAChR.

Risk of smoking and receipt of cessation services among veterans with mental disorders

OBJECTIVE

The purpose of this study was to determine rates of smoking and receipt of provider recommendations to quit smoking among patients with mental disorders treated in U.S. Department of Veterans Affairs (VA) treatment settings.

METHODS

The authors conducted a secondary analysis of the yearly, cross-sectional 2007 Veterans Health Administration Outpatient Survey of Healthcare Experiences of Patients (N=224,193). Logistic regression was used to determine the independent association of mental health diagnosis and the dependent variables of smoking and receipt of provider recommendations to quit smoking.

RESULTS

Patients with mental disorders had greater odds of smoking, compared with those without mental disorders (p<.05). Those with various mental disorders reported similar rates of receiving services (more than 60% to 80% reported receiving selected services), compared with those without these disorders, except that those with schizophrenia had more than 30% lower odds of receiving advice to quit smoking from their physicians (p<.05). Moreover, those who had co-occurring posttraumatic stress disorder or substance use disorders had significantly greater odds of reporting that they received advice to quit, recommendations for medications, and physician discussions of quitting methods, compared with those without these disorders (p<.05). Older patients, male patients, members of ethnic minority groups, those who were unmarried, those who were disabled or unemployed, and those living in rural areas had lower odds of receiving selected services (p<.05).

CONCLUSIONS

The majority of patients with mental disorders served by the VA reported receiving cessation services, yet their smoking rates remained high, and selected groups were at risk for receiving fewer cessation services, suggesting the continued need to disseminate cessation services.

Nicotinic mechanisms in the treatment of psychotic disorders: a focus on the α7 nicotinic receptor

Nicotine is heavily abused by persons with schizophrenia. Nicotine better enables people with schizophrenia to filter out extraneous auditory stimuli. Nicotine also improves prepulse inhibition when compared to placebo. Nicotine similarly increases the amplitude of patients' duration mismatch negativity. The 15q13-14 region of the genome coding for the α7 nicotinic receptor is linked to schizophrenia. Multiple single nucleotide polymorphisms have been identified in this 15q13-14 gene promoter region that are more frequently present in people with schizophrenia than in normal controls. Abnormalities in expression and regulation of central nicotinic cholinoceptors with decreased α7 binding in multiple brain regions are also present. Nicotine enhances cognition in schizophrenia. Alternative agents that activate the nicotinic receptor have been tested including 3-[2,4-dimethoxybenzylidene]anabaseine (DMXB-A). This compound improved attention, working memory, and negative symptoms in an add-on study in nonsmoking patients with schizophrenia. There are multiple other nicotinic agents, including positive allosteric modulators, in the preclinical stages of development. Finally, the effects of varenicline and clozapine and their relation to smoking cessation are discussed.

Varenicline prevents affective and cognitive exacerbation during smoking abstinence in male patients with schizophrenia

To explore the effects of varenicline on the psychopathology and cognition of chronic inpatients with schizophrenia, we conducted a non-randomized control group time series investigation between March 2009 and April 2010. In a mandatory smoking cessation intervention, 41 male inpatient smokers were scheduled to undergo either a 5-week varenicline treatment (varenicline group) or the use of no drugs (non-treatment group). Depression (HAM-D), anxiety (HAM-A), and psychosis (PANSS) were evaluated at baseline, and at the 2nd, 4th, 8th and 12th week after abstinence; four neuropsychological tests, including Digit Span Forward and Backward (DSF and DSB), and Trail Making Test-A and -B, were evaluated at baseline and at the 4th, 8th and 12th week. .Thirty patients completed the study. Among 15 patients in the non-treatment group, the HAM-D, HAM-A, DSF, and DSB scores were exacerbated during the 2-8 weeks of abstinence, but there were no changes in psychotic symptoms and the other two neuropsychological tests. Compared with the non-treatment group, varenicline users experienced less impairment in HAM-D and HAM-A scores at the 2nd and 4th weeks, and in DSF tasks at the 4th week after abstinence. In conclusions, varenicline can attenuate abstinence-induced adverse outcomes and appears to be well-tolerated in smokers with schizophrenia.

Smoking cessation in persons with serious mental illnesses: the experience of successful quitters

OBJECTIVE

The purpose of the study was to better understand the experiences of persons with serious mental illnesses who have quit smoking.

METHODS

Former smokers with serious mental illnesses who had been abstinent for at least 4 months participated in an individually-administered structured interview about their motivation to quit smoking and the strategies that they used to quit. Participants also were asked about their willingness to assist peers in smoking cessation.

RESULTS

The sample of 78 successful quitters had been abstinent from smoking for an average of 7.4 (±8.6) years after smoking for a mean of 25.3 (±11.4) years; the mean peak quantity of cigarettes smoked was 1.5 (± 1.1) packs per day. The primary reason for quitting smoking was health concerns, endorsed by 57 (73%) of respondents. Additional reasons included the cost of cigarettes (55, 71%); advice from a doctor (42, 54%); advice from others (50, 64%). The main methods that participants cited as enabling them to quit were social support from friends or family (cited by 45, 58%); direction from a doctor (36, 46%); use of nicotine replacement therapy (NRT) (24, 31%); and the advice of friends who had quit (18, 23%). Only a small proportion of the sample had received smoking cessation treatment other than NRT. A large portion of the sample indicated that they would be willing to serve in peer helping roles for smoking cessation.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Persons with serious mental illnesses are able to successfully quit smoking despite extensive histories of heavy smoking. For practitioners, this study also emphasizes the importance of smoking cessation programming that is relevant and easily accessible to people with serious mental illnesses. Importantly, former smokers living with mental illnesses indicated a willingness to be involved in helping others quit, and should be utilized in formal smoking cessation efforts aimed at their peers.

Cigarette smoking across the schizotypy spectrum

This study examined relationships between schizotypy symptom dimensions and smoking. Individuals with schizotypy (n=81) were twice as likely to smoke as individuals in a normative reference group (n=303). Among those with schizotypy, smokers reported more severe disorganization and less severe negative schizotypal symptoms. These findings offer insight into mechanisms underlying smoking in schizotypal individuals and suggest areas for further research.

Interventions for smoking cessation and reduction in individuals with schizophrenia

BACKGROUND

Patients with schizophrenia smoke more heavily than the general population and this contributes to their higher morbidity and mortality from smoking-related illnesses. It remains unclear what interventions can help them to quit or reduce smoking.

OBJECTIVES

To evaluate the benefits and harms of different treatments for nicotine dependence in schizophrenia.

SEARCH STRATEGY

We searched the Cochrane Tobacco Addiction Group Specialized Register and electronic databases including MEDLINE, EMBASE and PsycINFO from inception to April 2010.

SELECTION CRITERIA

We included randomized trials for smoking cessation or reduction, comparing any pharmacological or non-pharmacological intervention with placebo or with another therapeutic control in adult smokers with schizophrenia or schizoaffective disorder.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the eligibility and quality of trials and extracted data. Outcome measures included smoking abstinence, reduction in the amount smoked and any change in mental state. We extracted abstinence and reduction data at the end of treatment and at least six months after the intervention. We used the most rigorous definition of abstinence or reduction and biochemically validated data where available. Any reported adverse events were noted. Where appropriate, we pooled data using a random effects model.

MAIN RESULTS

We included 21 trials (11 trials of smoking cessation; four trials of smoking reduction; one trial for relapse prevention; five trials reported smoking outcomes for interventions aimed at other purposes). Seven trials compared bupropion with placebo; meta-analysis showed that smoking cessation rates after bupropion were significantly higher than placebo at the end of treatment (seven trials, N=340; risk ratio [RR] 2.84; 95% confidence interval [CI] 1.61 to 4.99) and after six months (five trials, N=214, RR 2.78; 95% CI 1.02 to 7.58). Expired carbon monoxide (CO) level and the number of cigarettes smoked daily were significantly lower with bupropion at the end of therapy but not after six months. There were no significant differences in positive, negative and depressive symptoms between bupropion and placebo group. There was no report of major adverse event such as seizures with bupropion.Contingent reinforcement (CR) with money may increase smoking abstinence rates and reduce the level of smoking in patients with schizophrenia. However, it is uncertain whether these benefits are maintained in the longer term. There was no evidence of benefit for the few trials of other pharmacological therapies (including nicotine replacement therapy (NRT)) and psychosocial interventions in helping smokers with schizophrenia to quit or reduce smoking.

AUTHORS' CONCLUSIONS

Bupropion increases smoking abstinence rates in smokers with schizophrenia, without jeopardising their mental state. Bupropion may also reduce the amount these patients smoke. CR may help this group of patients to quit and reduce smoking. We failed to find convincing evidence that other interventions have a beneficial effect on smoking behaviour in schizophrenia.

Mechanisms underlying the comorbidity of tobacco use in mental health and addictive disorders

We discuss potential explanations for the high prevalence of tobacco use and tobacco dependence (TD) in people with mental health and addictive (MHA) disorders. The biopsychosocial basis for this comorbidity is presented, integrating evidence from epidemiologic and clinical studies. We also review evidence that suggests a shared vulnerability related to biological, genetic, and environmental factors may be the most parsimonious mechanism to explain the association between TD and MHA disorders. Finally, we review the examples of various MHA disorders that are associated with TD, and suggest avenues for new investigation that could aid in the development of rationale and more effective treatments for tobacco and MHA disorder comorbidities.

Safety and effectiveness of varenicline in a veteran population with a high prevalence of mental illness

BACKGROUND

Varenicline is a selective nicotinic receptor partial agonist used to aid in the process of smoking cessation. Research on varenicline's approval for marketing demonstrated that after 12 weeks of treatment, at least 44% of patients successfully quit smoking and, on average, 13% of individuals discontinued therapy due to an adverse drug event (ADE). Growing postmarketing data linked varenicline to an increase in neuropsychiatric symptoms.

OBJECTIVE

To evaluate the safety profile, specifically psychiatric symptoms, and effectiveness of varenicline in a veteran population and to determine whether there is an association among specific baseline demographics and success rate.

METHODS

The study was a retrospective review of a prospective performance measure involving veterans initiated on varenicline. Patients were contacted via telephone throughout treatment and at week 12 for effectiveness follow-up. Smoking history was obtained and medication counseling was provided. The primary endpoint was tobacco cessation between weeks 9 and 12 of therapy. Varenicline's safety profile and discontinuation rates due to ADEs were also analyzed.

RESULTS

Of the 50 patients included in the study, 30% (n = 15) successfully quit smoking and 70% (n = 35) failed therapy (lack of effectiveness, n = 22; intolerability, n = 13). Prevalence of underlying mental illness in the success group (4/15; 27%) versus failure group (20/35; 57%) was statistically significant (p < 0.001). All patients who discontinued therapy due to an increase in mood and behavioral changes (n = 4) had an underlying psychiatric illness. The study results demonstrate a lower success rate and a higher incidence of discontinuation due to an ADE in our veteran population compared with premarketing data. An inverse association was shown between psychiatric disorders and success.

CONCLUSIONS

Cautious treatment initiation and close monitoring of veterans initiated on varenicline are warranted. Furthermore, the results from this study demonstrate the need for prospective effectiveness trials to determine the clinical significance of the results.

Predictors of early abstinence in smokers with schizophrenia

BACKGROUND

In patients with schizophrenia, the smoking cessation rate is low and the burden of smoking-related morbidity and mortality is high. Identification of factors associated with abstinence may allow clinicians to optimize treatment prior to a smoking cessation attempt.

METHOD

To identify factors associated with successful smoking cessation in patients with a DSM-IV diagnosis of schizophrenia, we analyzed baseline data from 114 stable outpatient smokers with schizophrenia who participated in 1 of 2 smoking cessation trials. The outcome of interest was 4 weeks' continuous abstinence at the end of a 12-week nicotine dependence treatment intervention. Baseline factors associated with abstinence were identified with univariate methods and entered into a manual, forward-selection multivariable regression model to identify independent predictors of abstinence. The study was conducted from March 1999 to February 2004.

RESULTS

Fourteen of 114 participants (12%) had biochemically verified 4 weeks' continuous abstinence at week 12. We included 10 noncorrelated variables with a univariate association with abstinence in a multivariable model, controlling for pharmacotherapy, age, and gender. Age at initiation of smoking and baseline variability in attentiveness, as measured by Continuous Performance Test-AX (CPT-AX) hit reaction time standard error, were independently associated with abstinence. For every year increase in age at initiation of smoking, the OR for abstinence was 1.36 (95% CI = 1.01 to 1.83), p = .048. For every millisecond decrease in the variability of the reaction time of CPT-AX, the OR for achieving abstinence was 1.55 (95% CI = 1.07 to 2.24), p = .021.

CONCLUSION

Later initiation of smoking was associated with increased and baseline attentional impairment with reduced odds of abstinence. Additional research to further our understanding of the relationship between attentional impairment and cigarette smoking in schizophrenia may lead to improved nicotine dependence treatments for this group.

Psychosocial interventions for people with both severe mental illness and substance misuse

BACKGROUND

Even low levels of substance misuse by people with a severe mental illness can have detrimental effects.

OBJECTIVES

To assess the effects of psychosocial interventions for substance reduction in people with a serious mental illness.

SEARCH STRATEGY

For this update (2007) we searched the Cochrane Schizophrenia Group Trials Register (May 2006) which is based on regular searches of major databases.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing psychosocial interventions for substance misuse with standard care in people with serious mental illness.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis, based on a random effects model. We calculated numbers needed to treat/harm (NNT/NNH) where data were homogeneous. For continuous data, we calculated weighted mean differences (WMD) again based on a random effects model.

MAIN RESULTS

Evaluation of long-term integrated care included 4 RCTs (total n=735). We found no significant difference on measures of substance use (n=85, 1 RCT, RR 0.89 CI 0.6 to 1.3) or loss to treatment (n=603, 3 RCTs, RR 1.09 CI 0.8 to 1.5). For the non-integrated intensive case management trials (4 RCTs, total n=151) we also found no significant difference for loss (n=134, 3 RCTs, RR 1.35 CI 0.8 to 2.2). Motivational interviewing plus cognitive behavioural therapy (3 RCTs, total n=276) did not reveal any advantage for retaining participants (n=36, 1 RCT, RR lost to treatment 0.50 CI 0.1 to 5.0) or for relapse (n=36, 1 RCT, RR 0.58 CI 0.3 to 1.1), and no benefit for reducing substance use (n=119, 1 RCT, RR 0.19 CI -0.2 to 0.6). Cognitive behavioural therapy alone (4 trials, total n=260) showed fewer participants lost from treatment (n=260, 4 RCTs, p=0.02, RR 0.61 CI 0.4 to 0.9). No benefits were observed on measures of lessening cannabis use (n=47, 1 RCT, RR 1.30 CI 0.8 to 2.2) or on the number of participants using substances (alcohol; n=46, 1 RCT, RR 5.88 CI 0.8 to 44.0, drugs; n=46, 1 RCT, RR 2.02 CI 0.9 to 4.8) and no differences were observed on measures of mental state (n=105, 1 RCT, RR 0.52 CI -0.8 to 1.8). We found no advantage for motivational interviewing alone (5 trials, total n=338) in reducing 'lost to evaluation' (n=338, 5 RCTs, RR 0.96 CI 0.6 to 1.5) compared with treatment as usual, although significantly more participants in the motivational interviewing group reported for their first aftercare appointment (n=93, 1 RCT, RR 0.69 CI 0.5 to 0.9, NNT 4 CI 3 to 12). Some differences were observed in abstaining from alcohol favouring treatment (n=28, 1 RCT, RR 0.36 CI 0.2 to 0.8, NNT 2 CI 2 to 5), but not other substances (n=89, 1 RCT, RR -0.07 CI -0.6 to 0.4) and no differences were observed in mental state (n=30, 1 RCT, WMD -4.20 CI -18.7 to 10.3). Finally, we found no significant differences for skills training in the numbers lost to treatment by 12 months (n=94, 2 RCTs, RR 0.70 CI 0.4 to 1.1).

AUTHORS' CONCLUSIONS

We included 25 RCTs and found no compelling evidence to support any one psychosocial treatment over another to reduce substance use (or improve mental state) by people with serious mental illnesses. Furthermore, methodological difficulties exist which hinder pooling and interpreting results; high drop out rates, varying fidelity of interventions, varying outcome measures, settings and samples and comparison groups may have received higher levels of treatment than standard care. Further studies are required which address these concerns and improve the evidence in this important area.

Gray matter volume differences and the effects of smoking on gray matter in schizophrenia

OBJECTIVE

Many studies have evaluated differences in gray matter volume in schizophrenia, but have not considered the possible effects of smoking, which is extraordinarily common in people with the illness. The present study used voxel-based morphometry (VBM) to examine differences in gray matter in subjects with schizophrenia and evaluate the effects of smoking on this measure.

METHODS

Thirty-two subjects with schizophrenia (14 smokers, 18 non-smokers) and 32 healthy comparison subjects participated in the study. Whole brain, voxel-wise analyses of regional gray matter volume were conducted using voxel-based morphometry (VBM).

RESULTS

Reduced gray matter was observed in the schizophrenia group in the orbitofrontal cortex, bilateral insula and superior temporal gyri (STG), bilateral dorsolateral prefrontal cortices (DLPFC), medial frontal gyrus, and cingulate gyrus. Within this group, smoking subjects had greater lateral prefrontal and STG gray matter volumes relative to non-smoking subjects.

CONCLUSIONS

The finding of reduced gray matter volume in prefrontal and temporal regions in schizophrenia is consistent with prior anatomical tracing and whole-brain voxel-based studies. Greater gray matter volumes in smoking relative to non-smoking subjects with schizophrenia highlight a potential experimental confound in volumetric studies and suggests that smoking may be associated with a relative preservation of lateral prefrontal and temporal gray matter in schizophrenia.

Smoking, Genetics and Schizophrenia: Evidence for Self Medication

Schizophrenia is a common mental illness with a high prevalence of smoking. More than 80% of schizophrenics smoke compared to 25% of the general population. Both schizophrenia and tobacco use have strong genetic components, which may overlap. It has been suggested that smoking in schizophrenia may be a form of self-medication in an attempt to treat an underlying biological pathology. Smoking normalizes auditory evoked potential and eye tracking deficits in schizophrenia, as well as improving cognitive function. Nicotine acts through a family of nicotinic receptors with either high or low affinity for nicotine. The loci for several of these receptors have been genetically linked to both smoking and to schizophrenia. Smoking changes gene expression for more than 200 genes in human hippocampus, and differentially normalizes aberrant gene expression in schizophrenia. The α7* nicotinic receptor, linked to schizophrenia and smoking, has been implicated in sensory processing deficits and is important for cognition and protection from neurotoxicity. Nicotine, however, has multiple health risks and desensitizes the receptor. A Phase I trial of DMXB-A, an α7* agonist, shows improvement in both P50 gating and in cognition, suggesting that further development of nicotinic cholinergic drugs is a promising direction in schizophrenia research.

Medications Development for the Treatment of Nicotine Dependence in Individuals with Schizophrenia

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.

Treatment consideration and manifest complexity in comorbid neuropsychiatric disorders

Psychiatric disorders may co-occur in the same individual. These include, for example, substance abuse or obsessive-compulsive disorder with schizophrenia, and movement disorders or epilepsy with affective dysfunctional states. Medications may produce iatrogenic effects, for example cognitive impairments that co-occur with the residual symptoms of the primary disorder being treated. The observation of comorbid disorders in some cases may reflect diagnostic overlap. Impulsivity, impulsiveness or impulsive behaviour is implicated in a range of diagnostic conditions including substance abuse, affective disorder and obsessive-compulsive disorder. These observations suggest a need to re-evaluate established diagnostic criteria and disorder definitions, focusing instead on symptoms and symptom-profiles.

Treating schizophrenia symptoms with an alpha7 nicotinic agonist, from mice to men

Current antipsychotic treatments fail to fully address the range of symptoms of schizophrenia, particularly with respect to social and occupational dysfunctions. Recent work has highlighted the role of nicotinie in both cognitive and attentional deficits as well as deficient processing of repetitive sensory information. The predilection for schizophrenia patients to be extremely heavy cigarette smokers may be related to their attempt to compensate for a reduction in hippocampal alpha7 nicotinic cholinergic receptors by delivering exogenous ligand to the remaining receptors. Studies in rodent models of both learning and memory deficits and deficits in sensory inhibition have confirmed a role for the alpha7 subtype of the nicotinic cholinergic receptor in these processes. Rodent studies also demonstrated the efficacy of a selective partial alpha7 nicotinic agonist, DMXBA, to improve these deficits. Subsequent human clinical trials demonstrated improved sensory inhibition in 12 schizophrenia patients and showed improvement in several subtests of the RBANS learning and memory assessment instrument. These data suggest that therapeutic agents selected for alpha7 nicotinic activity may have utility in treating certain symptoms of schizophrenia.

Pulmonary disease among inpatient decedents: Impact of schizophrenia

OBJECTIVES

Determine the risk associated with schizophrenia for common pulmonary illness (pneumonia and chronic obstructive pulmonary disorder (COPD)) during the last year of life.

METHODS

Inpatient decedents in Veterans (VA) hospitals in 2002 (N=27,798) were identified. Logistic regression modeled diagnosis of pulmonary illness in either the final year or final admission as a function of schizophrenia, smoking history and other covariates.

RESULTS

Among decedents, 943 (3%) had schizophrenia, 3% were women, most were white (76%) or African-American (18%), and average age at death was 72.4 years (SD 11.5). Three-fifths received VA outpatient care in the year prior to death. Among those with schizophrenia, only two-fifths had outpatient care. Pneumonia was more common among schizophrenia patients (38% vs 31%) as was COPD (46% vs 38%). In models controlling for history of smoking and other covariates, schizophrenia was a risk factor for pulmonary disease in the last year of life (OR=1.9, 95% CI 1.6-2.2) but less so for final-stay pulmonary disease (OR=1.5, 95% CI 1.3-1.7).

CONCLUSIONS

VA inpatient decedents with schizophrenia were at increased risk for pneumonia and COPD, independent of smoking indicators. Clinicians treating schizophrenia patients need to be especially alert to potential comorbid medical conditions and ensure vulnerable patients receive appropriate care.

Effects of acute abstinence, reinstatement, and mecamylamine on biochemical and behavioral measures of cigarette smoking in schizophrenia

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.

Schizophrenia and the alpha7 nicotinic acetylcholine receptor

In addition to the devastating symptoms of psychosis, many people with schizophrenia also suffer from cognitive impairment. These cognitive symptoms lead to marked dysfunction and can impact employability, treatment adherence, and social skills. Deficits in P50 auditory gating are associated with attentional impairment and may contribute to cognitive symptoms and perceptual disturbances. This nicotinic cholinergic-mediated inhibitory process represents a potential new target for therapeutic intervention in schizophrenia. This chapter will review evidence implicating the nicotinic cholinergic, and specifically, the alpha7 nicotinic receptor system in the pathology of schizophrenia. Impaired auditory sensory gating has been linked to the alpha7 nicotinic receptor gene on the chromosome 15q14 locus. A majority of persons with schizophrenia are heavy smokers. Although nicotine can acutely reverse diminished auditory sensory gating in people with schizophrenia, this effect is lost on a chronic basis due to receptor desensitization. The alpha7 nicotinic agonist 3-(2,4 dimethoxy)benzylidene-anabaseine (DMXBA) can also enhance auditory sensory gating in animal models. DMXBA is well tolerated in humans and a new study in persons with schizophrenia has found that DMXBA enhances both P50 auditory gating and cognition. alpha7 Nicotinic acetylcholine receptor agonists appear to be viable candidates for the treatment of cognitive disturbances in schizophrenia.

Cholinergic circuits and signaling in the pathophysiology of schizophrenia

Central cholinergic signaling has long been associated with aspects of memory, motivation, and mood, each affected functions in neuropsychiatric disorders such as schizophrenia. In this chapter, we review evidence related to the core hypothesis that dysregulation of central cholinergic signaling contributes to the pathophysiology of schizophrenia. Although central cholinergic circuits are resistant to simplification-particularly when one tries to parse the contributions of various classes of cholinergic receptors to disease related phenomena--the potential role of ACh signaling in Schizophrenia pathophysiology deserves careful consideration for prospective therapeutics. The established role of cholinergic circuits in attentional tuning is considered along with recent work on how the patterning of cholinergic activity may modulate corticostriatal circuits affected in schizophrenia.