The role of antipsychotics in smoking and smoking cessation

Brexpiprazole in patients with schizophrenia with or without substance use disorder: an observational study

Background

Partial dopamine D2 receptor agonists are used for psychotic symptoms in adults with schizophrenia spectrum disorders. Recently, interest surged for partial dopamine D2 receptor agonists in substance use disorders (SUDs). Since it is believed that SUDs decrease the efficacy of pharmacotherapy of underlying psychiatric disorders, we tested the efficacy of the partial D2 agonist brexpiprazole in patients with schizophrenia who were either comorbid with a SUD (SUD group) or not comorbid (non-SUD) to assess treatment response and the effect of brexpiprazole on substance craving in SUD.

Methods

We included patients with DSM-5/DSM-5-TR schizophrenia (using SCID-5-CV) aged 18-66 years with either comorbid SUD or non-SUD to treat with brexpiprazole 4 mg/day for 6 months during February-October 2022. Patients were assessed with the Clinical Global Impressions-Severity (CGI-S) scale, the 24-item Brief Psychiatric Rating Scale (BPRS), and the Positive And Negative Syndrome Scale (PANSS) at baseline, weekly for the first 2 months and monthly for the next four. Furthermore, we assessed substance craving in SUD with a visual analog scale for craving (VAScrav) at the same timepoints.

Results

The total sample was 86 (85 analysable) 18- to 64-year-old (mean 39.32 ± 14.09) patients with schizophrenia [51 men (59.3%) and 35 women (40.7%)], of whom 48 SUD (55.8%) (37 men and 11 women) and 38 non-SUD (44.2%) (14 men and 24 women). No serious or persistent adverse events developed over the study period, but one patient dropped out for subjective akathisia. Results indicated the main effects of time with improvements over the course of the study for CGI-S, BPRS, and PANSS in both SUD and non-SUD groups and the entire sample, and for VAScrav in SUD. Brexpiprazole was associated with similar significant improvements in both groups at the 6 month endpoint compared to baseline.

Conclusion

Treatment with brexpiprazole for 6 months improved psychotic symptoms in patients with schizophrenia, independently from whether they belonged to the SUD or the non-SUD group; hence, SUD comorbidity did not confer treatment resistance to brexpiprazole. Furthermore, in the SUD group, we observed reduced substance craving.

Tobacco smoking related to childhood trauma mediated by cognitive control and impulsiveness in severe mental disorders

BACKGROUND

People with severe mental disorders (SMDs) show an increased prevalence of tobacco smoking compared to the general population. Tobacco smoking and other adult adverse health behaviors have been associated with traumatic experiences in childhood. In the present study we investigated the relationship between childhood trauma and tobacco smoking in people with SMDs, including the possible mediating role of cognitive- and personality characteristics, i.e. cognitive control, impulsiveness, affective lability and self-esteem.

METHODS

Enrolled in the study were 871 participants with schizophrenia (SCZ, N = 484) and bipolar (BD, N = 387) spectrum disorders. We assessed tobacco smoking behavior (yes/no and amount), and history of childhood trauma with the Childhood Trauma Questionnaire. Data on cognitive control, impulsiveness, affective lability, and self-esteem were available in subsamples. We performed linear and logistic regressions, and conducted mediation analyses in PROCESS. All analyses were as standard adjusted for age, sex, and diagnostic group.

RESULTS

Experience of one or more subtypes of childhood trauma was significantly associated with smoking tobacco in SMDs (p = 0.002). There were no significant associations between childhood trauma and amount of tobacco smoking. Cognitive control and impulsiveness were significant mediators between childhood trauma and tobacco smoking.

CONCLUSIONS

These findings indicate the experience of childhood trauma as a predisposing factor for tobacco smoking in SMDs. Cognitive control and impulsiveness were suggested as mediating mechanisms, indicating the importance of considering inhibition related self-regulatory aspects in efforts to improve health behavior in individuals with SMDs and childhood trauma.

Association between cumulative exposure periods of flupentixol or any antipsychotics and risk of lung cancer

BACKGROUND

Preclinical evidence suggests that certain antipsychotic medications may inhibit the development of lung cancer. This study aims to investigate the association between incident lung cancer and different cumulative exposure periods of flupentixol or any antipsychotics.

METHODS

Using electronic health records from the Hospital Authority in Hong Kong, this nested case-control study included case participants aged 18 years or older with newly diagnosed lung cancer after initiating antipsychotics between January 1, 2003, and August 31, 2022. Each case was matched to up to ten controls of the same sex and age, who were also antipsychotic users. Multivariable conditional logistic regression models were conducted to quantify the association between lung cancer and different cumulative exposure times of flupentixol (0-365 days [ref]; 366-1825 days; 1826+ days) and any antipsychotics (1-365 days [ref]; 366-1825 days; 1826+ days), separately.

RESULTS

Here we show that among 6435 cases and 64,348 matched controls, 64.06% are males, and 52.98% are aged 65-84 years. Compared to patients with less than 365 days of exposure, those with 366-1825 days of exposure to flupentixol (OR = 0.65 [95% CI, 0.47-0.91]) and any antipsychotics (0.42 [0.38-0.45]) have a lower risk of lung cancer. A decreased risk is observed in patients who have 1826+ days of cumulative use of any antipsychotics (0.54 [0.47-0.60]).

CONCLUSIONS

A reduced risk of lung cancer is observed in patients with more than one year of exposure to flupentixol or any antipsychotics. Further research on the association between lung cancer and other antipsychotic agents is warranted.

Age-specific impacts of nicotine and withdrawal on hippocampal neuregulin signalling

Smoking remains the leading cause of preventable death in the United States, with 87% of smokers starting before the age of 18. Age of initiation is a major predictive factor for smoking frequency and successful smoking cessation. People who initiate smoking during adolescences are 2.33 times more likely to become heavy smokers and half as likely to quit compared with smokers who started during adulthood. Additionally, schizophrenia, a disease state linked to altered neurodevelopment during adolescence, is a major predictive factor for smoking status. Smoking rates among people suffering from schizophrenia are between 60% and 90%. Interestingly, the Neuregulin Signalling Pathway (NSP), which plays an important role in neurodevelopment, is implicated in both schizophrenia and nicotine use disorder. Specifically, SNPS in neuregulin 3 (Nrg3) and Erb-B2 Receptor Tyrosine Kinase 4 (ErbB4) have been associated with smoking cessation outcomes and schizophrenia. Here, we examine the effects of chronic nicotine (18 mg/kg/day) and 24-h withdrawal on NSP gene expression in the hippocampus of adult (20-week-old) and adolescent (4-week-old) mice. We show that withdrawal from chronic nicotine decreased the expression of Erbb4 mRNA in the hippocampus of the adult mice but increased the expression of cytosolic Erbb4 protein in adolescent mice. Nrg3 mRNA and protein expression was not altered by chronic nicotine or withdrawal in the adult or adolescent cohorts, but Nrg3 mRNA and synaptosomal protein expression was lower in the adult withdrawal group when compared with their adolescent counterparts. These results highlight the age-specific effects of nicotine withdrawal on the NSP and may contribute to the lower quit rate and higher cigarette consumption of smokers who initiation during adolescences.

Non-pharmacological interventions for smoking in persons with schizophrenia spectrum disorders - A systematic review

INTRODUCTION

The rates and intensity of tobacco use are higher in persons with schizophrenia spectrum disorders (PwS) compared to the general population, contributing to increased morbidity and mortality. We aimed to systematically review randomised control trials (RCTs) that used non-pharmacological interventions to reduce or cease tobacco use in PwS.

METHODS

We searched PubMed, EBSCO, ProQuest and PsycINFO for RCTs, published between January 2004 and December 2019, which included adult PwS. Studies providing self-reported or biochemically measured reduction of tobacco use and cessation after a minimum follow-up period of 6 months were included. We used the Cochrane Risk of Bias (ROB) tool for assessing the quality of selected studies.

RESULTS

Of the six included trials, two compared non-pharmacological interventions alone while four compared combinations with pharmacological interventions with routine care. The non-pharmacological interventions varied widely. Continuous abstinence and seven days point-prevalence abstinence (7 PPA) were reported in 2 and 4 studies respectively, with one study assessing both. All six trials measured reduction in the number of cigarettes smoked, but only two trials reported significant reductions in intervention groups. No worsening of psychiatric symptoms was reported.

CONCLUSIONS

Two trials were rated as "low risk", and 4 trials as "some concerns" on the ROB tool. Heterogeneity among trials precluded meta-analysis. Abstinence was significantly higher among groups who were given combination interventions, and intervention groups in studies showed significantly greater or a trend towards reduction in the number of cigarettes smoked than controls. No specific method of non-pharmacological management was conclusively favoured.

IMPLICATIONS

Reduction in cigarettes smoked seemed to significantly favour or show non-significant trends favouring intervention groups over controls, while abstinence was significantly higher among groups in studies that used specific combination interventions. Combinations of pharmacological and non-pharmacological treatment were better than non-pharmacological interventions used in isolation, for facilitating abstinence and reduction in cigarettes smoked. Specific interventions such as home visits and contingent reinforcement merit further study. Trials included in this study were conducted in high-income and upper-middle-income countries. Thus, the application of these interventions to low and middle-income countries (LAMICs) needs to be further studied.

Feasibility of a Consumer Centred Tobacco Management intervention in Community Mental Health Services in Australia

This study tested a new program for helping smokers with severe mental illness to reduce their tobacco use, together with determining the feasibility of such research in community mental health settings in Australia. Five Neami National sites trialled a Consumer Centred Tobacco Management program called Kick the Habit (n = 34). The intervention included two weeks of free Nicotine Replacement Therapy (patches only) but participants also used a variety of self-funded delivery types in addition or as an alternative to the subsidised nicotine patch. At the 3-month follow-up, Kick the Habit participants had reduced their number of daily cigarettes, dependency levels and average weekly expenditure on tobacco. Although a larger study is required, Kick the Habit represents a promising intervention for tobacco management in community mental health services. The challenges and lessons learnt for scaling up to a larger trial and integration into business-as-usual practice across multiple sites are discussed.

Cigarette smoking in subjects maintained with methadone or buprenorphine: The role of psychiatric symptoms and psychological distress

OBJECTIVE

The relationship between cigarette smoking, psychiatric symptoms/psychological distress in subjects maintained with methadone or buprenorphine was studied.

METHODS

1049 subjects with a diagnosis of heroin use disorder were enrolled. The Symptom Checklist-90-Revised (SCL-90-R) and the General Health Questionnaire-12 (GHQ-12) were administered. The analyses were run in the whole sample and stratified for substitution therapies.

RESULTS

In the whole sample as well as among subjects maintained with methadone, the number of cigarettes smoked daily was associated with SCL-90-R Global score (whole sample: p = 0.001; ΔR² = 0.012; subjects maintained with methadone: p ≤ 0.001; ΔR² = 0.019) and with GHQ-12 (whole sample: p = 0.001; ΔR² = 0.013; subjects maintained with methadone: p = 0.01; ΔR² = 0.010) while among subjects maintained with buprenorphine, the number of cigarettes smoked daily was associated with SCL-90-R Global score (p = 0.05; ΔR² = 0.020).

CONCLUSION

Psychiatric symptoms were associated with the number of cigarettes smoked daily among subjects maintained with methadone and among those maintained with buprenorphine, thus deserving clinical attention.

Tobacco smoking is associated with antipsychotic medication, physical aggressiveness, and alcohol use disorder in schizophrenia: results from the FACE-SZ national cohort

Tobacco smoking is common in schizophrenia and is one of the main causes of premature mortality in this disorder. Little is known about clinical correlates and treatments associated with tobacco smoking in patients with schizophrenia. Still, a better characterization of these patients is necessary, in a personalized care approach. Aggressiveness and childhood trauma have been associated with tobacco smoking in general population, but this association has never been explored in schizophrenia. Our study examines the clinical and therapeutic characteristics of tobacco smoking in schizophrenia. 474 stabilized patients (mean age = 32.2; 75.7% male gender; smokers n = 207, 54.6%) were consecutively included in the network of the FondaMental Expert centers for Schizophrenia and assessed with valid scales. Current tobacco status was self-declared. Aggressiveness was self-reported with Buss-Perry Aggressiveness Questionnaire and Childhood Trauma with Childhood Trauma Questionnaire. Ongoing treatment was reported. In univariate analysis, tobacco smoking was associated with lower education level (p < 0.01), positive syndrome (p < 0.01), higher physical aggressiveness (p < 0.001), alcohol dependence (p < 0.001), and First Generation Antipsychotics (FGAs) use (p = 0.018). In a multivariate model, tobacco smoking remained associated with physical aggressiveness (p < 0.05), current alcohol dependence (p < 0.01) and FGA use (p < 0.05). No association was observed with childhood trauma history, mood disorder, suicidal behavior, psychotic symptom, global functioning or medication adherence. Patients with tobacco use present clinical and therapeutic specificities, questioning the neurobiological links between tobacco and schizophrenia. They could represent a specific phenotype, with specific clinical and therapeutic specificities that may involve interactions between cholinergic-nicotinic system and dopaminergic system. Further longitudinal studies are needed to confirm the potential efficacy of second generation antipsychotics (SGAs) on tobacco use in schizophrenia and to develop effective strategies for tobacco cessation in this population.

Ideal cardiovascular health and its association with sedentary behaviour and fitness in psychiatric patients. The PsychiActive project

BACKGROUND AND AIMS

Ideal cardiovascular health (CVH) was defined as meeting ideal levels of 4 health behaviours (smoking, body mass index, physical activity, and diet) and 3 biological factors (blood pressure, total cholesterol, and glucose) and is inversely related to cardiovascular disease and mortality. However, the prevalence of ideal CVH in patients with severe mental illness and the possible independent associations of sedentary behaviour and fitness with CVH score are unexplored.

METHODS AND RESULTS

This study included 142 (34 women) outpatients with severe mental illness (primarily schizophrenia, n = 92). CVH was evaluated according to the American Heart Association guidelines. Sedentary behaviour, cardiorespiratory fitness, and muscular strength were measured by an activity-monitor, the 6-min walk test, and handgrip dynamometry. Cardiorespiratory fitness and strength values were combined in a composite fitness score. The prevalence of ideal CVH was: non-smoking (47.9%), body mass index (16.9), physical activity (83.1%), diet (10.4%), blood pressure (40.4%), total cholesterol (62.9%), and plasma glucose (66.7%). Low levels of sedentary behaviour and high cardiorespiratory, strength, and composite fitness score were associated with meeting the ideal threshold in most CVH metrics and having higher global CVH score; however, only cardiorespiratory and composite fitness score remained significantly related to global CVH score independent of sedentary behaviour and multiple confounders.

CONCLUSIONS

Patients with severe mental illness generally have low prevalence of ideal CVH metrics, especially diet and body mass index. Additionally, our findings suggest the need or considering cardiorespiratory fitness, regardless of sedentary behaviour, to promote ideal CVH in this population.

Schizophrenia and Nicotine Dependence: What Psychopharmacological Treatment Options are Available for the Duo Perturbationes?

Nicotine dependence has progressively become a foremost community health interest in both the developed and developing nations due to the economic burden and health-related problems. Smoking was significantly higher among patients with schizophrenia in comparison to the general population. Nicotine dependence is not only associated with public stress, but among patients with schizophrenia, smoking brings major challenges to the management. Nicotine may diminish the therapeutic efficacy of the bioavailability of the psychopharmacological agents in-vivo. These duo perturbations, i.e. two clinical conditions co-existed may prevent psychotic symptoms remission among patients suffering from schizophrenia who smoke at the same time. The aim of this review was to highlight the role of pharmacological treatment options and strategies for patients with nicotine dependence in schizophrenia with emphasis on the underlying neurobiological process. The role of nicotine replacement therapy, i.e. norepinephrine-dopamine reuptake inhibition (NDRI) e.g. bupropion and selective partial agonist of α4β2 and full α7-nicotinic acetylcholine receptor e.g. varenicline was deliberated. An ideal choice of drug targets for patients with schizophrenia with nicotine dependence is pivotal to foster a better therapeutic alliance.

Nicotine dependence is associated with depression and childhood trauma in smokers with schizophrenia: results from the FACE-SZ dataset

In a perspective of personalized care for smoking cessation, a better clinical characterization of smokers with schizophrenia (SZ) is needed. The objective of this study was to determine the clinical characteristics of SZ smokers with severe nicotine (NIC) dependence. 240 stabilized community-dwelling SZ smokers (mean age = 31.9 years, 80.4% male gender) were consecutively included in the network of the FondaMental Expert Centers for Schizophrenia and assessed with validated scales. Severe NIC dependence was defined by a Fagerstrom questionnaire score ≥ 7. Depression was defined by a Calgary score ≥ 6. Childhood trauma was self-reported by the Childhood Trauma Questionnaire score (CTQ). Ongoing psychotropic treatment was recorded. Severe NIC dependence was identified in 83 subjects (34.6%), depression in 60 (26.3%). 44 (22.3%) subjects were treated by antidepressants. In a multivariate model, severe NIC dependence remained associated with depression (OR = 3.2, p = 0.006), male gender (OR = 4.5, p = 0.009) and more slightly with childhood trauma (OR = 1.03, p = 0.044), independently of socio-demographic characteristics, psychotic symptoms severity, psychotropic treatments and alcohol disorder. NIC dependence was independently and strongly associated with, respectively, depression and male gender in schizophrenia, and only slightly with history of childhood trauma. Based on these results, the care of both nicotine dependence and depression should be evaluated for an effective smoking cessation intervention in schizophrenia.

Role of the Neuregulin Signaling Pathway in Nicotine Dependence and Co-morbid Disorders

Smoking is currently the leading cause of preventable death in the United States and is responsible for over four million deaths annually worldwide. Therefore, there is a vast clinical unmet need with regards to therapeutics targeting smoking cessation. This is even more apparent when examining smokers co-morbid with psychiatric illness, as rates of smoking in this population are ~4× higher than in the general population. Examining common genetic and molecular signaling pathways impinging upon both smoking behavior and psychiatric illness will lead to a better understanding of co-morbid disorders and potential development of novel therapeutics. Studies have implicated the Neuregulin Signaling Pathway in the pathophysiology of a number of psychiatric illnesses. Additionally, recent studies have also shown an association between the Neuregulin Signaling Pathway and smoking behaviors. This review outlines basic mechanisms of the Neuregulin Signaling Pathway and how it may be exploited for precision medicine approaches in treating nicotine dependence and mental illness.

The effect of nicotine dependence on psychopathology in patients with schizophrenia

Introduction. Our study aims to determine the prevalence of nicotine dependence and investigate the effect of nicotine dependence on psychopathology among schizophrenia patients. Methods. A cross-sectional study was carried out in an outpatient psychiatric clinic at a general hospital in Malaysia. 180 recruited subjects were administered the Malay version of Mini International Neuropsychiatric Interview (MINI), the Positive and Negative Symptom Scale (PANSS), and the Malay version of Fagerstrom Test for Nicotine Dependence (FTND-M) questionnaires. Results. The prevalence of nicotine dependence among the subjects was 38.1% (n = 69) and they were mainly composed of male gender, Malay ethnicity, being treated with atypical antipsychotics, and taking other illicit drugs or alcohol. Subjects with severe nicotine dependence scored less in the negative subscale of PANSS compared with the nonsmokers (P = 0.011). On performing the hierarchy multiple regressions, dependence status still significantly predicted negative scores after adjusting the confounders (t = −2.87, P = 0.005). Conclusion. The rate of nicotine use disorder among schizophrenia patients in this study is higher than that of the general population in Malaysia. The significant association between nicotine dependence and negative psychopathology symptoms will help the healthcare practitioners in their management of nicotine dependence among schizophrenia patients.

Smoking in schizophrenic patients: A critique of the self-medication hypothesis

A common remark among laypeople, and notably also among mental health workers, is that individuals with mental illnesses use drugs as self-medication to allay clinical symptoms and the side effects of drug treatments. Roots of the self-medication concept in psychiatry date back at least to the 1980s. Observations that rates of smokers in schizophrenic patients are multiple times the rates for regular smoking in the general population, as well as those with other disorders, proved particularly tempting for a self-medication explanation. Additional evidence came from experiments with animal models exposed to nicotine and the identification of neurobiological mechanisms suggesting self-medication with smoking is a plausible idea. More recently, results from studies comparing smoking and non-smoking schizophrenic patients have led to the questioning of the self-medication hypothesis. Closer examination of the literature points to the possibility that smoking is less beneficial on schizophrenic symptomology than generally assumed while clearly increasing the risk of cancer and other smoking-related diseases responsible for early mortality. It is a good time to examine the evidence for the self-medication concept as it relates to smoking. Our approach is to focus on data addressing direct or implied predictions of the hypothesis in schizophrenic smokers.

Health care professionals implementing a smoke-free policy at inpatient psychiatric units

Smoke-free grounds policies (SFGPs) were introduced to inpatient psychiatric hospital settings to improve health among patients, staff, and visitors. We conducted an ethnographic study in Northern British Columbia, Canada, to describe how the implementation of SFGPs is affected by institutional cultures. Data reported here included participant observation, document review, informal discussions (n = 11), and interviews with health care professionals (HCPs; n = 19) and staff (n = 2) at two hospitals. We used iterative and inductive processes to derive thematic findings. Findings related to HCPs illustrate how local contexts and cultural factors affect SFGP implementation. These factors included individual beliefs and attitudes, the influence of group norms, leadership and consensus building, and locale-specific norms. Strong, consultative leadership, in which leaders solicited input from and long-term support of people most directly responsible for policy implementation, was key to success.

Examination of the role of dopamine D₂ and adrenergic α₂ receptors in resurgence of food seeking

Resurgence refers to the reappearance of an extinguished operant behavior when reinforcement for an alternative behavior is also subsequently discontinued. Resurgence has been noted as a source of relapse to problem behavior following interventions involving alternative reinforcement, and has also been recently used as an animal model of relapse to drug seeking induced by reinforcement loss. Existing information about the neuropharmacology of resurgence is scarce, but suggests overlap between relapse observed in the resurgence model and relapse observed in reinstatement and renewal models. In the present experiment rats earned food pellets for pressing a target lever in Phase I. In Phase II lever pressing no longer produced food, but food was delivered for an alterative nose poke response. Finally in Phase III, neither response produced food deliveries. Prior to these Phase III sessions, separate groups of rats were injected with 0, 50, or 100 μg/kg of the dopamine D2 receptor antagonist raclopride or 0, 20, or 40 μg/kg of α 2 agonist clonidine. Both doses of raclopride were effective in blocking resurgence, but there was evidence that the higher dose did so via motor rather than motivational impairment. Only the higher dose of clonidine blocked resurgence, but did so with no evidence of motor impairment. Raclopride significantly impacted extinction of the alternative poke at both doses tested, whereas clonidine had no effect at either dose. The results of the present study provide additional information about the neuropharmacology of resurgence, as well as additional evidence of overlap between resurgence, reinstatement, and renewal.

Inverse association between 18-carbon trans fatty acids and intelligence quotients in smoking schizophrenia patients

This study aimed to investigate polyunsaturated (PUFA) and trans isomeric fatty acid status in schizophrenia patients. Fatty acid composition of plasma phospholipids (PL) and triacylglycerols (TG) was analyzed by gas chromatography in 29 schizophrenia patients and 15 healthy controls. We found no difference in PL n-3 fatty acid status between the two groups, while the values of 22:5n-6 were significantly higher in patients with schizophrenia than in controls. In TG, values of docosatrienoic acid (20:3n-3) and docosapentaenoic acid (20:5n-3) were significantly higher in schizophrenia patients than in controls. We found no difference in the trans fatty acid status between patients and controls. In smoking schizophrenia patients significant negative correlations were detected between Wechsler adult full-scale intelligence quotients and values of total trans fatty acids in PL lipids, whereas no such correlation was seen either in non-smoking schizophrenia patients, or in healthy controls. While data obtained in the present study fail to furnish evidence for n-3 PUFA supplementation to the diet of patients with schizophrenia, they indicate that in smoking schizophrenia patients high dietary exposure to trans fatty acids is associated with lower intelligence quotients.

Effects of intravenous nicotine on prepulse inhibition in smokers and non-smokers: relationship with familial smoking

RATIONALE

The reinforcing properties of nicotine may be, in part, derived from its ability to enhance certain forms of cognitive processing. Several animal and human studies have shown that nicotine increases prepulse inhibition (PPI) of the startle reflex. However, it remains unclear whether these effects are related to smoking susceptibility.

OBJECTIVES

The current study examined the effects of intravenously delivered nicotine on PPI in smokers and non-smokers, as well as its association with a quantitative index of familial smoking.

METHODS

The sample consisted of 30 non-smokers and 16 smokers, who completed an initial assessment, followed on a separate day by a laboratory assessment of PPI prior to and following each of two intravenous nicotine infusions. Separate doses were used in smoker and non-smoker samples.

RESULTS

Analyses indicated that both nicotine infusions acutely enhanced PPI among non-smokers, and this enhancement was positively related to the degree of smoking among first and second-degree relatives. Smokers also displayed PPI enhancement after receiving the first infusion, but this effect was unrelated to familial smoking.

CONCLUSIONS

These data suggest that the PPI paradigm may have utility as an endophenotype for cognitive processes which contribute to smoking risk.

Do atypical antipsychotics really enhance smoking reduction more than typical ones?: the effects of antipsychotics on smoking reduction in patients with schizophrenia

Whether atypical antipsychotics (AAs) can enhance smoking reduction in schizophrenic patients remains controversial because of methodological limitations in existing studies. This study explored whether certain types of antipsychotics predict smoking reduction in schizophrenic patients. Three hundred eight smoking, predominantly male schizophrenic patients (271/308 [88.9%]) participated in an 8-week open-label study with antismoking medications (high-dose, low-dose nicotine transdermal patch and bupropion). Antipsychotics were classified into (1) typical antipsychotics (TAs) and (2) AAs, including multiacting receptor-targeted antipsychotics (clozapine, olanzapine, and quetiapine), serotonin-dopamine antagonists (risperidone), D2/D3 receptor antagonists (amisulpride), and partial dopamine receptor agonists (aripiprazole). A general linear model was used to explore whether types of antipsychotic predict changes in the number of cigarettes smoked per day (CPD) and the score of the Fagerstrom Test for Nicotine Dependence (FTND) while controlling for confounding factors. The type of antipsychotic (TAs or AAs) was not significantly associated with smoking cessation (n = 21; χ = 1.8; df = 4; P = 0.77). Regarding smoking reduction, the type of antipsychotic was significantly predictive of a change in the CPD (P = 0.027; partial eta square = 0.055) and FTND scores (P = 0.002; partial eta square = 0.073). The 95% confidence intervals of the estimated means of change in the CPD and FTND scores did not contain zero only among subjects on TAs or clozapine.These findings suggest that TAs and clozapine enhance smoking reduction compared with nonclozapine atypical antipsychotics in schizophrenic patients. The mechanisms underlying the effects of various antipsychotics on smoking reduction remain unclear and warrant future study.

The dynamics of DNA methylation in schizophrenia and related psychiatric disorders

Major psychiatric disorders such as schizophrenia (SZ) and bipolar disorder (BP) with psychosis (BP+) express a complex symptomatology characterized by positive symptoms, negative symptoms, and cognitive impairment. Postmortem studies of human SZ and BP+ brains show considerable alterations in the transcriptome of a variety of cortical structures, including multiple mRNAs that are downregulated in both inhibitory GABAergic and excitatory pyramidal neurons compared with non-psychiatric subjects (NPS). Several reports show increased expression of DNA methyltransferases in telencephalic GABAergic neurons. Accumulating evidence suggests a critical role for altered DNA methylation processes in the pathogenesis of SZ and related psychiatric disorders. The establishment and maintenance of CpG site methylation is essential during central nervous system differentiation and this methylation has been implicated in synaptic plasticity, learning, and memory. Atypical hypermethylation of candidate gene promoters expressed in GABAergic neurons is associated with transcriptional downregulation of the corresponding mRNAs, including glutamic acid decarboxylase 67 (GAD67) and reelin (RELN). Recent reports indicate that the methylation status of promoter proximal CpG dinucleotides is in a dynamic balance between DNA methylation and DNA hydroxymethylation. Hydroxymethylation and subsequent DNA demethylation is more complex and involves additional proteins downstream of 5-hydroxymethylcytosine, including members of the base excision repair (BER) pathway. Recent advances in our understanding of altered CpG methylation, hydroxymethylation, and active DNA demethylation provide a framework for the identification of new targets, which may be exploited for the pharmacological intervention of the psychosis associated with SZ and possibly BP+.

Cotinine: Beyond that Expected, More than a Biomarker of Tobacco Consumption

A greater incidence of tobacco consumption occurs among individuals with psychiatric conditions including post-traumatic stress disorder (PTSD), bipolar disorder, major depression, and schizophrenia, compared with the general population. Even when still controversial, it has been postulated that smoking is a form of self-medication that reduces psychiatric symptoms among individuals with these disorders. To better understand the component(s) of tobacco-inducing smoking behavior, greater attention has been directed toward nicotine. However, in recent years, new evidence has shown that cotinine, the main metabolite of nicotine, exhibits beneficial effects over psychiatric symptoms and may therefore promote smoking within this population. Some of the behavioral effects of cotinine compared to nicotine are discussed here. Cotinine, which accumulates in the body as a result of tobacco exposure, crosses the blood-brain barrier and has different pharmacological properties compared with nicotine. Cotinine has a longer plasma half-life than nicotine and showed no addictive or cardiovascular effects in humans. In addition, at the preclinical level, cotinine facilitated the extinction of fear memory and anxiety after fear conditioning, improved working memory in a mouse model of Alzheimer’s disease (AD) and in a monkey model of schizophrenia. Altogether, the new evidence suggests that the pharmacological and behavioral effects of cotinine may play a key role in promoting tobacco smoking in individuals that suffer from psychiatric conditions and represents a new potential therapeutic agent against psychiatric conditions such as AD and PTSD.

Nicotine dependence and illness severity in schizophrenia

BACKGROUND

Reasons for the increased prevalence of cigarette smoking in schizophrenia are unclear. Studies assessing clinical symptoms have sampled heterogeneous populations, with discrepant findings.

AIMS

To examine the relationship between clinical features, social adjustment and nicotine dependence in a geographically defined population of people with schizophrenia.

METHOD

Cross-sectional clinical study of 131 people with schizophrenia in Nithsdale, Scotland.

RESULTS

Smokers were younger, mostly males and three times more likely to be unemployed. Those with severe nicotine dependence had greater scores on the positive subscale of the Positive and Negative Syndrome Scale (PANSS), and were prescribed higher doses of antipsychotic. Those with mild-moderate dependence had greater scores on the PANSS negative subscale. Greater symptom severity was associated with poorer social adjustment. Psychopathology and social adjustment were similar in quitters and never-smokers.

CONCLUSIONS

Our findings indicate an association between nicotine dependence, clinical symptoms and social adjustment in schizophrenia. Although causal links cannot be inferred, identifying the relationship between nicotine dependence and psychopathology may have some value in the management of smoking in schizophrenia. Further longitudinal studies are required to explore this relationship.

Different impacts of aquaporin 4 and MAOA allele variation among olanzapine, risperidone, and paliperidone in schizophrenia

Apoptosis has been considered to be involved in schizophrenia. Water channels are modulated just before apoptosis. In the aquaporin family, aquaporin 4 (AQP-4) is most highly expressed in the brain and is supposed to play an important role in a neuronal environment. In this clinical study, we investigated the relationship between the AQP-4 polymorphism and drug response in schizophrenia under the control of the MAOA (monoamine oxidase A) promoter gene. We recruited 91 patients with schizophrenia, and they were randomized to receive olanzapine (n = 44), risperidone (n = 23), or paliperidone (n = 24). Genotyping of AQP-4 and MAOA polymorphisms was done in all patients. Patients with the AQP-4 non-C polymorphism needed a higher dosage of olanzapine for treatment (z = 4.163, P = 0.041), and patients with a short form of the MAOA polymorphism needed a higher dosage of risperidone for treatment (z = 5.124, P = 0.024). Patients who smoked cigarettes needed a higher dosage of olanzapine for treatment (z = 4.905, P = 0.027), but cigarette smoking did not affect the dosage of paliperidone. The AQP-4 polymorphism may have an effect in influencing the dosage of olanzapine. However, the roles of AQP-4 polymorphisms in the blood-brain barrier and different neuroprotective effects need further exploration in future studies.

All-cause mortality and medication risk factors in schizophrenia: a prospective cohort study

BACKGROUND

It is well established that persons with schizophrenia have high mortality rates. There is conflicting evidence that antipsychotic and perhaps other medications routinely used to treat schizophrenia contribute to mortality risk.

METHODS

A health insurer database was used to examine schizophrenia diagnosis and mortality in 2008. Information from the period 2006-2008 was used to analyze demographics and medication prescriptions. The risk set composed of patients with schizophrenia using an antipsychotic (n = 7415) and a group of randomly chosen control subjects (n = 97,726).

RESULTS

The mortality risk for having a diagnosis of schizophrenia and using an antipsychotic versus the random control group was a hazard ratio (HR) of 2.6; 95% CI, 2.0-3.2. Over the 3-year period, age, receiving a first-generation antipsychotic, and the use of a mood stabilizer were associated with a higher risk of mortality: HR, 1.06; 95% CI, 1.04-1.08; HR, 2.36; 95% CI, 1.38-4.04; and HR, 8.42; 95% CI, 3.06-24.07, respectively.

CONCLUSION

Patients with schizophrenia have higher mortality rates than normal controls. The type of antipsychotic and concomitant medication can affect mortality rates in schizophrenia.