The effects of transdermal nicotine on cognition in nonsmokers with schizophrenia and nonpsychiatric controls

A systematic review of digital interventions for smoking cessation in patients with serious mental illness

Tobacco smoking is highly prevalent among patients with serious mental illness (SMI), with known deleterious consequences. Smoking cessation is therefore a prioritary public health challenge in SMI. In recent years, several smoking cessation digital interventions have been developed for non-clinical populations. However, their impact in patients with SMI remains uncertain. We conducted a systematic review to describe and evaluate effectiveness, acceptability, adherence, usability and safety of digital interventions for smoking cessation in patients with SMI. PubMed/MEDLINE, EMBASE, CINAHL, Web of Science, PsychINFO and the Cochrane Tobacco Addiction Group Specialized Register were searched. Studies matching inclusion criteria were included and their information systematically extracted by independent investigators. Thirteen articles were included, which reported data on nine different digital interventions. Intervention theoretical approaches ranged from mobile contingency management to mindfulness. Outcome measures varied widely between studies. The highest abstinence rates were found for mSMART MIND (7-day point-prevalent abstinence: 16-40%). Let's Talk About Quitting Smoking reported greater acceptability ratings, although this was not evaluated with standardized measures. Regarding usability, Learn to Quit showed the highest System Usability Scale scores [mean (s.d.) 85.2 (15.5)]. Adverse events were rare and not systematically reported. Overall, the quality of the studies was fair to good. Digitally delivered health interventions for smoking cessation show promise for improving outcomes for patients with SMI, but lack of availability remains a concern. Larger trials with harmonized assessment measures are needed to generate more definitive evidence and specific recommendations.

Smoking and attention in schizophrenia spectrum disorders: What are we neglecting?

Introduction

Individuals with schizophrenia spectrum disorders (SSDs) record elevated rates of smoking, which is often attributed to their effort to self-medicate cognitive and attentional symptoms of their illness. Empirical evidence for this hypothesis is conflicting, however. In this study, we aimed to test predictions derived from the cognitive self-medication hypothesis. We predicted that cigarette smoking status and extent would predict the attentional performance of participants with SSDs. Simultaneously, we wished to address methodological gaps in previous research. We measured distinct attentional components and made adjustments for the effects of other, attention-modulation variables.

Methods

Sixty-one smokers (82.0% males, 26.73 ± 6.05 years) and 61 non-smokers (50.8% males, 27.10 ± 7.90 years) with recent-onset SSDs completed an X-type Continuous Performance Test, which was used to derive impulsivity and inattention component scores. Relationships between the two component scores and cigarette smoking status and extent were assessed using hierarchical regression. Effects of estimated premorbid intellectual functioning and antipsychotic medication dosage were held constant.

Results

Smokers had significantly higher inattention component scores than non-smokers when covariates were controlled (p = 0.026). Impulsivity remained unaffected by smoking status (p = 0.971). Cigarette smoking extent, i.e., the number of cigarettes smoked per day, was not associated with either inattention (p = 0.414) or impulsivity (p = 0.079).

Conclusion

Models of smoking-related attentional changes can benefit from the inclusion of sample-specific component scores and attention-modulating covariates. Under these conditions, smokers with SSDs can show a partial attentional benefit. However, the limited scope of this benefit suggests that the cognitive self-medication hypothesis requires further testing or reconsidering.

The role of the SLC6A3 3' UTR VNTR in nicotine effects on cognitive, affective, and motor function

RATIONALE

Nicotine has been widely studied for its pro-dopaminergic effects. However, at the behavioural level, past investigations have yielded heterogeneous results concerning effects on cognitive, affective, and motor outcomes, possibly linked to individual differences at the level of genetics. A candidate polymorphism is the 40-base-pair variable number of tandem repeats polymorphism (rs28363170) in the SLC6A3 gene coding for the dopamine transporter (DAT). The polymorphism has been associated with striatal DAT availability (9R-carriers > 10R-homozygotes), and 9R-carriers have been shown to react more strongly to dopamine agonistic pharmacological challenges than 10R-homozygotes.

OBJECTIVES

In this preregistered study, we hypothesized that 9R-carriers would be more responsive to nicotine due to genotype-related differences in DAT availability and resulting dopamine activity.

METHODS

N=194 non-smokers were grouped according to their genotype (9R-carriers, 10R-homozygotes) and received either 2-mg nicotine or placebo gum in a between-subject design. Spontaneous blink rate (SBR) was obtained as an indirect measure of striatal dopamine activity and smooth pursuit, stop signal, simple choice and affective processing tasks were carried out in randomized order.

RESULTS

Reaction times were decreased under nicotine compared to placebo in the simple choice and stop signal tasks, but nicotine and genotype had no effects on any of the other task outcomes. Conditional process analyses testing the mediating effect of SBR on performance and how this is affected by genotype yielded no significant results.

CONCLUSIONS

Overall, we could not confirm our main hypothesis. Individual differences in nicotine response could not be explained by rs28363170 genotype.

Noninvasive Brain Stimulation for Nicotine Dependence in Schizophrenia: A Mini Review

Individuals with schizophrenia are 10 times more likely to have a tobacco use disorder than the general population. Up to 80% of those with schizophrenia smoke tobacco regularly, a prevalence three-times that of the general population. Despite the striking prevalence of tobacco use in schizophrenia, current treatments are not tailored to the pathophysiology of this population. There is growing support for use of noninvasive brain stimulation (NIBS) to treat substance use disorders (SUDs), particularly for tobacco use in neurotypical smokers. NIBS interventions targeting the dorsolateral prefrontal cortex have been effective for nicotine dependence in control populations-so much so that transcranial magnetic stimulation is now FDA-approved for smoking cessation. However, this has not borne out in the studies using this approach in schizophrenia. We performed a literature search to identify articles using NIBS for the treatment of nicotine dependence in people with schizophrenia, which identified six studies. These studies yielded mixed results. Is it possible that nicotine has a unique effect in schizophrenia that is different than its effect in neurotypical smokers? Individuals with schizophrenia may receive additional benefit from nicotine's pro-cognitive effects than control populations and may use nicotine to improve brain network abnormalities from their illness. Therefore, clinical trials of NIBS interventions should test a schizophrenia-specific target for smoking cessation. We propose a generalized approach whereby schizophrenia-specific brain circuitry related to SUDs is be identified and then targeted with NIBS interventions.

Evidence for Schizophrenia-Specific Pathophysiology of Nicotine Dependence

Tobacco use is the top preventable cause of early mortality in schizophrenia. Over 60% of people with schizophrenia smoke, three times the general prevalence. The biological basis of this increased risk is not understood, and existing interventions do not target schizophrenia-specific pathology. We therefore used a connectome-wide analysis to identify schizophrenia-specific circuits of nicotine addiction. We reanalyzed data from two studies: In Cohort 1, 35 smokers (18 schizophrenia, 17 control) underwent resting-state fMRI and clinical characterization. A multivariate pattern analysis of whole-connectome data was used to identify the strongest links between cigarette use and functional connectivity. In Cohort 2, 12 schizophrenia participants and 12 controls were enrolled in a randomized, controlled crossover study of nicotine patch with resting-state fMRI. We correlated change in network functional connectivity with nicotine dose. In Cohort 1, the strongest (p < 0.001) correlate between connectivity and cigarette use was driven by individual variation in default mode network (DMN) topography. In individuals with greater daily cigarette consumption, we observed a pathological expansion of the DMN territory into the identified parieto-occipital region, while in individuals with lower daily cigarette consumption, this region was external to the DMN. This effect was entirely driven by schizophrenia participants. Given the relationship between DMN topography and nicotine use we observed in Cohort 1, we sought to directly test the impact of nicotine on this network using an independent second cohort. In Cohort 2, nicotine reduced DMN connectivity in a dose-dependent manner (R = -0.50; 95% CI -0.75 to -0.12, p < 0.05). In the placebo condition, schizophrenia subjects had hyperconnectivity compared to controls (p < 0.05). Nicotine administration normalized DMN hyperconnectivity in schizophrenia. We here provide direct evidence that the biological basis of nicotine dependence is different in schizophrenia and in non-schizophrenia populations. Our results suggest the high prevalence of nicotine use in schizophrenia may be an attempt to correct a network deficit known to interfere with cognition.

Nicotine Administration Normalizes Behavioral and Neurophysiological Perturbations in the MAM Rodent Model of Schizophrenia

BACKGROUND

The present study utilized the methylazoxymethanol (MAM) neurodevelopmental rodent model of schizophrenia (SCZ) to evaluate the hypothesis that individuals with SCZ smoke in an attempt to "self-medicate" their symptoms through nicotine (NIC) intake.

METHODS

To explore this question, we examined the effects of acute and chronic administration of NIC in 2 established behavioral tests known to be disrupted in the MAM model: prepulse inhibition of startle and novel object recognition. Additionally, we assessed the effects of acute and chronic NIC on 2 indices of the pathophysiology of SCZ modeled by MAM, elevated dopamine neuron population activity in the ventral tegmental area and neuronal activity in the ventral hippocampus, using in vivo electrophysiological recordings.

RESULTS

Our findings demonstrated that both acute and chronic administration of NIC significantly improved deficits in prepulse inhibition of startle and novel object recognition among MAM rats and normalized elevated ventral tegmental area and ventral hippocampal neuronal activity in these animals.

CONCLUSION

Together, these findings of NIC-induced improvement of deficits lend support for a "self-medication" hypothesis behind increased cigarette smoking in SCZ and illustrate the potential utility of nicotinic modulation in future pharmacotherapies for certain SCZ symptoms.

The effects of JNJ-39393406 a positive allosteric nicotine modulator on mood and cognition in patients with unipolar depression: A double-blind, add-on, placebo-controlled trial

Nicotinic agonists have been shown to improve cognition and mood, but this improvement is inconsistent and short-lived, possibly due to receptor desensitization. Positive Allosteric Modulators (PAMs) of the nicotinic alpha-7 nicotinic-acetyl-choline receptor (a7nAChR) are hypothesized to change the configuration of the nicotinic receptor and delay desensitization, potentially increasing the duration of the activation of the receptor, and improving clinical efficacy. This was a randomized controlled trial (RCT) adding JNJ-39393406 9 (a PAM of the a7nAChR) (n=35) or placebo (n=36) to treatment as usual for two weeks in 71 patients with unipolar depression. Mixed models for repeated measures analyses were performed Primary outcome measures were the Brief Assessment of Cognition in Schizophrenia (BACS) composite and the Montgomery-Asperg Depression Rating Scale (MADRS) scores. The drug was well tolerated, however mixed models for repeated measures comparing JNJ-39393406 to placebo showed no significant difference for MADRS total score (p=0.78), BACS composite score (p=0.34), or any of the secondary outcome measures. There was no significant difference in adverse events between the study groups (p=0.44). In conclusion, this study's findings do not support the hypothesis that a positive nicotinic receptor modulator can improve cognitive or depressive symptomatology in patients with unipolar depression.

Smoking Is Related to Reduced Motivation, But Not Global Cognition, in the First Two Years of Treatment for First Episode Psychosis

Smoking is highly prevalent in people with psychotic disorders, even in the earliest phases of the illness. The neural mechanisms of nicotine dependence and psychosis overlap and may also be linked to deficits in neurocognition and motivation in psychosis. Both neurocognition and motivation are recognized as important clinical targets, though previous research examining the effects of smoking on these features has been inconsistent. Here, we examine the relationships between smoking status and neurocognition and motivation over the first two years of treatment for psychosis through a secondary analysis of the Recovery After an Initial Schizophrenia Episode-Early Treatment Program (RAISE-ETP) dataset. In a sample of 404 individuals with first-episode psychosis, we examined linear mixed-effects models with the group (smoker vs. non-smoker) by time (baseline, 12-month, 24-month) interaction as a predictor of global cognition and motivation. While all individuals showed enhanced global cognition and motivation over the 24-month course of treatment, non-smokers showed significantly greater gains in motivation. These changes in motivation also corresponded to improvements in functioning over the 24-month period. No significant effects of smoking were observed for global cognition. Our findings suggest that motivation and smoking cessation may be important early treatment targets for first-episode psychosis programs.

The two-way relationship between nicotine and cortical activity: a systematic review of neurobiological and treatment aspects

Nicotine intake and cortical activity are closely related, as they can influence each other. Nicotine is implicated in the induction and modification of cortical plasticity and excitability, whereas a change on cortical plasticity and excitability can also lead to a modification of the smoking behaviour of an individual. The aim of this systematic review was, on the one hand, to evaluate the effects of nicotinergic modulation on cortical excitability and plasticity, and, on the other hand, to assess if modifying the brain's excitability and plasticity could influence one's smoking behaviour. Two systematic literature searches in the PubMed/MEDLINE and PsycINFO databases were conducted. Studies focusing either on the impact of nicotinergic modulation on cortical activity or the treatment effect of non-invasive brain stimulation techniques (NIBS) on smoking behaviour were included. A total of 22 studies for the first systematic search and 35 studies for the second one were included after full-text screening. Nicotine's effect on cortical activity appeared to depend on smoking status of the individual. While deprived smokers seem to generally profit from nicotine consumption in terms of cortical excitability and plasticity, the contrary was true for non-smokers. Regarding the questions of how changes in cortical excitability can influence smoking behaviour, a trend points towards NIBS being a potential intervention technique for smoking cessation.

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.

The effects of acute nicotine administration on cognitive and early sensory processes in schizophrenia: a systematic review

Nicotine use, which is mostly done through smoking tobacco, is among the most burdensome comorbidities of schizophrenia. However, the ways in which nicotine affects the cognitive and early sensory alterations found in this illness are still debated. After conducting a systematic literature search, 29 studies were selected. These studies involve individuals with schizophrenia who underwent cognitive and/or early sensory function assessments after acute nicotine administration and include 560 schizophrenia subjects and 346 non-schizophrenia controls. The findings highlight that a single dose of nicotine can improve a range of cognitive functions in schizophrenia subjects, such as attention, working memory, and executive functions, with attention being the most responsive domain. In addition, nicotine can modulate early detection of changes in the sensory environment at both the auditory and visual levels. Nevertheless, effects vary strongly depending on the type of neuropsychological assessment and nicotine intake conditions used in each study. The current findings suggest the need to consider a potential decrease of cognitive and early sensory performance when patients with schizophrenia quit smoking.

Differential Effects of Nicotine and Nicotine Withdrawal on Fear Conditioning in Male Rats

BACKGROUND

Tobacco use is prevalent in individuals who are routinely exposed to stress. However, little is known about how nicotine affects responses to trauma. We examined in rats how nicotine exposure affects fear conditioning, a procedure often used to study stress-related psychiatric illness.

METHODS

We examined 2 methods of nicotine exposure: self-administration, modeling voluntary use, and experimenter-programmed subcutaneous administration, modeling medicinal administration (nicotine patch). For self-administered nicotine, rats trained to self-administer nicotine i.v. were fear conditioned (via light cue preceding foot-shock) either immediately after a 12-hour self-administration session or 12 hours later during a period with somatic signs of nicotine withdrawal. For experimenter-delivered nicotine, rats were conditioned after 1-21 days of nicotine delivered by programmable (12 hours on) subcutaneous mini-pumps. Tests to evaluate acoustic startle responses to the conditioning environment (context-potentiated startle) and in the presence or absence of the light cue (fear-potentiated startle) occurred after a 10-day period.

RESULTS

Rats fear conditioned immediately after nicotine self-administration showed reduced responses to the shock-associated context, whereas those trained during nicotine withdrawal showed exaggerated responses. Experimenter-programmed nicotine produced effects qualitatively similar to those seen with self-administered nicotine.

CONCLUSIONS

Self-administration or experimenter-programmed delivery of nicotine immediately before exposure to aversive events can reduce conditioned fear responses. In contrast, exposure to aversive events during nicotine withdrawal exacerbates fear responses. These studies raise the possibility of developing safe and effective methods to deliver nicotine or related drugs to mitigate the effects of stress while also highlighting the importance of preventing withdrawal in nicotine-dependent individuals.

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.

Characterization of Amphetamine, Methylphenidate, Nicotine, and Atomoxetine on Measures of Attention, Impulsive Action, and Motivation in the Rat: Implications for Translational Research

Amphetamine (AMP), methylphenidate (MPH), and atomoxetine (ATX) are approved treatments for ADHD, and together with nicotine (NIC), represent pharmacological agents widely studied on cognitive domains including attention and impulsive action in humans. These agents thus represent opportunities for clinical observation to be reinvestigated in the preclinical setting, i.e., reverse translation. The present study investigated each drug in male, Long Evans rats trained to perform either (1) the five-choice serial reaction time task (5-CSRTT), (2) Go/NoGo task, or (3) a progressive ratio (PR) task, for the purpose of studying each drug on attention, impulsive action and motivation. Specific challenges were adopted in the 5-CSRTT designed to tax attention and impulsivity, i.e., high frequency of stimulus presentation (sITI), variable reduction in stimulus duration (sSD), and extended delay to stimulus presentation (10-s ITI). Initially, performance of a large (> 80) cohort of rats in each task variant was conducted to examine performance stability over repeated challenge sessions, and to identify subgroups of "high" and "low" attentive rats (sITI and sSD schedules), and "high" and "low" impulsives (10-s ITI). Using an adaptive sequential study design, the effects of AMP, MPH, ATX, and NIC were examined and contrasting profiles noted across the tests. Both AMP (0.03-0.3 mg/kg) and MPH (1-6 mg/kg) improved attentional performance in the sITI but not sSD or 10-s ITI condition, NIC (0.05-0.2 mg/kg) improved accuracy across all conditions. ATX (0.1-1 mg/kg) detrimentally affected performance in the sITI and sSD condition, notably in "high" performers. In tests of impulsive action, ATX reduced premature responses notably in the 10-s ITI condition, and also reduced false alarms in Go/NoGo. Both AMP and NIC increased premature responses in all task variants, although AMP reduced false alarms highlighting differences between these two measures of impulsive action. The effect of MPH was mixed and appeared baseline dependent. ATX reduced break point for food reinforcement suggesting a detrimental effect on motivation for primary reward. Taken together these studies highlight differences between AMP, MPH, and ATX which may translate to their clinical profiles. NIC had the most reliable effect on attentional accuracy, whereas ATX was reliably effective against all tests of impulsive action.

Nicotine dependence (trait) and acute nicotinic stimulation (state) modulate attention but not inhibitory control: converging fMRI evidence from Go-Nogo and Flanker tasks

Cognitive deficits during nicotine withdrawal may contribute to smoking relapse. However, interacting effects of chronic nicotine dependence and acute nicotine withdrawal on cognitive control are poorly understood. Here we examine the effects of nicotine dependence (trait; smokers (n = 24) vs. non-smoking controls; n = 20) and acute nicotinic stimulation (state; administration of nicotine and varenicline, two FDA-approved smoking cessation aids, during abstinence), on two well-established tests of inhibitory control, the Go-Nogo task and the Flanker task, during fMRI scanning. We compared performance and neural responses between these four pharmacological manipulations in a double-blind, placebo-controlled crossover design. As expected, performance in both tasks was modulated by nicotine dependence, abstinence, and pharmacological manipulation. However, effects were driven entirely by conditions that required less inhibitory control. When demand for inhibitory control was high, abstinent smokers showed no deficits. By contrast, acutely abstinent smokers showed performance deficits in easier conditions and missed more trials. Go-Nogo fMRI results showed decreased inhibition-related neural activity in right anterior insula and right putamen in smokers and decreased dorsal anterior cingulate cortex activity on nicotine across groups. No effects were found on inhibition-related activity during the Flanker task or on error-related activity in either task. Given robust nicotinic effects on physiology and behavioral deficits in attention, we are confident that pharmacological manipulations were effective. Thus findings fit a recent proposal that abstinent smokers show decreased ability to divert cognitive resources at low or intermediate cognitive demand, while performance at high cognitive demand remains relatively unaffected, suggesting a primary attentional deficit during acute abstinence.

Neonatal 6-OHDA Lesion Model in Mouse Induces Cognitive Dysfunctions of Attention-Deficit/Hyperactivity Disorder (ADHD) During Young Age

Attention-deficit/hyperactivity disorder (ADHD) is a syndrome characterized by impaired attention, impulsivity and hyperactivity in children. These symptoms are often maintained in adults. During adolescence, prefrontal cortex develops connectivity with other brain regions to engage executive functions such as, latent inhibition, attention and inhibitory control. In our previous work, we demonstrated the validity of the neonatal 6-Hydroxydopamine (6-OHDA) mouse model, a classical neurodevelopmental model mimicking major symptoms of the human ADHD pathology. In order to evaluate pathological forms of executive functions and impulsive behavior in 6-OHDA mice during young age, we first tested latent inhibition (LI) after weaning, and then we evaluated the impulsive behavior using a cliff avoidance reaction test. Our results demonstrated that 6-OHDA mice showed disruption in latent inhibition, suggesting a deficit in selective attention, and displayed repetitive peering-down behavior, indicating a maladaptive impulsive behavior. Subsequently, to assess impulsivity and attention in young mice, we performed a modified 5-choice serial reaction time task test (5-CSRTT), optimizing the degree of food restriction for young animals and shortening the training duration. This test allowed us to demonstrate a deficit in inhibitory control and a loss of accuracy of 6-OHDA mice in the 5-CSRTT. In conclusion, we demonstrated that the 6-OHDA mouse model reproduces human symptoms of ADHD in childhood and early adulthood periods, as seen in human. Taken together, the 6-OHDA mouse model will be useful alongside other animal models to understand the neurobiological mechanisms underlying complex, heterogeneous neurological disorders.

Brief, Web-Based Interventions to Motivate Smokers With Schizophrenia: Randomized Trial

BACKGROUND

In-person motivational interventions increase engagement with evidence-based cessation treatments among smokers with schizophrenia, but access to such interventions can be limited because of workforce shortages and competing demands in mental health clinics. The use of digital technology to deliver interventions can increase access, but cognitive impairments in schizophrenia may impede the use of standard digital interventions. We developed an interactive, multimedia, digital motivational decision support system for smokers with schizophrenia (Let's Talk About Smoking). We also digitalized a standard educational pamphlet from the National Cancer Institute (NCI Education). Both were tailored to reduce cognitive load during use.

OBJECTIVE

We conducted a randomized trial of Let's Talk About Smoking versus NCI Education to test whether the interactive motivational intervention was more effective and more appealing than the static educational intervention for increasing use of smoking cessation treatment, quit attempts, and abstinence among smokers with schizophrenia, accounting for the level of cognitive functioning.

METHODS

Adult smokers with schizophrenia (n=162) were enrolled in the study from 2014 to 2015, randomly assigned to intervention condition, and assessed in person at 3- and 6-month follow-ups. Interventions were delivered on a laptop computer in a single session. All participants had access to standard, community-delivered cessation treatments during follow-up. Multivariate models were used to evaluate outcomes.

RESULTS

Treatment initiation outcomes were not different between intervention conditions (27/84 [32%] for Let's Talk About Smoking vs 36/78 [46%] for NCI Education; odds ratio [OR] 0.71 [95% CI 0.37-1.33]); 38.9% (63/162) of participants initiated treatment. Older age (OR 1.03 [95% CI 1.00-1.07]; P=.05), higher education (OR 1.21 [95% CI 1.04-1.41]; P=.03), and fewer positive symptoms (OR 0.87 [95% CI 0.80-0.96]; P=.01) predicted cessation treatment initiation, whereas level of cognition did not. The mean satisfaction and usability index score was higher for Let's Talk About Smoking versus NCI Education (8.9 [SD 1.3] vs 8.3 [SD 2.1]; t120.7=2.0; P=.045). Quit attempts (25/84, 30% vs 36/78, 46%; estimate [Est]=-0.093, SE 0.48; P=.85) and abstinence (1/84, 1% vs 6/78, 7%; χ21=3.4; P=.07) were not significantly different between intervention conditions. Cognitive functioning at baseline (Est=1.47, SE 0.47; P=.002) and use of any behavioral or medication cessation treatment (Est=1.43, SE 0.47; P=.003) predicted quit attempts with self-reported abstinence over the 6-month follow-up.

CONCLUSIONS

The interactive, multimedia intervention was not more effective than the static, text-based intervention among smokers with schizophrenia. Both tailored digital interventions resulted in levels of treatment engagement and quit attempts that were similar to findings from previous studies of in-person interventions, confirming the potential role of digital interventions to educate and motivate smokers with schizophrenia to use cessation treatment and to quit smoking. These findings indicate that additional cessation treatment is needed after brief education or motivational interventions, and that cessation treatment should be adjusted for people with cognitive impairment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02086162; https://clinicaltrials.gov/show/NCT02086162.

Experiences of Tobacco Use among Chinese Individuals with Schizophrenia in Community-Based Residential Settings: A Qualitative Study

Although there is a high prevalence of smoking among individuals with schizophrenia, no previous attempt has been made to explore experiences of tobacco use and cessation within a Chinese sample of this population. A qualitative descriptive study was conducted to explore through the use of individual and semi-structured interviews the experiences of tobacco use and quitting in a sample Chinese population with schizophrenia. Twenty-three eligible participants with schizophrenia who currently smoke were recruited from three community residential mental health service settings. Four main themes representing the experiences of the participants were uncovered in this study: (1) smoking and illness; (2) environment and culture; (3) reasons for smoking; and (4) beliefs about cessation methods. The findings indicated that the participants considered the disease to be far more harmful than smoking, and perceived many benefits to smoking. Although some thought of quitting at times, most gave up the idea or failed to quit due to internal factors such as disease-related suffering, the use of an avoidance coping strategy, and a lack of cessation support. The most notable finding concerns the use of avoidance coping by the participants, who relied on smoking as a way to avoid the suffering brought about by the disease.

The Utility of the CPT in the Diagnosis of ADHD in Individuals with Substance Abuse: A Systematic Review

BACKGROUND

Early identification of attention-deficit/hyperactivity disorder (ADHD) in individuals with substance use disorders (SUD) is important because ADHD has an adverse effect on the development and course of SUD. Given the limited validity of self-report measures of ADHD in individuals with SUD, it is important to investigate the utility of the continuous performance test (CPT) in classifying ADHD in adults with SUD.

OBJECTIVE

This review aims to examine the quantitative similarities and differences in CPT performance of adults with ADHD, SUD, and their comorbidity to determine if a distinct neurocognitive profile exists for each.

METHOD

A systematic review of CPT studies that included patients with the comorbidity of ADHD and SUD and a comparison group of one of the disorders alone was conducted. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used.

RESULTS

Eight studies were identified with sample sizes ranging from n = 17 to n = 386. The comorbidity of ADHD and SUD was, mostly, not associated with higher rates of commission and omission errors than either disorder alone. However, the comorbidity of ADHD and SUD was more likely to be associated with increased deficits in response time variability compared with individuals with ADHD alone.

CONCLUSIONS

This review highlights the shortage of large-scale CPT research involving patients with ADHD and SUD. The CPT might be sensitive to attentional deficits, but it lacks specificity for the classification of adult ADHD, SUD, or their comorbidity, and the CPT is thus not useful in discriminating comorbid ADHD and SUD from either disorder alone. Future CPT research should explore whether specific attentional deficits account for the development and persistence of SUD. Such research should also reach beyond traditional CPT measures and include other cognitive and behavioral deficits that were associated with ADHD, such as distractibility and hyperactivity.

Acute administration of nicotine does not enhance cognitive functions

Chronic smokers often claim that smoking improves their cognitive abilities, such as concentration. However, scientific evidence to support this claim is scarce. Previous studies gave inconclusive results, and some of them had significant methodological flaws. Therefore, the aim of this study was to test whether smoking a single cigarette affects performance across several cognitive domains. It included a group of 22 occasional smokers aged 19-29 years. Attention, working memory, and visuospatial reasoning were assessed using a within-subjects design with a control setting. There were two separate testing sessions two days apart. Half the group started with experimental and the other half with control setting. In the experimental setting, the participants completed the first block of tasks, smoked one cigarette (with a nicotine yield of 0.5 mg), and then completed the second block of tasks. In the control setting, the procedure was the same, except that the participants had a glass of water instead of a cigarette. Repeated measures ANOVA showed no significant effects of cigarette smoking on either reaction time rates or accuracy on any of the three cognitive domains. These results suggest that, at least among young, occasional smokers, smoking does not affect cognition and the claims of its improvement are probably a result of some sort of cognitive bias.

Nicotine effects on cognitive remediation training outcome in people with schizophrenia: A pilot study

Cognitive remediation training can alleviate cognitive impairment associated with schizophrenia, but the impact is limited by small effect sizes. The present study aimed at augmenting training effects by administering nicotine prior to training sessions. Twenty-five people with schizophrenia were enrolled in a 10-week, 5 days/week, computerized cognitive training regimen. Participants were randomized to two treatment groups: nicotine or placebo. Every Monday and Thursday, the nicotine group received a nicotine lozenge before the training, and the placebo group a placebo lozenge. Outcome measurements were conducted on a no-lozenge day in weeks 0, 4, 7, and 10, and at 4-week follow-up. The MATRICS Consensus Cognitive Battery composite score improved over time, but there was no group difference in this effect. A significant group difference emerged over time in the reasoning/problem solving sub-domain: the placebo group improved but not the nicotine group, suggesting that nicotine exposure negatively impacted training benefits on executive control processes. There were no effects on psychiatric symptoms. However, significant improvements were seen across groups on the Quality of Life Scale and the Cognitive Assessment Interview, measuring real-life functional outcome. In conclusion, the present study failed to find evidence that nicotine exposure during cognitive remediation training may potentiate training benefits.

Reasons for smoking and barriers to cessation among adults with serious mental illness: A qualitative study

AIMS

Most research into reasons for smoking among adults with serious mental illness (SMI) has focused on reasons related to SMI symptoms. The current study reports reasons for smoking and barriers to cessation that are both related and unrelated to SMI symptoms among adults with SMI.

METHODS

Four focus groups were conducted among current smokers receiving outpatient care for a psychotic disorder in 2017 (N = 24). Participants were asked why they currently smoke and their barriers to quitting smoking.

RESULTS

Smoking as a coping mechanism and to self-medicate SMI symptoms were reasons for current smoking and barriers to cessation. Avoidance of other unhealthy behaviors, routine, and enjoyment emerged as reasons for smoking and barriers to cessation that were unrelated to mental illness.

CONCLUSION

Consideration of factors that are both related and unrelated to SMI symptoms in smoking cessation interventions and brief cessation counseling may improve cessation success in this population.

Mitochondria as a possible target for nicotine action

Mitochondria are multifunctional and dynamic organelles deeply integrated into cellular physiology and metabolism. Disturbances in mitochondrial function are involved in several disorders such as neurodegeneration, cardiovascular diseases, metabolic diseases, and also in the aging process. Nicotine is a natural alkaloid present in the tobacco plant which has been well studied as a constituent of cigarette smoke. It has also been reported to influence mitochondrial function both in vitro and in vivo. This review presents a comprehensive overview of the present knowledge of nicotine action on mitochondrial function. Observed effects of nicotine exposure on the mitochondrial respiratory chain, oxidative stress, calcium homeostasis, mitochondrial dynamics, biogenesis, and mitophagy are discussed, considering the context of the experimental design. The potential action of nicotine on cellular adaptation and cell survival is also examined through its interaction with mitochondria. Although a large number of studies have demonstrated the impact of nicotine on various mitochondrial activities, elucidating its mechanism of action requires further investigation.

Improving cognitive training for schizophrenia using neuroplasticity enhancers: Lessons from decades of basic and clinical research

Mounting evidence indicates that schizophrenia is a disorder that stems from maladaptive plasticity within neural circuits and produces broad cognitive deficits leading to loss of autonomy. A large number of studies have identified abnormalities spanning many neurotransmitter systems in schizophrenia, and as a result, a variety of drugs have been developed to attempt to treat these abnormalities and enhance cognition. Unfortunately, positive results have been limited so far. This may be in part because the scope of abnormalities in the schizophrenic brain requires a treatment capable of engaging many different neurotransmitter systems. One approach to achieving this kind of treatment has been to use neuroplasticity-based computerized cognitive training programs to stimulate the formation of more adaptive circuits. Although the number of studies implementing this approach has increased exponentially in recent years, effect sizes for cognitive gains have been modest and adherence to treatment remains an important challenge in many studies, as patients are often required to train for 40 h or more. In the present paper, we argue that cognitive training protocols will benefit from the addition of cognitive enhancers to produce more robust and longer lasting targeted neuroplasticity. Indeed, recent data from animal studies have provided support for combining plasticity-enhancing drugs with tailored behavioral training paradigms to restore normal function within dysfunctioning neural circuits. The advantages and challenges of applying this approach to patients with schizophrenia will be discussed.

Alterations in resting-state functional connectivity in substance use disorders and treatment implications

Substance use disorders (SUD) are diseases of the brain, characterized by aberrant functioning in the neural circuitry of the brain. Resting state functional connectivity (rsFC) can illuminate these functional changes by measuring the temporal coherence of low-frequency fluctuations of the blood oxygenation level-dependent magnetic resonance imaging signal in contiguous or non-contiguous regions of the brain. Because this data is easy to obtain and analyze, and therefore fairly inexpensive, it holds promise for defining biological treatment targets in SUD, which could help maximize the efficacy of existing clinical interventions and develop new ones. In an effort to identify the most likely "treatment targets" obtainable with rsFC we summarize existing research in SUD focused on 1) the relationships between rsFC and functionality within important psychological domains which are believed to underlie relapse vulnerability 2) changes in rsFC from satiety to deprived or abstinent states 3) baseline rsFC correlates of treatment outcome and 4) changes in rsFC induced by treatment interventions which improve clinical outcomes and reduce relapse risk. Converging evidence indicates that likely "treatment target" candidates, emerging consistently in all four sections, are reduced connectivity within executive control network (ECN) and between ECN and salience network (SN). Other potential treatment targets also show promise, but the literature is sparse and more research is needed. Future research directions include data-driven prediction analyses and rsFC analyses with longitudinal datasets that incorporate time since last use into analysis to account for drug withdrawal. Once the most reliable biological markers are identified, they can be used for treatment matching, during preliminary testing of new pharmacological compounds to establish clinical potential ("target engagement") prior to carrying out costly clinical trials, and for generating hypotheses for medication repurposing.

Impact of Substance Use Disorder Pharmacotherapy on Executive Function: A Narrative Review

Substance use disorders are chronic, relapsing, and harmful conditions characterized by executive dysfunction. While there are currently no approved pharmacotherapy options for stimulant and cannabis use disorders, there are several evidence-based options available to help reduce symptoms during detoxification and aid long-term cessation for those with tobacco, alcohol and opioid use disorders. While these medication options have shown clinical efficacy, less is known regarding their potential to enhance executive function. This narrative review aims to provide a brief overview of research that has investigated whether commonly used pharmacotherapies for these substance use disorders (nicotine, bupropion, varenicline, disulfiram, acamprosate, nalmefene, naltrexone, methadone, buprenorphine, and lofexidine) effect three core executive function components (working memory, inhibitory control and cognitive flexibility). While pharmacotherapy-induced enhancement of executive function may improve cessation outcomes in dependent populations, there are limited and inconsistent findings regarding the effects of these medications on executive function. We discuss possible reasons for the mixed findings and suggest some future avenues of work that may enhance the understanding of addiction pharmacotherapy and cognitive training interventions and lead to improved patient outcomes.

Increased Connectivity Between the Nucleus Accumbens and the Default Mode Network in Patients With Schizophrenia During Cigarette Cravings

Objective: Compared to the general population, tobacco smoking cessation rates are lower in populations with schizophrenia. Unfortunately, the potential neurophysiologic mechanisms underlying these low cessation rates in schizophrenia have been seldom studied using functional neuroimaging. Recently, it has been shown that tobacco cravings are increased in smokers with schizophrenia compared to smokers with no comorbid psychiatric disorder. Given the critical role of the brain reward system in the neurobiology of addiction, we sought to examine the functional connectivity of core regions of this system in smokers with schizophrenia during the viewing of appetitive smoking cues. Methods: Smokers with (n = 18) and without (n = 24) schizophrenia were scanned using functional magnetic resonance imaging while viewing appetitive cigarette images. Functional connectivity analyses were performed using the bilateral nucleus accumbens as the seed regions. Results: Smokers with schizophrenia and smokers with no psychiatric comorbidity did not differ in subjective cravings in response to appetitive smoking cues. However, in smokers with schizophrenia relative to control smokers, we found an increased connectivity between the nucleus accumbens and regions involved in the default mode network (e.g., middle temporal gyrus and precuneus), which are involved in self-referential processes. Moreover, a positive correlation was observed between the left nucleus accumbens and left middle temporal gyrus connectivity and cigarette cravings across both groups of smokers. Conclusions: These results highlight a key role of the nucleus accumbens in cigarette craving in schizophrenia and suggest that the subjective valuation of cigarette cues is increased in this population. Similar neurofunctional studies on cravings for other psychoactive substances in schizophrenia are warranted.

The past and future of novel, non-dopamine-2 receptor therapeutics for schizophrenia: A critical and comprehensive review

Since the discovery of chlorpromazine in the 1950's, antipsychotic drugs have been the cornerstone of treatment of schizophrenia, and all attenuate dopamine transmission at the dopamine-2 receptor. Drug development for schizophrenia since that time has led to improvements in side effects and tolerability, and limited improvements in efficacy, with the exception of clozapine. However, the reasons for clozapine's greater efficacy remain unclear, despite the great efforts and resources invested therewith. We performed a comprehensive review of the literature to determine the fate of previously tested, non-dopamine-2 receptor experimental treatments. Overall we included 250 studies in the review from the period 1970 to 2017 including treatments with glutamatergic, serotonergic, cholinergic, neuropeptidergic, hormone-based, dopaminergic, metabolic, vitamin/naturopathic, histaminergic, infection/inflammation-based, and miscellaneous mechanisms. Despite there being several promising targets, such as allosteric modulation of the NMDA and α7 nicotinic receptors, we cannot confidently state that any of the mechanistically novel experimental treatments covered in this review are definitely effective for the treatment of schizophrenia and ready for clinical use. We discuss potential reasons for the relative lack of progress in developing non-dopamine-2 receptor treatments for schizophrenia and provide recommendations for future efforts pursuing novel drug development for schizophrenia.

Neurobiological Determinants of Tobacco Smoking in Schizophrenia

Purpose of review: To provide an overview of the underlying neurobiology of tobacco smoking in schizophrenia, and implications for treatment of this comorbidity. Recent findings: Explanations for heavy tobacco smoking in schizophrenia include pro-cognitive effects of nicotine, and remediation of the underlying pathophysiology of schizophrenia. Nicotine may ameliorate neurochemical deficits through nicotine acetylcholine receptors (nAChRs) located on the dopamine, glutamate, and GABA neurons. Neurophysiological indices including electroencephalography, electromyography, and smooth pursuit eye movement (SPEM) paradigms may be biomarkers for underlying neuronal imbalances that contribute to the specific risk of tobacco smoking initiation, maintenance, and difficulty quitting within schizophrenia. Moreover, several social factors including socioeconomic factors and permissive smoking culture in mental health facilities, may contribute to the smoking behaviors (initiation, maintenance, and inability to quit smoking) within this disorder. Summary: Tobacco smoking may alleviate specific symptoms associated with schizophrenia. Understanding the neurobiological underpinnings and psychosocial determinants of this comorbidity may better explain these potential beneficial effects, while also providing important insights into effective treatments for smoking cessation.

Efficacy of different types of cognitive enhancers for patients with schizophrenia: a meta-analysis

Cognitive impairment is a core feature of schizophrenia, which is predictive for functional outcomes and is, therefore, a treatment target in itself. Yet, literature on efficacy of different pharmaco-therapeutic options is inconsistent. This quantitative review provides an overview of studies that investigated potential cognitive enhancers in schizophrenia. We included pharmacological agents, which target different neurotransmitter systems and evaluated their efficacy on overall cognitive functioning and seven separate cognitive domains. In total, 93 studies with 5630 patients were included. Cognitive enhancers, when combined across all different neurotransmitter systems, which act on a large number of different mechanisms, showed a significant (yet small) positive effect size of 0.10 (k = 51, p = 0.023; 95% CI = 0.01 to 0.18) on overall cognition. Cognitive enhancers were not superior to placebo for separate cognitive domains. When analyzing each neurotransmitter system separately, agents acting predominantly on the glutamatergic system showed a small significant effect on overall cognition (k = 29, Hedges’ g = 0.19, p = 0.01), as well as on working memory (k = 20, Hedges’ g = 0.13, p = 0.04). A sub-analysis of cholinesterase inhibitors (ChEI) showed a small effect on working memory (k = 6, Hedges’ g = 0.26, p = 0.03). Other sub-analyses were positively nonsignificant, which may partly be due to the low number of studies we could include per neurotransmitter system. Overall, this meta-analysis showed few favorable effects of cognitive enhancers for patients with schizophrenia, partly due to lack of power. There is a lack of studies involving agents acting on other than glutamatergic and cholinergic systems, especially of those targeting the dopaminergic system.

Phase IIb Trial of an α7 Nicotinic Receptor Partial Agonist With and Without Nicotine Patch for Withdrawal-Associated Cognitive Deficits and Tobacco Abstinence

PURPOSE/BACKGROUND

The objective of this study was to determine whether a novel α7 nicotinic acetylcholine receptor partial agonist improves cognition during nicotine withdrawal and improves abstinence rates. To do so, the effect of the α7 nicotinic acetylcholine receptor partial agonist, encenicline, on cognition and abstinence was evaluated when given as monotherapy and when combined with transdermal nicotine patch (nicotine replacement therapy [NRT]).

METHODS

Adult daily smokers, n = 160, who were motivated to quit smoking completed cognitive testing at satiated baseline and after overnight abstinence and then were randomized to receive a 12-week trial of encenicline 1 mg twice daily or identical placebo the day of the overnight abstinent cognitive testing. In the first 6 weeks of the 12-week encenicline administration, participants were also randomized to 6 weeks of NRT patch or placebo patch. Primary outcomes were cognition during abstinence and 7-day point-prevalence abstinence at week 12.

RESULTS

No beneficial effects of encenicline were observed on cognition or abstinence when compared with placebo or when combined with NRT compared with placebo capsule + NRT. Of the 4 conditions, abstinence rates were lowest among those assigned to encenicline alone.

CONCLUSIONS

Beneficial effects of NRT were observed on cognitive and abstinence outcomes when combined with encenicline compared with encenicline plus placebo patch. Addition of NRT to encenicline improved odds of abstinence approximately 3-fold compared with encenicline plus placebo patch. We conclude that encenicline, 1 mg/d, did not improve abstinence-associated cognitive impairment or abstinence rates as monotherapy or adjunctive therapy to NRT patch.

Existing and emerging smoking cessation options for people with schizophrenia spectrum disorders

Tobacco cigarette addiction is a deeply entrenched behavior among people with Schizophrenia Spectrum Disorders, and consequently these individuals die an average of 25 years earlier than the general population. The aim of this review was to evaluate the state-of-the-science focused on cessation and reduction interventions for people with SSD. We searched peer-reviewed articles from medline, psycinfo, web of science, scopus, and cochrane library, about cessation interventions for people with SSD. The search was carried out by combining an exhaustive list of terms denoting schizophrenic disorder and smoking cessation treatment. The review search period was limited from January 2000-November 2018, 260 studies were identified and a total of 24 of studies were included in the final review. This review demonstrates the vulnerability of smokers with SSD and underscores the need for research in these areas with large enough sample sizes to detect treatment effects: 1) outcomes using and comparing standard treatments 2) long-term cessation/reduction outcomes 3) flexible treatment options 4) more research to develop the evidence-base for e-cigarettes intervention.

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.

Nicotine-induced activation of caudate and anterior cingulate cortex in response to errors in schizophrenia

BACKGROUND

Nicotine improves attention and processing speed in individuals with schizophrenia. Few studies have investigated the effects of nicotine on cognitive control. Prior functional magnetic resonance imaging (fMRI) research demonstrates blunted activation of dorsal anterior cingulate cortex (dACC) and rostral anterior cingulate cortex (rACC) in response to error and decreased post-error slowing in schizophrenia.

METHODS

Participants with schizophrenia (n = 13) and healthy controls (n = 12) participated in a randomized, placebo-controlled, crossover study of the effects of transdermal nicotine on cognitive control. For each drug condition, participants underwent fMRI while performing the stop signal task where participants attempt to inhibit prepotent responses to "go (motor activation)" signals when an occasional "stop (motor inhibition)" signal appears. Error processing was evaluated by comparing "stop error" trials (failed response inhibition) to "go" trials. Resting-state fMRI data were collected prior to the task.

RESULTS

Participants with schizophrenia had increased nicotine-induced activation of right caudate in response to errors compared to controls (DRUG × GROUP effect: p _corrected < 0.05). Both groups had significant nicotine-induced activation of dACC and rACC in response to errors. Using right caudate activation to errors as a seed for resting-state functional connectivity analysis, relative to controls, participants with schizophrenia had significantly decreased connectivity between the right caudate and dACC/bilateral dorsolateral prefrontal cortices.

CONCLUSIONS

In sum, we replicated prior findings of decreased post-error slowing in schizophrenia and found that nicotine was associated with more adaptive (i.e., increased) post-error reaction time (RT). This proof-of-concept pilot study suggests a role for nicotinic agents in targeting cognitive control deficits in schizophrenia.

Assessment of the Association Between Cigarette Smoking and Cognitive Performance in Patients With Schizophrenia-Spectrum Disorders: A Case-Control Study

The prevalence of cigarette smoking is significantly higher in patients with schizophrenia compared to the general population. Schizophrenia is also characterized by cognitive impairments that can be detected in the premorbid phase of illness. However, studies addressing the association between cigarette smoking and cognition in patients with psychosis have provided mixed findings. Therefore, the aim of this study was to assess the relationship between tobacco smoking and cognitive performance in patients with schizophrenia. In this case-control study, we recruited 67 inpatients with schizophrenia (34 cigarette smokers) and 62 healthy controls (30 cigarette smokers) at two clinical sites (Wroclaw and Szczecin, Poland). Cognitive performance was examined using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Smoking dependence was determined using the Fagerström Test for Nicotine Dependence (FTND) and the pack-year index. Results show that, after adjustment for potential confounders, smokers with schizophrenia presented significantly lower scores on delayed memory tests compared to non-smokers with schizophrenia (F = 11.07, p = 0.002). In healthy controls, after adjustment for age, sex, and education level, smokers had significantly lower scores in immediate memory (47.1 ± 6.4 vs. 52.0 ± 4.0, F = 11.64, p = 0.001), visuospatial/constructional functions (34.8 ± 3.8 vs. 37.7 ± 1.8, F = 12.86, p = 0.001) and global cognition (177.0 ± 15.7 vs. 191.2 ± 14.0, F = 12.63, p = 0.001) compared to non-smokers. There were no significant correlations between FTND scores or pack-year index and cognitive performance neither in patient nor control group. Our results show that cigarette smoking is related to worse delayed memory performance in schizophrenia patients as well as deficits of immediate memory, visuospatial/constructional functions, and global cognition in controls. Longitudinal studies are required to establish causal interference between smoking and cognition in patients with schizophrenia.

Medications Used for Cognitive Enhancement in Patients With Schizophrenia, Bipolar Disorder, Alzheimer's Disease, and Parkinson's Disease

BACKGROUND/AIMS

Cognitive impairment, which frequently occurs in patients with schizophrenia, bipolar disorder, Alzheimer's disease, and Parkinson's disease, has a significant impact on the daily lives of both patients and their family. Furthermore, since the medications used for cognitive enhancement have limited efficacy, the issue of cognitive enhancement still remains a clinically unsolved challenge.

SAMPLING AND METHODS

We reviewed the clinical studies (published between 2007 and 2017) that focused on the efficacy of medications used for enhancing cognition in patients with schizophrenia, bipolar disorder, Alzheimer's disease, and Parkinson's disease.

RESULTS

Acetylcholinesterase inhibitors and memantine are the standard treatments for Alzheimer's disease and Parkinson's disease. Some studies have reported selective cognitive improvement in patients with schizophrenia following galantamine treatment. Newer antipsychotics, including paliperidone, lurasidone, aripiprazole, ziprasidone, and BL-1020, have also been reported to exert cognitive benefits in patients with schizophrenia. Dopaminergic medications were found to improve language function in patients with Parkinson's disease. However, no beneficial effects on cognitive function were observed with dopamine agonists in patients with schizophrenia. The efficacies of nicotine and its receptor modulators in cognitive improvement remain controversial, with the majority of studies showing that varenicline significantly improved the cognitive function in schizophrenic patients. Several studies have reported that N-methyl-d-aspartate glutamate receptor (NMDAR) enhancers improved the cognitive function in patients with chronic schizophrenia. NMDAR enhancers might also have cognitive benefits in patients with Alzheimer's disease or Parkinson's disease. Raloxifene, a selective estrogen receptor modulator, has also been demonstrated to have beneficial effects on attention, processing speed, and memory in female patients with schizophrenia.

CONCLUSION

Clinical trials with larger sample sizes evaluating comprehensive cognitive domains are warranted to examine the efficacy of medications in cognitive enhancement in patients with schizophrenia, bipolar disorder, Alzheimer's disease, and Parkinson's disease.

Tobacco smoking is associated with psychotic experiences in the general population of South London

BACKGROUND

The association between cigarette smoking and psychosis remains unexplained, but could relate to causal effects in both directions, confounding by socioeconomic factors, such as ethnicity, or use of other substances, including cannabis. Few studies have evaluated the association between cigarettes and psychotic experiences (PEs) in diverse, inner-city populations, or relationships with number of cigarettes consumed.

METHODS

We assessed associations and dose-response relationships between cigarette smoking and PEs in a cross-sectional survey of household residents (n = 1680) in South East London, using logistic regression to adjust for cannabis use, other illicit substances, and socioeconomic factors, including ethnicity.

RESULTS

We found association between any PEs and daily cigarette smoking, which remained following adjustment for age, gender, ethnicity, cannabis and use of illicit stimulant drugs (fully adjusted odds ratio 1.47, 95% confidence interval 1.01-2.15). Fully adjusted estimates for the association, and with number of PEs, increased with number of cigarettes smoked daily, implying a dose-response effect (p = 0.001 and <0.001, respectively). Odds of reporting any PEs in ex-smokers were similar to never-smokers.

CONCLUSIONS

In this diverse epidemiological sample, association between smoking and PEs was not explained by confounders such as cannabis or illicit drugs. Daily cigarette consumption showed a dose-response relationship with the odds of reporting PEs, and of reporting a greater number of PEs. There was no difference in odds of reporting PEs between ex-smokers and never-smokers, raising the possibility that the increase in PEs associated with smoking may be reversible.

Revisiting nicotine’s role in the ageing brain and cognitive impairment

Brain ageing is a complex process which in its pathologic form is associated with learning and memory dysfunction or cognitive impairment. During ageing, changes in cholinergic innervations and reduced acetylcholinergic tonus may trigger a series of molecular pathways participating in oxidative stress, excitotoxicity, amyloid-β toxicity, apoptosis, neuroinflammation, and perturb neurotrophic factors in the brain. Nicotine is an exogenous agonist of nicotinic acetylcholine receptors (nAChRs) and acts as a pharmacological chaperone in the regulation of nAChR expression, potentially intervening in age-related changes in diverse molecular pathways leading to pathology. Although nicotine has therapeutic potential, paradoxical effects have been reported, possibly due to its inverted U-shape dose-response effects or pharmacokinetic factors. Additionally, nicotine administration should result in optimum therapeutic effects without imparting abuse potential or toxicity. Overall, this review aims to compile the previous and most recent data on nicotine and its effects on cognition-related mechanisms and age-related cognitive impairment.

A Novel Multisensory Integration Task Reveals Robust Deficits in Rodent Models of Schizophrenia: Converging Evidence for Remediation via Nicotinic Receptor Stimulation of Inhibitory Transmission in the Prefrontal Cortex

Atypical multisensory integration is an understudied cognitive symptom in schizophrenia. Procedures to evaluate multisensory integration in rodent models are lacking. We developed a novel multisensory object oddity (MSO) task to assess multisensory integration in ketamine-treated rats, a well established model of schizophrenia. Ketamine-treated rats displayed a selective MSO task impairment with tactile-visual and olfactory-visual sensory combinations, whereas basic unisensory perception was unaffected. Orbitofrontal cortex (OFC) administration of nicotine or ABT-418, an α₄β₂ nicotinic acetylcholine receptor (nAChR) agonist, normalized MSO task performance in ketamine-treated rats and this effect was blocked by GABA_A receptor antagonism. GABAergic currents were also decreased in OFC of ketamine-treated rats and were normalized by activation of α₄β₂ nAChRs. Furthermore, parvalbumin (PV) immunoreactivity was decreased in the OFC of ketamine-treated rats. Accordingly, silencing of PV interneurons in OFC of PV-Cre mice using DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) selectively impaired MSO task performance and this was reversed by ABT-418. Likewise, clozapine-N-oxide-induced inhibition of PV interneurons in brain slices was reversed by activation of α₄β₂ nAChRs. These findings strongly imply a role for prefrontal GABAergic transmission in the integration of multisensory object features, a cognitive process with relevance to schizophrenia. Accordingly, nAChR agonism, which improves various facets of cognition in schizophrenia, reversed the severe MSO task impairment in this study and appears to do so via a GABAergic mechanism. Interactions between GABAergic and nAChR receptor systems warrant further investigation for potential therapeutic applications. The novel behavioral procedure introduced in the current study is acutely sensitive to schizophrenia-relevant cognitive impairment and should prove highly valuable for such research.

SIGNIFICANCE STATEMENT

Adaptive behaviors are driven by integration of information from different sensory modalities. Multisensory integration is disrupted in patients with schizophrenia, but little is known about the neural basis of this cognitive symptom. Development and validation of multisensory integration tasks for animal models is essential given the strong link between functional outcome and cognitive impairment in schizophrenia. We present a novel multisensory object oddity procedure that detects selective multisensory integration deficits in a rat model of schizophrenia using various combinations of sensory modalities. Moreover, converging data are consistent with a nicotinic-GABAergic mechanism of multisensory integration in the prefrontal cortex, results with strong clinical relevance to the study of cognitive impairment and treatment in schizophrenia.

Targeting neuronal dysfunction in schizophrenia with nicotine: Evidence from neurophysiology to neuroimaging

Patients with schizophrenia self-administer nicotine at rates higher than is self-administered for any other psychiatric illness. Although the reasons are unclear, one hypothesis suggests that nicotine is a form of 'self-medication' in order to restore normal levels of nicotinic signaling and target abnormalities in neuronal function associated with cognitive processes. This brief review discusses evidence from neurophysiological and neuroimaging studies in schizophrenia patients that nicotinic agonists may effectively target dysfunctional neuronal circuits in the illness. Evidence suggests that nicotine significantly modulates a number of these circuits, although relatively few studies have used modern neuroimaging techniques (e.g. functional magnetic resonance imaging (fMRI)) to examine the effects of nicotinic drugs on disease-related neurobiology. The neuronal effects of nicotine and other nicotinic agonists in schizophrenia remain a priority for psychiatry research.

Nicotinic modulation of salience network connectivity and centrality in schizophrenia

Although functional abnormalities of the salience network are associated with schizophrenia, the acute effects of nicotine on its function and network dynamics during the resting state in patients are poorly understood. In this study, the effects of a 7 mg nicotine patch (vs. placebo) on salience network connectivity were examined in 17 patients with schizophrenia and 19 healthy subjects. We hypothesized abnormal connectivity between the salience network and other major networks (e.g. executive network) in patients under placebo administration and amelioration of this difference after nicotine. We also examined effects of nicotine on betweenness centrality (a measure of the influence of a region on information transfer throughout the brain) and local efficiency (a measure of local information transfer) of the network. A hybrid independent component analysis (ICA)/seed-based connectivity approach was implemented in which the salience network was extracted by ICA and cortical network peaks (anterior cingulate cortex (ACC), left and right insula) were used as seeds for whole-brain seed-to-voxel connectivity analysis. Significant drug X diagnosis interactions were observed between the ACC seed and superior parietal lobule and ventrolateral prefrontal cortex. A significant interaction effect was also observed between the left insula seed and middle cingulate cortex. During placebo conditions, abnormal connectivity predicted negative symptom severity and lower global functioning in patients. A significant drug X diagnosis interaction was also observed for betweenness centrality of the ACC. These results suggest that nicotine may target abnormalities in functional connectivity between salience and executive network areas in schizophrenia as well as affect the ability of the salience network to act as an integrator of global signaling in the disorder.

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.

Maintenance pharmacotherapy normalizes the relapse curve in recently abstinent tobacco smokers with schizophrenia and bipolar disorder

OBJECTIVE

To compare the effect of maintenance pharmacotherapy on sustained abstinence rates between recently abstinent smokers with schizophrenia and bipolar disorder (SBD) and general population smokers without psychiatric illness.

METHOD

We performed a person-level, pooled analysis of two randomized controlled trials of maintenance varenicline, conducted in adult smokers with SBD and general population smokers, controlling for severity of dependence. Smokers abstinent after 12-weeks of open varenicline treatment were randomly assigned to ≥12-weeks maintenance varenicline or identical placebo.

RESULTS

In those assigned to maintenance placebo, the abstinence rate at week-24 was lower in those with SBD than for those without psychiatric illness (29.4±1.1% vs. 61.8±0.4%, OR:0.26, 95% CI: 0.13, 0.52, p<0.001). In smokers assigned to maintenance pharmacotherapy, however, there was no effect of diagnosis on abstinence rates at week-24 (87.2±0.8% vs. 81.9±0.2%, OR: 1.68, 95% CI: 0.53, 5.32, p=0.38). Time to first lapse was shortest in those with SBD assigned to maintenance placebo (Q1=12days, 95%CI: 4, 16), longer in those without psychiatric illness assigned to maintenance placebo (Q1=17days, 95%CI: 17, 29), still longer in general-population smokers assigned to maintenance varenicline (Q1=88, 95% CI:58,91, and longest in those with SBD who received maintenance varenicline (Q1>95days, 95%CI:non-est), (Χ²_3df=96.99, p<0.0001; all pairwise comparisons p<0.001).

CONCLUSIONS

Following a standard 12-week course of pharmacotherapy, people with schizophrenia and bipolar disorder were more likely to relapse to smoking without maintenance varenicline treatment. Maintenance pharmacotherapy could improve longer-term tobacco abstinence rates and reduce known smoking-related health disparities in those with SMI.

Effects of nicotine on response inhibition and interference control

Nicotine is a cholinergic agonist with known pro-cognitive effects in the domains of alerting and orienting attention. However, its effects on attentional top-down functions such as response inhibition and interference control are less well characterised. Here, we investigated the effects of 7 mg transdermal nicotine on performance on a battery of response inhibition and interference control tasks. A sample of N = 44 healthy adult non-smokers performed antisaccade, stop signal, Stroop, go/no-go, flanker, shape matching and Simon tasks, as well as the attentional network test (ANT) and a continuous performance task (CPT). Nicotine was administered in a within-subjects, double-blind, placebo-controlled design, with order of drug administration counterbalanced. Relative to placebo, nicotine led to significantly shorter reaction times on a prosaccade task and on CPT hits but did not significantly improve inhibitory or interference control performance on any task. Instead, nicotine had a negative influence in increasing the interference effect on the Simon task. Nicotine did not alter inter-individual associations between reaction times on congruent trials and error rates on incongruent trials on any task. Finally, there were effects involving order of drug administration, suggesting practice effects but also beneficial nicotine effects when the compound was administered first. Overall, our findings support previous studies showing positive effects of nicotine on basic attentional functions but do not provide direct evidence for an improvement of top-down cognitive control through acute administration of nicotine at this dose in healthy non-smokers.

Impaired Coupling between the Dorsomedial Prefrontal Cortex and the Amygdala in Schizophrenia Smokers Viewing Anti-smoking Images

BACKGROUND

Cigarette smoking is highly prevalent in schizophrenia and is one of the main factors contributing to the significantly decreased life expectancy in this population. Schizophrenia smokers, compared to their counterparts with no comorbid psychiatric disorder, are largely unaware and indifferent to the long-term negative consequences of cigarette smoking. The objective of this study was to determine, for the first time, if these meta-cognitive deficits are associated with neuro-functional alterations in schizophrenia smokers.

METHODS

Twenty-four smokers with no psychiatric disorder and 21 smokers with schizophrenia (DSM-IV criteria) were scanned using functional magnetic resonance imaging and exposed to anti-smoking images. Granger causality analyses were used to examine the effective connectivity between brain regions found to be significantly activated.

RESULTS

Across groups, potent activations were observed in the left ventro-lateral prefrontal cortex, the left amygdala (AMG), and the dorsomedial prefrontal cortex (dmPFC). Using the dmPFC as a seed region, we found an abnormal negative connectivity from the dmPFC to the AMG in schizophrenia smokers during the viewing of anti-smoking stimuli. This abnormal connectivity was not present during the viewing of aversive stimuli unrelated to tobacco.

DISCUSSION

Given the well-established roles of the dmPFC in social cognition and of the AMG in emotional processing, our results suggest that the relative indifference of schizophrenia smokers regarding the negative consequences of tobacco smoking could be explained by a cognitive-affective dissonance.