Genetics of smoking and depression

Cigarette smoking and risk of suicide in bipolar disorder: a systematic review

Objective

Bipolar disorder (BD) is a highly prevalent, chronic and recurrent mental illness. The smoking rates in patients with BD are much higher than those of the general population, and BD is associated with an increased risk of suicide. An association between smoking and suicidal behavior has been found in the general population, this systematic review examines whether there is evidence of an association between smoking and suicide behavior in patients with BD.

Method

A database search was carried out in Medline, Embase, The Cochrane Library, Scopus, and Web of Science, updated until December 31st, 2021, according to the 2020 PRISMA guidelines. We identified prospective and retrospective studies that included patients diagnosed with BD types I, II, and not otherwise specified, and in which smoking and suicidal behavior were correlated. Articles that focused exclusively on other mental disorders were excluded. The Ottawa-Newcastle scale was used to assess the methodological quality of the included articles.

Results

Fifteen articles (n = 7,395) met all the inclusion criteria. In nine of these articles, the authors found an association between smoking and suicidal behavior in BD, while in the remaining six articles, this association was not found. A great deal of variability was observed between articles, particularly in the measurement of suicidal behavior and tobacco consumption. The risk of bias, as assessed by the NOS, was high for most of the included articles, except for two papers, whose risk was low.

Conclusion

It was not possible to establish a clear relationship between tobacco use and the risk of suicide in BD patients due to the heterogeneity of the articles included in this systematic review, which had different sample sizes and methodological issues. However, both conditions are highly prevalent and have a negative impact on the prognosis of BD. Therefore, a systematic approach is needed, based on accurate measurement of a patient's smoking habits and their risk of suicidal behavior, in order to establish an appropriate therapeutic plan.

Additional information

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors and was registered on PROSPERO with the CRD42022301570 on January 21th 2022.

The association of smoking and smoking cessation with prevalent and incident symptoms of depression, anxiety, and sleep disturbance in the general population

BACKGROUND

Smoking is a well-established risk factor for chronic non-communicable diseases. However, the relationship between cigarette smoking and the risk of developing mental health conditions remains largely elusive. This study examined the relationship between cigarette smoking as well as smoking cessation and prevalent and incident symptoms of depression, anxiety, and sleep disturbance in the general population.

METHODS

In a cohort of 15,010 individuals from the Gutenberg Health Study (aged 35-74 years at enrollment), prevalent (at baseline from 2007 to 2012) and incident symptoms (at follow-up from 2012 to 2017) of depression, anxiety, and sleep disturbance were determined by validated questionnaires and/or medical records. Smoking status, pack-years of smoking in current and former smokers, and years since quitting smoking in former smokers were assessed by a standardized computer-assisted interview.

RESULTS

In multivariable logistic regression models with comprehensive adjustment for covariates, smoking status was independently associated with prevalent and incident symptoms of depression (Patient Health Questionnaire-9 ≥ 10), whereas this association was weaker for anxiety (Generalized Anxiety Disorder Scale-2 ≥ 3) and sleep disturbance (Patient Health Questionnaire-9 > 1). Among current and former smokers, smoking ≥30 or ≥10 pack-years, respectively, yielded in general the highest effect estimates. Smoking cessation was weakly associated with the prevalence and incidence of all outcomes, here consistent associations were observed for prevalent symptoms of depression.

LIMITATIONS

The observational nature of the study does not allow for causal inferences.

CONCLUSIONS

The results of the present study suggest that cigarette smoking is positively and that smoking cessation is negatively associated with symptoms of common mental health conditions, in particular of depression.

Association and Effects of Trauma, Displacement, and Illicit Drug Use on Psychiatric Illnesses in Khyber Pakhtunkhwa, Pakistan

Methodology

Data were accumulated from all patients seen in outpatient clinics from October to December 2020. No inpatients or community samples were included in the research. Verbal consent and approval from the local ethical committee were obtained beforehand. ICD-10 diagnostic criteria were used for all psychiatric diagnoses.

Results

A total of 500 patients were seen with a gender distribution of 51% females and 49% males. Patients aged 18-65 years comprised 79% of this sample; 52% had no formal education. A total of 43% lived in settled areas; 37% were from Afghanistan; 13% from tribal areas, and 7% were from the Swat region. Thirty percent had no medical history, and 40% reported no prior contact with psychiatric service. Anxiety spectrum disorders were more prevalent in females, and psychotic and drug-related illnesses were more prevalent in males. More than half the patients seen were considered fit for psychotherapy referral but could not engage because of the lack of such services near their homes. The significance of the results obtained was assessed using the Chi-squared test, using SPSS v.22. A p-value of less than 0.05 was considered significant.

Conclusion

Almost 40% of patients were admitted due to some form of trauma history, predominantly terrorism-related, displacement, and other losses. Two in three people reported current or past drug use, with tetrahydrocannabinol (THC) being the most commonly used drug, followed by sedatives, opioids/pain relief medications, amphetamines, or methamphetamine (ICE), and others (e.g., alcohol). There was a significant rise in drug use/trauma history in the tribal areas, Afghanistan, and Swat region compared to the local population of settled areas. Common psychiatric illnesses were as expected in the sample studied.

Prevalence of lifetime nonmedical opioid use among U.S. Health Center Patients aged 45 years and older with psychiatric disorders

OBJECTIVE

Despite recent concerns over the increase in opioid misuse among aging adults, little is known about the prevalence of lifetime nonmedical opioid use in underserved, vulnerable middle-aged and older patients with psychiatric disorders. This study aims to determine the lifetime prevalence of nonmedical opioid use among underserved, vulnerable U.S. adults aged ≥45 years with psychiatric disorders.

METHOD

A nationally representative sample (n = 3,294) was obtained from the 2014 Health Center Patient Survey which collects data on psychiatric disorders, opioid use, and other health information from underserved, vulnerable U.S. primary care populations. Predictor variables included self-reported panic disorder, generalized anxiety disorder, schizophrenia, or bipolar disorder. The outcome variable was self-reported lifetime nonmedical opioid use. Frequencies, counts, and unadjusted and adjusted logistic regression models were conducted with the cross-sectional survey dataset.

RESULTS

Patients with bipolar disorder had the highest lifetime nonmedical opioid use rate (20.8%), followed by schizophrenia (19.3%), panic disorder (16.5%), and generalized anxiety disorder (14.5%). Nonmedical opioid use was significantly associated with bipolar disorder (OR 3.46, 95% CI [1.33, 8.99]) and generalized anxiety disorder (OR 2.03 95% CI [1.08, 3.83]).

CONCLUSION

Our findings demonstrate a high prevalence of lifetime nonmedical opioid use in underserved, vulnerable middle-aged and older health center patients with psychiatric disorders. Given the prevalence, health center professionals should monitor, prevent, and treat new or reoccurring signs and symptoms of nonmedical opioid use in this high-risk group of aging patients with psychiatric disorders.

Is the Antidepressant Activity of Selective Serotonin Reuptake Inhibitors Mediated by Nicotinic Acetylcholine Receptors?

It is generally assumed that selective serotonin reuptake inhibitors (SSRIs) induce antidepressant activity by inhibiting serotonin (5-HT) reuptake transporters, thus elevating synaptic 5-HT levels and, finally, ameliorates depression symptoms. New evidence indicates that SSRIs may also modulate other neurotransmitter systems by inhibiting neuronal nicotinic acetylcholine receptors (nAChRs), which are recognized as important in mood regulation. There is a clear and strong association between major depression and smoking, where depressed patients smoke twice as much as the normal population. However, SSRIs are not efficient for smoking cessation therapy. In patients with major depressive disorder, there is a lower availability of functional nAChRs, although their amount is not altered, which is possibly caused by higher endogenous ACh levels, which consequently induce nAChR desensitization. Other neurotransmitter systems have also emerged as possible targets for SSRIs. Studies on dorsal raphe nucleus serotoninergic neurons support the concept that SSRI-induced nAChR inhibition decreases the glutamatergic hyperstimulation observed in stress conditions, which compensates the excessive 5-HT overflow in these neurons and, consequently, ameliorates depression symptoms. At the molecular level, SSRIs inhibit different nAChR subtypes by noncompetitive mechanisms, including ion channel blockade and induction of receptor desensitization, whereas α9α10 nAChRs, which are peripherally expressed and not directly involved in depression, are inhibited by competitive mechanisms. According to the functional and structural results, SSRIs bind within the nAChR ion channel at high-affinity sites that are spread out between serine and valine rings. In conclusion, SSRI-induced inhibition of a variety of nAChRs expressed in different neurotransmitter systems widens the complexity by which these antidepressants may act clinically.

Cigarette Smoking and Health-related Quality of Life in the General Population of Iran: Independent Associations According to Gender

Background:

Associations between smoking and health-related quality of life (HRQoL) in the general population remain unclear. The aim of the study was to quantify the independent associations between smoking and HRQoL.

Methods:

A cross-sectional population-based study was conducted on a total sample of 2197 participants obtained by multistage sampling to investigate the associations between smoking and HRQoL in the general population of southeast and southwest of Iran, aged 18–100 years in 2012–2013. Data were collected using a self-administrated of the 36-Item Short Form Survey (SF-36) questionnaire. Linear regression analyses were used to evaluate the associations between HRQoL and smoking while adjusting for various socioeconomic variables. In this study, P < 0.05 was considered a significant difference.

Results:

Out of the total of 2197 participants, current smokers and never smokers accounted for 13% and 87%, respectively. The mean HRQoL indices were for the current smokers 66.66 ± 17.86, and never smokers 71.35 ± 18.47 (P < 0.001). Independent associations between smoking and HRQoL were found, including negative associations (P < 0.001). The multivariate associations between smoking status and HRQoL, male smokers had a lower physical functioning, mental health, and total SF-36 score.

Conclusions:

Smoking was independently related to HRQoL, with large differences according to the gender. This study showed that there is a significant difference in the quality of life related to health in male smokers compared to male nonsmokers.

Association between depression and smoking: A global perspective from 48 low- and middle-income countries

BACKGROUND

Smoking is a leading modifiable cause of global morbidity and mortality. Research from high-income countries has found a high prevalence of smoking among people with depression and suggested that this may partially contribute to the increased premature mortality in this population. Limited research has investigated smoking behaviors across the depression spectrum and in low- and middle-income countries (LMICs). This study explored the relationship between depression and smoking across 48 LMICs.

METHODS

We conducted a cross-sectional, community-based study comprising 242,952 people [mean age 38.4 (SD = 16.1) years, 50.8% females] from the World Health Survey. Multivariable binary logistic regression analyses were performed to investigate the relationship between depression (including subsyndromal, brief depressive episode and depressive episodes) and smoking behaviours.

RESULTS

Overall, the prevalence of current smoking was lowest in Africa (13.5%) and highest in Asia (32.2%). A depressive episode was present in 6.7% of the sample. Compared to people without depression, subsyndromal depression, brief depressive episode, and depressive episodes were all significantly associated with smoking with similar effect sizes (ORs: 1.36-1.49). Countrywide meta-analysis found that the pooled overall OR for smoking in depression was 1.42 (95%CI = 1.32-1.52, I² = 39.7%). Furthermore, alcohol consumption and male gender were consistently associated with smoking across all regions and smoking was consistently less common in those who were wealthier and had a higher education.

CONCLUSION

These data suggest that the depression spectrum is consistently associated with high levels of smoking behaivours in LMICs. Given that most of the world's smokers reside in LMICs, future smoking cessation interventions are required to target people with depression.

Depression Among Non-Daily Smokers Compared to Daily Smokers and Never-Smokers in the United States: An Emerging Problem

INTRODUCTION

Depression is strongly associated with daily smoking. Yet, little is known about the association between depression and non-daily smoking. The aim of this study was to investigate the prevalence of past-year depression and changes in past-year depression over time among non-daily smokers, compared to daily smokers and never-smokers, overall and stratified by age, gender, income, nicotine dependence, and cigarettes per day.

METHODS

Data were drawn from the National Household Survey on Drug Use (NSDUH), an annual cross-sectional study of persons aged 12 and over (total study population N = 496 805). The prevalence of past-year depression was examined annually among non-daily smokers, daily smokers, and never-smokers from 2005 to 2013 using linear trend analyses.

RESULTS

Past-year depression was common among 10.10% of non-daily smokers, common among 10.78% of daily smokers, and 5.51% of never-smokers in 2013. The prevalence of depression increased from 2005 to 2013 among non-daily smokers (9.06% vs. 10.10%; p = .034) while there was no significant change in depression over time among daily smokers. Increases in depression among non-daily smokers occurred for both men and women and appear most pronounced youth, those smoking fewer cigarettes, and those without nicotine dependence.

CONCLUSIONS

The prevalence of depression among non-daily smokers was equivalent to daily smokers and nearly twice that among nonsmokers. Depression appears to be increasing over time in non-daily smokers especially among youth, those who smoke less, and those without nicotine dependence. More work on the mental health of non-daily smokers is needed as this is an increasing and understudied group.

IMPLICATIONS

This is the first study to investigate changes in the prevalence of depression among non-daily smokers compared to daily smokers and never-smokers over the past decade in a nationally representative sample of the United States. The results suggest an increase in depression among non-daily smokers over time that did not similarly occur for daily smokers. Further, there were several subgroups of non-daily smokers among whom depression has increased more rapidly. This study suggests the need for more information about the relationship between depression and non-daily smoking including the impact of depression on quit attempts and outcomes.

Interaction between cytochrome P450 2A6 and Catechol-O-Methyltransferase genes and their association with smoking risk in young men

BACKGROUND

Although some effects of gene-gene interactions on nicotine-dopamine metabolism for smoking behavior have been reported, polymorphisms of cytochrome P450 (CYP) 2A6 and catechol-O-methyltransferase (COMT) have not been studied together to determine their effects on smokers. The aim of this study was to investigate the effects of the interaction between the CYP 2A6 and COMT genes on smoking behavior in young Taiwanese men.

RESULTS

A self-report questionnaire regarding smoking status was administered to 500 young men. Polymorphisms of the CYP 2A6 and COMT genes as well as urinary nicotine and urinary cotinine levels were determined. The odds ratio for starting smoking was significantly lower in subjects carrying a CYP2A6 low activity/variant COMT rs4680 genotype than in those possessing a CYP2A6 wild-type/variant COMT rs4680 genotype (0.44, 95% confidence interval = 0.19-0.98, P = 0.043). Comparisons of Fagerstrom Test for Nicotine Dependence (FTND), Physiological Cigarette Dependence Scale (PCDS), and Cigarette Withdrawal symptoms (CWS-21) among the smokers with different CYP2A6/COMT polymorphisms were not significantly different. The adjusted urinary nicotine concentrations were not significantly different between the two groups carrying different genotypes. The adjusted urinary cotinine level was significantly different between the COMT rs4680 wild-type group and COMT rs4680 variant group [92.46 ng/μL vs. 118.24 ng/μL (median value), P = 0.041] and between the COMT rs4680 wild-type/COMT rs165599 variant group and COMT rs4680 variant/COMT rs165599 variant group (97.10 ng/μL vs. 122.18 ng/μL, P = 0.022).

CONCLUSIONS

These findings suggest that a single nucleotide polymorphism (rs4680) of the COMT gene and the interaction between the CYP 2A6 and COMT genes affect smoking status in young Taiwanese men.

A hierarchical causal taxonomy of psychopathology across the life span

We propose a taxonomy of psychopathology based on patterns of shared causal influences identified in a review of multivariate behavior genetic studies that distinguish genetic and environmental influences that are either common to multiple dimensions of psychopathology or unique to each dimension. At the phenotypic level, first-order dimensions are defined by correlations among symptoms; correlations among first-order dimensions similarly define higher-order domains (e.g., internalizing or externalizing psychopathology). We hypothesize that the robust phenotypic correlations among first-order dimensions reflect a hierarchy of increasingly specific etiologic influences. Some nonspecific etiologic factors increase risk for all first-order dimensions of psychopathology to varying degrees through a general factor of psychopathology. Other nonspecific etiologic factors increase risk only for all first-order dimensions within a more specific higher-order domain. Furthermore, each first-order dimension has its own unique causal influences. Genetic and environmental influences common to family members tend to be nonspecific, whereas environmental influences unique to each individual are more dimension-specific. We posit that these causal influences on psychopathology are moderated by sex and developmental processes. This causal taxonomy also provides a novel framework for understanding the heterogeneity of each first-order dimension: Different persons exhibiting similar symptoms may be influenced by different combinations of etiologic influences from each of the 3 levels of the etiologic hierarchy. Furthermore, we relate the proposed causal taxonomy to transdimensional psychobiological processes, which also impact the heterogeneity of each psychopathology dimension. This causal taxonomy implies the need for changes in strategies for studying the etiology, psychobiology, prevention, and treatment of psychopathology. (PsycINFO Database Record

Effects of corticotropin-releasing hormone receptor 1 SNPs on major depressive disorder are influenced by sex and smoking status

BACKGROUND

The corticotropin-releasing hormone receptor 1 (CRHR1) gene has been repeatedly implicated in Major Depressive Disorder (MDD) in humans and animal models; however, the findings are not absolutely convergent. Since recent evidence from genome-wide association studies suggests that narrowing the phenotypic heterogeneity may be crucial in genetic studies of MDD, the aim of this study was to evaluate the effects of CRHR1 polymorphisms on MDD while addressing the influence of sex and smoking status.

METHODS

The association of the CRHR1 SNPs rs12944712, rs110402, and rs878886 with MDD was evaluated in 629 Brazilian adults of European descent recruited from the general population [180 (28.6%) with lifetime MDD]. The sample was subdivided according to sex and smoking status RESULTS: Among nonsmokers, there were nominal associations between MDD and all tested SNPs (rs12944712, P=0.042; rs110402, P=0.031, and rs878886, P=0.040), regardless of sex. In addition, there were significant effects of rs110402 in women (P_corr=0.034) and rs878886 in men (P_corr=0.013). Among lifetime smokers, there were no significant associations between CRHR1 SNPs and MDD LIMITATIONS: The lack of a depression rating scale; scarcity of information on the functionality of the CRHR1 SNPs; and relatively small sample sizes in some subgroups.

CONCLUSIONS

Our results strengthen the evidence for the role of CRHR1 SNPs in MDD susceptibility and suggest that their effects may be modulated by sex and smoking status. These findings suggest the perspective that reducing phenotypic heterogeneity is warranted in genetic studies of MDD.

Individualized Treatment for Tobacco Dependence in Addictions Treatment Settings: The Role of Current Depressive Symptoms on Outcomes at 3 and 6 Months

INTRODUCTION

Individuals with concurrent tobacco dependence and other addictions often report symptoms of low mood and depression and as such may have more difficulty quitting smoking. We hypothesized that current symptoms of depression would be a significant predictor of quit success among a group of smokers receiving individualized treatment for tobacco dependence within addiction treatment settings.

METHODS

Individuals in treatment for other addictions were enrolled in a smoking cessation program involving brief behavioral counseling and individualized dosing of nicotine replacement therapy. The baseline assessment included the Patient Health Questionnaire (PHQ9) for depression. Smoking cessation outcomes were measured at 3 and 6 months post-enrollment. Bivariate associations between cessation outcomes and PHQ9 score were analyzed.

RESULTS

Of the 1,196 subjects enrolled to date, 1,171 (98%) completed the PHQ9. Moderate to severe depression (score >9) was reported by 28% of the sample, and another 29% reported mild depression (score between 5 and 9). Contrary to the extant literature and other findings by our own group, there was no association between current depression and cessation outcome at either 3 months (n = 1,171) (17.0% in those with PHQ9 > 9 vs. 19.8% in those with PHQ9 < 5, p = .32) or 6 months (n = 834) (17.8% vs. 18.9%, p = .74).

CONCLUSIONS

Contrary to our hypothesis, depression severity as measured by the PHQ9 did not predict cessation outcome in this clinical population. A possible explanation may be the individualized treatment and supportive environment of an addictions treatment setting. These data indicate that patients in an addictions treatment setting can successfully quit smoking regardless of current depressive symptoms.

Smoking and the Association Between Depressive Symptoms and Absolute Neutrophil Count in the Investigations Préventives et Cliniques Cohort Study

OBJECTIVES

Depressive symptoms have been associated with chronic low-grade inflammation, including elevated neutrophil count. Smokers often have both high neutrophil count and depressive symptoms. Thus, smoking could explain the cross-sectional association between depressive symptoms and neutrophil count.

METHODS

Total white blood cell count and subtypes, including absolute neutrophil, lymphocyte, monocyte, basophil, and eosinophil counts, were measured in 44,806 participants (28,534 men; mean [standard deviation] age = 38.9 [11.4] years), without a history of chronic disease or current medication. Depressive symptoms were assessed with the Questionnaire of Depression, Second Version, Abridged. Smoking status was self-reported and categorized in five classes. Sex, age, alcohol intake, self-rated health, body mass index, glycemia, physical activity, household composition, occupational status, and education were included as covariates. Associations were examined with general linear models and causal mediation analyses.

RESULTS

After adjustment for all covariates except smoking, depressive symptoms were positively associated with neutrophil count only (β = 5.83, standard error [SE] = 2.41, p = .014). After further adjustment for a semiquantitative measure of smoking, this association was no longer significant (β = 2.40, SE = 2.36, p = .30). Causal mediation analyses revealed that smoking mediated the association (p < .001), accounting for 57% of its total variance. In contrast, depressive symptoms were negatively associated with lymphocyte count in fully adjusted model only (β = -3.21, SE = 1.11, p = .004).

CONCLUSIONS

Smoking may confound or mediate the association between depressive symptoms and neutrophil count. These results advocate for including an accurate measure of smoking in future studies addressing this association. When considering the link between depression and inflammation, one should not overlook the noxious effects of smoking.

Depression status as a predictor of quit success in a real-world effectiveness study of nicotine replacement therapy

To provide population-level evidence of the role of current depression on smoking cessation treatment success, we conducted a secondary analysis of data obtained from a large cessation study conducted in over 13,000 smokers. On the basis of self-reported history of depression diagnoses at baseline, participants were divided into four mutually exclusive groups: current/recent depression, recurrent depression, past depression and no depression history. Cessation outcomes were compared among the four groups at 6-month follow-up. Of the 6261 individuals who were consented and attempted to be contacted for follow-up, 4648 (74.2%) had no diagnostic history of depression, 591 (9.4%) had a past history of depression, 759 (12.1%) had a current/recent depression diagnoses, and 263 (4.2%) had recurrent depression (both current and history). Those with recurrent depression were significantly less likely to quit smoking compared to those with no history of depression. In unadjusted analyses, recurrent depression was associated with significantly lower odds of quitting compared to those with either no history or a past history of depression. Current/recent depression was also associated with poorer quit outcomes compared to those with no history of depression. Depressed smokers may benefit from more individualized, in-person approaches to smoking cessation.

Self-esteem growth trajectory from adolescence to mid-adulthood and its predictors in adolescence

The present study examined the trajectory of self-esteem from adolescence to mid-adulthood and its predictors in adolescence in a prospective cohort sample with a 26-year follow-up. Participants of a Finnish cohort study in 1983 at 16 years (N = 2194) were followed up at ages 22 (N = 1656), 32 (N = 1471) and 42 (N = 1334) years. Self-esteem development was analyzed using latent growth curve models with parental socioeconomic status (SES), parental divorce, school achievement, daily smoking, and heavy drinking as time invariant covariates. Self-esteem grew linearly from 16 to 32 years, but stabilized after that with no growth between 32 and 42 years. Males had significantly higher self-esteem throughout the follow-up, although females had a faster growth rate. Better school performance and higher parental SES were associated with a higher initial level of self-esteem among both genders, while parental divorce among females and daily smoking among males were associated with a lower initial level of self-esteem. Among females the growth rate of self-esteem was practically unaffected by the studied covariates. Among males, however, the initial differences in self-esteem favouring those from a higher SES background were indicated to diminish, while the differences between non-smokers and smokers were indicated to increase. The studied adolescent covariates combined had only limited predictive value for the later self-esteem development. However, the effects of any covariate on the level and slope of the self-esteem trajectory, even if small, should be assessed in combination in order to identify whether they lead to converging, diverging or constantly equidistant self-esteem trajectories. The findings highlight the variety of roles that adolescent behaviours and social environments may have in the developmental process of self-esteem from adolescence into mid-adulthood.

STin2 VNTR polymorphism is associated with comorbid tobacco use and mood disorders

BACKGROUND

There is a significant comorbidity between mood disorders and tobacco use disorder (TUD), which may be related to both genetic and environmental factors. Gene variants of the 5-HT transporter, such as STin2 VNTR (a variable number of tandem repeats in the functional serotonin transporter intron 2) may be associated with mood disorders and TUD.

AIMS

This study aimed to delineate the association between the STin2 genetic polymorphism and comorbid TUD and mood disorders, including depression or bipolar disorder.

METHODS

We examined the STin2 VNTR polymorphism in never-smokers (n=113); patients with mood disorders without TUD (n=62); patients with TUD without mood disorders (n=90); and patients with both disorders (n=95).

RESULTS

We found a significant association between the STin2 genetic polymorphism and the above diagnostic groups whereby the STin2.12 allele shows a positive association with comorbid TUD and mood disorders (Odds ratio=3.07, 95% CI=1.41-6.68), while the STin2.10/10 homozygous genotype shows a negative association (Odds ratio=0.34, 95% CI=0.16-0.74). Adjusting for years of education, age, gender, marital status and ethnicity did not change these results, but showed that TUD was associated with lower education levels and less stable relationships, whereas mood disorders were related to female gender. A family history of TUD was significantly associated with TUD in subjects without mood disorders only.

CONCLUSIONS

The STin2.12 allele is positively and the STin2.10/10 genotype is negatively associated with comorbid TUD and mood disorders, depression or bipolar depression, suggesting that biological endophenotypes, e.g. disorders in serotonin metabolism, may in part underpin this comorbidity.

Smoking history, and not depression, is related to deficits in detection of happy and sad faces

INTRODUCTION

Previous research has demonstrated that chronic cigarette smoking and major depressive disorder (MDD) are each associated with cognitive decrements. Further, these conditions co-occur commonly, though mechanisms in the comorbid condition are poorly understood. There may be distinct, additive, or overlapping factors underlying comorbid cigarette smoking and MDD. The present study investigated the impact of smoking and MDD on executive function and emotion processing.

METHODS

Participants (N=198) were grouped by diagnostic category (MDD and healthy controls, HC) and smoking status (ever-smokers, ES and never-smokers, NS). Participants completed the Facial Emotion Perception Test (FEPT), a measure of emotional processing, and the parametric Go/No-go task (PGNG), a measure of executive function.

RESULTS

FEPT performance was analyzed using ANCOVA with accuracy and reaction time as separate dependent variables. Repeated measures MANCOVA was conducted for PGNG with performance measure and task level as dependent variables. Analyses for each task included diagnostic and smoking group as independent variables, and gender was controlled for. Results for FEPT reveal that lower overall accuracy was found for ES relative to NS, though MDD did not differ from HC. Post-hoc analyses revealed that ES were poorer at identifying happy and sad, but not fearful or angry, faces. For PGNG, poorer performance was observed in MDD relative to HC in response time to Go targets, but there were no differences for ES and NS. Interaction of diagnosis and smoking group was not observed for performance on either task.

CONCLUSIONS

The results of this study provide preliminary evidence for distinctive cognitive decrements in smokers and individuals with depression.

Smoking, alcohol consumption, and drug use among adolescents with psychiatric disorders compared with a population based sample

This study investigated frequencies of smoking, alcohol use, and illicit drug use by diagnostic category in 566 adolescent psychiatric patients, comparing this sample with 8173 adolescents from the general population in Norway who completed the Young-HUNT 3 survey. Frequencies of current alcohol use were high in both samples but were lower among psychiatric patients. Compared with adolescents in the general population, adolescents in the clinical sample had a higher prevalence of current smoking and over four times higher odds of having tried illicit drugs. In the clinical sample, those with mood disorders reported the highest frequencies of smoking, alcohol use, and illicit drug use, whereas those with autism spectrum disorders reported the lowest frequencies. Our results show an increased prevalence of risky health behaviors among adolescents with psychiatric disorders compared with the general population. The awareness of disorder-specific patterns of smoking and substance use may guide preventive measures.

Associations among smoking, anhedonia, and reward learning in depression

Depression and cigarette smoking co-occur at high rates. However, the etiological mechanisms that contribute to this relationship remain unclear. Anhedonia and associated impairments in reward learning are key features of depression, which also have been linked to the onset and maintenance of cigarette smoking. However, few studies have investigated differences in anhedonia and reward learning among depressed smokers and depressed nonsmokers. The goal of this study was to examine putative differences in anhedonia and reward learning in depressed smokers (n=36) and depressed nonsmokers (n=44). To this end, participants completed self-report measures of anhedonia and behavioral activation (BAS reward responsiveness scores) and as well as a probabilistic reward task rooted in signal detection theory, which measures reward learning (Pizzagalli, Jahn, & O'Shea, 2005). When considering self-report measures, depressed smokers reported higher trait anhedonia and reduced BAS reward responsiveness scores compared to depressed nonsmokers. In contrast to self-report measures, nicotine-satiated depressed smokers demonstrated greater acquisition of reward-based learning compared to depressed nonsmokers as indexed by the probabilistic reward task. Findings may point to a potential mechanism underlying the frequent co-occurrence of smoking and depression. These results highlight the importance of continued investigation of the role of anhedonia and reward system functioning in the co-occurrence of depression and nicotine abuse. Results also may support the use of treatments targeting reward learning (e.g., behavioral activation) to enhance smoking cessation among individuals with depression.

Depression and social functioning among HIV-infected and uninfected persons in South Africa

Depression and other health problems are common co-morbidities among persons living with human immunodeficiency virus infection/acquired immunodeficiency syndrome (HIV/AIDS). The aim of this study was to investigate depression, health status, and substance use in relation to HIV-infected and uninfected individuals in South Africa. Using a cross-sectional case-control design, we compared depression, physical health, mental health, problem alcohol use, and tobacco use in a sample of HIV-infected (N = 143) and HIV-uninfected (N = 199) respondents who had known their HIV status for two months. We found that depression was higher, and physical health and mental health were lower in HIV-positive than HIV-negative individuals. Poor physical health also moderated the effect of HIV infection on depression; HIV-positive individuals were significantly more depressed than HIV-negative controls, but only when general physical health was also poor. We did not find an association between alcohol or tobacco use and HIV status. These results suggest the importance of incorporating the management of psychological health in the treatment of HIV.

Bupropion-induced inhibition of α7 nicotinic acetylcholine receptors expressed in heterologous cells and neurons from dorsal raphe nucleus and hippocampus

The pharmacological activity of bupropion was compared between α7 nicotinic acetylcholine receptors expressed in heterologous cells and hippocampal and dorsal raphe nucleus neurons. The inhibitory activity of bupropion was studied on GH3-α7 cells by Ca2+ influx, as well as on neurons from the dorsal raphe nucleus and interneurons from the stratum radiatum of the hippocampal CA1 region by using a whole-cell voltage-clamp technique. In addition, the interaction of bupropion with the α7 nicotinic acetylcholine receptor was determined by [3H]imipramine competition binding assays and molecular docking. The fast component of acetylcholine- and choline-induced currents from both brain regions was inhibited by methyllycaconitine, indicating the participation of α7-containing nicotinic acetylcholine receptors. Choline-induced currents in hippocampal interneurons were partially inhibited by 10 µM bupropion, a concentration that could be reached in the brain during clinical administration. Additionally, both agonist-induced currents were reversibly inhibited by bupropion at concentrations that coincide with its inhibitory potency (IC50=54 µM) and binding affinity (Ki=63 µM) for α7 nicotinic acetylcholine receptors from heterologous cells. The [3H]imipramine competition binding and molecular docking results support a luminal location for the bupropion binding site(s). This study may help to understand the mechanisms of actions of bupropion at neuronal and molecular levels related with its therapeutic actions on depression and for smoking cessation.

SLC6A4 STin2 VNTR genetic polymorphism is associated with tobacco use disorder, but not with successful smoking cessation or smoking characteristics: a case control study

Background

The aim of this study was to determine if variable number of tandem repeats (VNTR) in the second intron (STin2) of the serotonin transporter (SLC6A4) gene was associated with tobacco use disorder, successful smoking cessation, or smoking characteristics. In this case–control study, patients with current tobacco use disorder, diagnosed according to DSM IV criteria (n = 185), and never-smokers, diagnosed according to CDC criteria (n = 175), were recruited and received 52 weeks of combined pharmacotherapy and cognitive therapy. Successful smoking cessation was defined as exhaled carbon monoxide < 6 ppm. SLC6A4 gene STin2 VNTR polymorphism was assessed using a Multiplex-PCR-based method. At baseline, participants were evaluated using the Fagerström Test for Nicotine Dependence (FTND) and the ASSIST scale.

Results

The STin2.12 allele (OR = 2.45; 95% CI = 1.44-4.15, p < 0.001) was associated with an increased risk for tobacco use disorder, while the STin2.10/10 genotype (OR = 0.42; 95% CI 0.25-0.71, p < 0.001) decreased risk. There were no significant associations between tobacco use disorder and the STin2.10 or STin2.9 alleles or the other genotypes (STin2.12/12, 12/10, 12/9, 10/9 or 9/9). There were no significant associations between the STin2 genotypes and alleles and successful smoking cessation, smoking characteristics and increased alcohol or sedative use risk.

Conclusions

Our results suggest that the STin2.10/10 genotype and STin2.12 allele are associated with tobacco use disorder or nicotine dependence, but not with treatment response or severity of dependence. It is hypothesized that the ST2in.12 allele by modulating the metabolism of serotonin may participate in the pathophysiology of tobacco use disorder or nicotine dependence.

The search for peripheral biomarkers for major depression: benefiting from successes in the biology of smoking

The search for robust, clinically useful markers for major depression (MD) has been relatively unproductive. This is unfortunate because MD is one of the largest socio-economic challenges for much of the world and the development of reliable biomarkers for MD could aid in the prevention or treatment of this common syndrome. In this editorial, we compare the approaches taken in the search for biomarkers for MD to that of the more successful searches for biomarkers for tobacco use, and identify several substantive barriers. We suggest that many of the existing clinical repositories used in these biomarkers searches for MD may be of limited value. We conclude that in the future greater attention should be given to the clinical definitions, characterization of confounding environmental factors and age of subjects included in studies. © 2014 Wiley Periodicals, Inc.

Smoking and health-related quality of life in the general population. Independent relationships and large differences according to patterns and quantity of smoking and to gender

Background

Relationships between smoking and health-related quality of life (HRQoL) in the general population remain unclear.

Objectives

To quantify the independent associations between smoking patterns and HRQoL and to identify any threshold or non-linear tendencies in these associations.

Methods

A national representative, cross-sectional household survey of the French general non institutionalized population included 7525 men and 8486 women, aged 25–64 year in 2003. Scores on the eight subscales of the Medical Outcomes Study 36-item Short Form were the primary outcomes. Linear regression analyses were used to evaluate the associations between HRQoL and smoking history, quantity of smoking and smoking cessation while controlling for various socio-economic variables, depression, alcohol dependence and pathological conditions. Analyses were conducted in 2013.

Results

Independent associations between smoking and HRQoL were found, including small positive associations for occasional or light smoking (up to 5 cigarettes per day), and larger and diffuse negative associations above this threshold. Much weaker associations and higher thresholds for negative HRQoL were found for women than for men. For ex-smokers of both genders, HRQoL was found to be better between 2 and 5 years after quitting.

Conclusions

Smoking was independently related to HRQoL, with large differences according to the pattern and quantity of smoking, and to gender. These results may have considerable relevance both for public health action and care of smokers.

Using Mendelian randomisation to infer causality in depression and anxiety research

Depression and anxiety co-occur with substance use and abuse at a high rate. Ascertaining whether substance use plays a causal role in depression and anxiety is difficult or impossible with conventional observational epidemiology. Mendelian randomisation uses genetic variants as a proxy for environmental exposures, such as substance use, which can address problems of reverse causation and residual confounding, providing stronger evidence about causality. Genetic variants can be used instead of directly measuring exposure levels, in order to gain an unbiased estimate of the effect of various exposures on depression and anxiety. The suitability of the genetic variant as a proxy can be ascertained by confirming that there is no relationship between variant and outcome in those who do not use the substance. At present, there are suitable instruments for tobacco use, so we use that as a case study. Proof-of-principle Mendelian randomisation studies using these variants have found evidence for a causal effect of smoking on body mass index. Two studies have investigated tobacco and depression using this method, but neither found strong evidence that smoking causes depression or anxiety; evidence is more consistent with a self-medication hypothesis. Mendelian randomisation represents a technique that can aid understanding of exposures that may or may not be causally related to depression and anxiety. As more suitable instruments emerge (including the use of allelic risk scores rather than individual single nucleotide polymorphisms), the effect of other substances can be investigated. Linkage disequilibrium, pleiotropy, and population stratification, which can distort Mendelian randomisation studies, are also discussed.

Depression and substance abuse and dependency in relation to current smoking status and frequency of smoking among nondaily and daily smokers

BACKGROUND AND OBJECTIVES

Daily smoking rates are decreasing while intermittent or nondaily smoking rates are increasing. Little is known about the association of depression, alcohol abuse and dependence, and illicit drug abuse and dependence with different patterns of smoking, particularly nondaily smoking. Thus, we examined these relationships among current smokers versus nonsmokers and among those who smoke daily versus less frequently.

METHODS

We conducted a secondary analysis of 37,897 adults who participated in the 2008 National Survey on Drug Use and Health. We developed logistic regression models examining predictors of (i) current smoking and (ii) number of days smoking per month (1-10 days, 11-29 days, and ≥30 days) among current smokers, focusing on past-year major depression, alcohol abuse and dependence, and illicit drug abuse and dependence.

RESULTS

Compared to nonsmokers, current smokers more frequently reported a major depressive episode (p < .001), alcohol dependence (p < .001) and abuse (p < .001), and illicit drug dependence (p < .001) and abuse (p < .001), controlling for sociodemographics. Among current smokers, greater smoking frequency was associated with illicit drug dependence (p = .004), but lower likelihood of alcohol dependence (p = .01), alcohol abuse (p = .01), and illicit drug abuse (p = .01).

CONCLUSIONS

Although depression and substance use were associated with greater likelihood of smoking, most measures were inversely associated with frequency of smoking. Thus, it is important to examine underlying mechanisms contributing to these counterintuitive findings in order to inform intervention approaches.

SCIENTIFIC SIGNIFICANCE

With increased rates of nondaily smoking, developing a greater understanding about the mental health correlates related to this pattern of smoking is critical.

Pattern of drug use and depressive symptoms among amphetamine type stimulants users in Beijing and Guangdong province, China

Background

In recent years, amphetamine-type stimulants (ATS) have increased dramatically in East-south Asia, especially in China. Most ATS users suffered from psychosis comorbidity, and depression is the main syndrome in ATS users.

Methodology

A cross-sectional study of depressive symptoms and associated factors among ATS users was conducted in compulsory and voluntary drug detoxification and rehabilitation centers of Beijing and Guangdong Province from March, 2010 to August, 2010. Total 402 eligible participants were recruited and investigated by trained interviewers using a structured questionnaire, the depression was measured by the short 13-item Beck Depression Inventory (BDI-13). Multiple logistic regression was used to determine the impact of associated risk factors of depressive symptoms (%≥8).

Principle Finding

The mean score of BDI-13 is 8.11, and 169 participants (42.04%) have depressive symptoms, including 106 (26.37%) with moderate and 63 (15.67%) with severe depressive symptoms. Higher dose of ATS use, history of ATS relapse were associated with moderate and severe depressive symptoms, the adjusted odds ratios (OR) was 2.62, (95% CI: 1.45–4.74) and 2.01 (95% CI: 1.18–3.42) respectively. The cessation of 12 months or more had less risk of depressive symptoms than the current users, the OR was 0.46 (95% CI: 0.24–0.91), and the ATS users reporting nicotine dependence and alcohol drinking had significantly more risk of depressive symptoms for 3.11 (1.83–5.28) and 2.22 (1.35–3.65) times than those without these behaviors.

Conclusions

Depressive symptoms co-occurred frequently among ATS users in China. The efforts that facilitate drug users’ attempts to stop using ATS use and relapse, quit cigarette smoking and stop alcohol drinking during the ATS treatment and management process should be supported as they may contribute to improving the mental health among this population.

Use of cannabis among 139 cluster headache sufferers

Aims

A case report suggested the efficacy of cannabis to treat cluster headache (CH) attacks. Our aims were to study the frequency of cannabis use in CH patients, and the reported effects on attacks.

Methods

A total of 139 patients with CH attending two French headache centers filled out questionnaires.

Results

Sixty-three of the 139 patients (45.3%) had a history of cannabis use. As compared to nonusers, cannabis users were more likely to be younger ( p < 0.001), male ( p = 0.002) and tobacco smokers ( p < 0.001). Among the 27 patients (19.4% of the total cohort) who had tried cannabis to treat CH attacks, 25.9% reported some efficacy, 51.8% variable or uncertain effects, and 22.3% negative effects.

Conclusions

Cannabis use is very frequent in CH patients, but its efficacy for the treatment of the attacks is limited. Less than one third of self-reported users mention a relief of their attacks following inhalation. Cannabis should not be recommended for CH unless controlled trials with synthetic selective cannabinoids show a more convincing therapeutic benefit.

Neural expression of nicotine's antidepressant properties during tryptophan depletion: an EEG study in healthy volunteers at risk for depression

Nicotine amelioration of serotonergically mediated mood dysregulation may contribute to the comorbidity between cigarette smoking and depression, a disorder which is associated with aberrant activation and hemispheric asymmetry in frontal and posterior cortical regions. This randomized, double-blind study in 20 healthy volunteers with a positive family history of depression examined the effects of transdermal nicotine on mood and EEG changes accompanying transient reductions in serotonin induced by acute tryptophan depletion (ATD). Increased self-ratings of depressed mood and elevation in left frontal high alpha power (decreased activation) were evidenced with ATD (vs. balanced mixture) in participants treated with the placebo but not the nicotine treated group. Nicotine alone increased vigor and posterior high alpha bilaterally, and during ATD it prevented the reduction in left frontal high alpha that was evident in the placebo patch group. These findings indicate that in depression prone individuals, nicotine acts to stabilize the mood lowering and associated frontal functional asymmetry elicited by an acute decrease in brain serotonin.