Common genetic risk of major depression and nicotine dependence: the contribution of antisocial traits in a United States veteran male twin cohort

Analysis of patient health questionnaire-9 (PHQ-9) based depression prevalence according to a discordance between quantitative urinary cotinine levels and self-report of second-hand smoke exposure among adults: A cross-sectional study

Background

Second-hand smoke (SHS) exposure appears to be more common among individuals with depression. However, self-report of SHS exposure is an inaccurate classification compared to confirming SHS exposure using urinary cotinine (UC). Additionally, the dose-response relationship between depression and UC is controversial.

Methods

The severe stress rate and depression prevalence was estimated among 14530 Korean participants aged ≥19 years using data patient health questionnaire-9 (PHQ-9) and on UC from the Korean National Health and Nutrition Examination Survey. Measured UCs were divided into four categories: UC- (≤0.3 μg/L), UC± (0.4 μg/L-0.9 μg/L), UC+ (1.0 μg/L-11.9 μg/L), and UC++ (≥12.0 μg/L).

Results

About 55.0 % participants were female and participants' mean age was 51.1 years. Non-smokers were 80.3 %. Among non-smokers, non-SHS exposure participants (SR-) and SHS exposure participants (SR+) were 83.0 % and 17.0 %, respectively. When UC- was used as the reference subgroup, the UC++ subgroup showed a higher depression prevalence, whereas the UC ± subgroup showed a lower prevalence. In the same UC categories, the depression prevalence and severe stress rate were higher among females than among males. Furthermore, the SR + subgroup had a higher severe stress rate than the SR- subgroup.

Conclusions

Our study showed a paradoxical reduction in the depression prevalence and severe stress rate in the UC ± subgroup compared to the UC- subgroup. Additionally, the dose-response relationship between the SHS exposure biomarker and the depression prevalence was not linear. Our study indicates that an emotional stress-based model may be more appropriate for explaining the relationship between depression and SHS exposure.

Substance Use in U.S. Vietnam War Era Veterans and Nonveterans: Results from the Vietnam Era Health Retrospective Observational Study

Background: Substance use (SU) is associated with physical injury and mental health disorders in older persons, but recent research has scarcely examined SU in U.S. Vietnam-era veterans who are mostly in or near their eighth decade of life. Objectives: We compared the prevalence of self-reported lifetime and current SU and modeled current usage patterns in a nationally representative sample of veterans versus a matched nonveteran cohort. Methods: Cross-sectional, self-reported survey data were analyzed from the 2016-2017 Vietnam Era Health Retrospective Observational Study (VE-HEROeS) (n = 18,866 veterans, n = 4,530 nonveterans). We assessed lifetime and current alcohol and drug use disorders; lifetime and current use of cannabis, opioids, stimulants, sedatives, "other drugs" (psychedelics, prescription or over-the-counter drugs not prescribed/used as intended); and current SU patterns (alcohol-use-only, drug-use-only, dual-SU, no SU). Weighted descriptive, bivariable, and multivariable statistics were calculated. Covariates in multinomial modeling included sociodemographic characteristics, lifetime cigarette smoking, depression, potentially traumatic events (PTEs), and current pain (SF-8^TM). Results: Prevalence of lifetime opioid and sedative use (p ≤ .01), drug and alcohol use disorders (p < .001), and current "other drug" use (p < .001) were higher in veterans versus nonveterans. Current use of alcohol and cannabis was high in both cohorts. In veterans, very severe/severe pain, depression, and PTEs were highly associated with drug-use-only (p < .001) and dual-SU (p < .01), but these associations were fewer for nonveterans. Conclusion: This research confirmed existing concerns over substance misuse in older individuals. Vietnam-era veterans may be at particular risk due to service-related experiences and later-life tribulations. Era veterans' unique perceptions toward healthcare assistance for SU may need greater provider focus to maximize self-efficacy and treatment.

Internalizing and externalizing psychopathology in middle age: genetic and environmental architecture and stability of symptoms over 15 to 20 years

BACKGROUND

Internalizing and externalizing psychopathology factors explain much of the covariance among psychiatric conditions, especially at the level of genetic risk. However, few studies have examined internalizing and externalizing factors in middle-aged samples, especially their ability to predict later symptoms across midlife. The goals of the current study were (i) to quantify the genetic and environmental influences on internalizing and externalizing psychopathology in individuals in their early 40s, and (ii) examine the extent to which these genetic and environmental influences predict self-reported measures of internalizing and externalizing symptoms 15-20 years later.

METHOD

1484 male twins completed diagnostic interviews of psychopathology at mean age 41 and self-reported measures of anxiety, depression, substance use, and related variables at up to two time-points in late middle age (mean ages 56 and 62).

RESULTS

Structural equation modeling of the diagnostic interviews confirmed that internalizing and externalizing factors accounted for most of the genetic variance in individual disorders, with substantial genetic (ra = 0.70) and environmental (re = 0.77) correlations between the factors. Internalizing psychopathology at age 41 was correlated with latent factors capturing anxiety, depression, and/or post-traumatic stress symptoms at ages 56 (r = 0.51) and 62 (r = 0.43). Externalizing psychopathology at age 41 was correlated r = 0.67 with a latent factor capturing aggression, tobacco use, and alcohol use at age 56. Stability of both factors was driven by genetic influences.

CONCLUSIONS

These findings demonstrate the considerable stability of internalizing and externalizing psychopathology symptoms across middle age, especially their genetic influences. Diagnostic interviews effectively predict self-reported symptoms and behaviors 15-20 years later.

Work Stress and Depressive Symptoms in Fishermen With a Smoking Habit: A Mediator Role of Nicotine Dependence and Possible Moderator Role of Expressive Suppression and Cognitive Reappraisal

This study examined pathways of influence between work stress, depressive symptoms, nicotine dependence, expressive suppression, and cognitive reappraisal in fishermen with smoking habits in Qionghai, Hainan province, China (N = 1068). These fishermen responded to multiple assessments a week before leaving on a deep-sea fishing trip, including a Mental Stressor Investigation Questionnaire (MSIQ), the Center for Epidemiological Studies Depression Scale (CES-D), the Russell Reason for Smoking Questionnaire (RRSQ), and an Emotion Regulation Questionnaire (ERQ). Structural equation modeling (SEM) analyses of the collected data in Mplus 7 showed that work stress and nicotine dependence were independent predictors of depressive symptoms. The relationship between work stress and depressive symptoms was found to be partially mediated by nicotine dependence and be moderated by cognitive reappraisal. The evidence suggests it advantageous to examine the need of work stress, nicotine dependence, and cognitive reappraisal when attempting to understand depressive symptoms in fishermen with a smoking habit. These findings suggest that improving nicotine dependence through work stress management and training in cognitive reappraisal could be utilized as effective modalities for improving depressive symptoms.

Gene-Environment Interactions Between Depressive Symptoms and Smoking Quantity

We investigated genetic and environmental correlations and gene by environment interactions (GxE) between depressive symptoms measured by the Beck Depression Inventory (BDI) and quantity smoked measured by number of cigarettes smoked per day (CPD) using quantitative genetic modeling. The population-based sample consisted of 12,063 twin individuals from the Finnish Twin Cohort Study. Bivariate Cholesky decomposition revealed that the phenotypic correlation (r = 0.09) between BDI and CPD was explained by shared genetic (r g = 0.18) and environmental (r e = 0.08) factors. GxE models incorporating moderator effects were built by using CPD as trait and BDI as moderator and vice versa. The importance of the genetic variance component increased with increasing moderator value in both models. Thus, the influence of genetic effects on variance of smoking quantity was enhanced in individuals with elevated depression score and vice versa; the genetic effects on depression variance were potentiated among heavy smokers. In conclusion, shared genetic and environmental factors as well as GxE underlie the association of smoking with depression.

Dhat syndrome: evidence for a depressive spectrum subtype

INTRODUCTION

Dhat syndrome is a condition described in the Indian subcontinent, in which patients present with concerns about loss of semen. Though this condition has been conceptualized as a culture-bound syndrome, some authors have also considered it a manifestation of depression. This calls for a closer examination of the possible genetic link between Dhat syndrome and depression.

METHOD

We examined the relationship between Dhat syndrome and the depressive spectrum, as conceptualized by Winokur, using a retrospective design. The case records of 46 patients with Dhat syndrome were reviewed, and patients were divided into two groups - family history positive (FH+) and family history negative (FH-) - based on the presence of depressive spectrum conditions in first degree relatives. These two groups were compared in terms of demographic variables, symptom profile and comorbidity.

RESULTS

The FH+ group had significantly higher rates of depressive disorders and substance use disorders (alcohol and nicotine dependence). They were also more likely to report concerns about penile size.

DISCUSSION

These results suggest that a subgroup of patients with the Dhat syndrome can be viewed as suffering from a depressive spectrum disorder. Dhat syndrome may be better understood as a heterogeneous group than as a single diagnostic entity. Identifying such sub-groups can help in choosing optimal treatments for patients with Dhat syndrome, such as selecting antidepressants for the group described in this study.

Parent, sibling and peer associations with subtypes of psychiatric and substance use disorder comorbidity in offspring

BACKGROUND

Parental substance use disorder (SUD) is associated with a range of negative offspring outcomes and psychopathology, but the clustering of these outcomes into subtypes has seldom been examined, nor have the familial and environmental contexts of these subtypes been reported. The present study examines the clustering of offspring lifetime substance use and psychiatric disorders into subtypes and characterizes them in terms of familial and non-familial influences using an offspring-of-twins design.

METHOD

Telephone-administered diagnostic interviews were used to collect data on psychiatric disorders and SUD from 488 twin fathers, 420 biological mothers and 831 offspring. Latent class analysis (LCA) was used to derive subtypes of lifetime comorbidity in offspring. Familial risk and environmental variables associated with each subtype (i.e., parenting, childhood physical or sexual abuse, perceived sibling and peer substance use) were identified using multinomial logistic regression.

RESULTS

Four classes identified by LCA were characterized as (1) unaffected, (2) alcohol abuse/dependence, (3) alcohol abuse/dependence comorbid with anxiety and depression, and (4) alcohol, cannabis abuse/dependence and nicotine dependence comorbid with conduct disorder. Inconsistent parenting, childhood physical/sexual abuse, and perceived sibling and peer substance use were significantly associated with profiles of offspring comorbidity after adjusting for familial vulnerability. Some associations were specific (i.e., perceived peer alcohol use to the AUD class), while others were general (peer smoking to all 3 comorbidity classes).

CONCLUSIONS

We observed distinct subtypes of psychiatric and SUD comorbidity in adolescents and young adults. Subtypes of offspring psychopathology have varied associations with parental psychopathology, family environment, and sibling and peer behaviors.

The relationship between personality disorders and Axis I psychopathology: deconstructing comorbidity

The purpose of this review is (a) to study and systematically review the recent literature examining the co-occurrence and relationships between Axis I psychiatric disorders and Axis II personality disorders, specifically the six originally proposed for the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5, and (b) to consider the clinical utility of the current Axis I and Axis II approach in the DSM-IV-TR and apply findings to state a position on the issue of collapsing together Axis I and Axis II. Community surveys or prospective cohort studies were reviewed as a priority. Our review indicates that the associations between clinical disorders and personality disorders clearly varied within each disorder and across the six personality disorders. Our understanding has advanced, particularly related to the clinical utility of comorbidity, and there may be sufficient evidence to support moving borderline personality disorder to Axis I. However, it seems premature to conclude that comorbidity is best conceptualized by having all disorders in a single category or by deleting disorders so that comorbidity is reduced. Our review suggests some priorities for future research into comorbidity, such as including personality disorders in future multivariate comorbidity models.

Nicotine dependence and comorbid psychiatric disorders: examination of specific genetic variants in the CHRNA5-A3-B4 nicotinic receptor genes

BACKGROUND

The associations between nicotine dependence and specific variants in the nicotinic receptor CHRNA5-A3-B4 subunit genes are irrefutable with replications in many studies. The relationship between the newly identified genetic risk variants for nicotine dependence and comorbid psychiatric disorders is unclear. We examined whether these genetic variants were associated with comorbid disorders and whether comorbid psychiatric disorders modified the genetic risk of nicotine dependence.

METHODS

In a case control study of nicotine dependence with 2032 subjects of European descent, we used logistic regression models to examine the pleiotropy and risk moderation. Comorbid disorders examined were alcohol dependence, cannabis dependence, major depressive disorder, panic attack, social phobia, posttraumatic stress disorder (PTSD), attention deficit hyperactivity disorder (ADHD), conduct disorder, and antisocial personality disorder (ASPD).

RESULTS

Nicotine dependence was associated with every examined comorbid psychiatric disorders, with odds ratio varying from 1.75 to 3.33. No evidence supported the associations between the genetic variants and the comorbid disorders (pleiotropy). No evidence suggested that the risks for nicotine dependence associated with the genetic variants vary with comorbid psychiatric disorders in general, but the power was limited in detecting interactions.

CONCLUSIONS

The genetic risks of nicotine dependence associated with the CHRNA5-A3-B4 subunit genes are specific, and not shared among commonly comorbid psychiatric disorders. The risks for nicotine dependence associated with these genetic variants are not modified by comorbid psychiatric disorders such as major depressive disorder or alcohol dependence. However, the power is an important limitation in studying the interplay of comorbidity and genetic variants.

Contribution of parental psychopathology to offspring smoking and nicotine dependence in a genetically informative design

OBJECTIVE

It is not known if parental psychiatric disorders have an independent effect on offspring smoking after controlling for genetic and environmental vulnerability to nicotine dependence. We tested if parental alcohol, drug, or conduct disorders; antisocial personality disorder; depression; and anxiety disorders remained significant predictors of offspring smoking initiation, regular smoking, and nicotine dependence before and after adjusting for genetic and environmental risk for nicotine dependence.

METHOD

Data were obtained via semi-structured interviews with 1,107 twin fathers, 1,919 offspring between the ages of 12 and 32, and 1,023 mothers. Genetic and environmental liability for smoking outcomes was defined by paternal and maternal nicotine dependence. Multinomial logistic regression models were computed to estimate the risk for offspring trying cigarettes, regular smoking, and the Fagerström Test for Nicotine Dependence (FTND) as a function of parental psychopathology and sociodemographics before and after adjusting for genetic and environmental vulnerability to nicotine dependence.

RESULTS

Before adjusting for genetic and environmental risk for nicotine dependence, ever trying cigarettes was associated with maternal depression, regular smoking was associated with maternal alcohol dependence and maternal conduct disorder, and FTND was associated with paternal and maternal conduct disorder and antisocial personality disorder. No parental psychopathology remained significantly associated with regular smoking and FTND after adjusting for genetic and environmental vulnerability to nicotine dependence in a multivariate model.

CONCLUSIONS

The association between parental psychopathology and offspring smoking outcomes is partly explained by genetic and environmental risk for nicotine dependence. Point estimates suggest a trend for an association between parental antisocial personality disorder and offspring regular smoking and nicotine dependence after adjusting for genetic and environmental vulnerability. Studies in larger samples are warranted.

Genetic and environmental influences on psychiatric comorbidity: a systematic review

BACKGROUND

The purpose of this review is to systematically appraise the peer-reviewed literature about the genetic and environmental determinants of psychiatric comorbidity, focusing on four of the most prevalent types of psychopathology: anxiety disorders, depression, conduct disorder and substance abuse.

METHODS

We summarize existing empirical research on the relative contribution that genetic, nonshared and shared environmental factors make to the covariance between disorders, and evidence about specific genes and environmental characteristics that are associated with comorbidity.

RESULTS

Ninety-four articles met the inclusion criteria and were assessed. Genetic factors play a particularly strong role in comorbidity between major depression and generalized anxiety disorder or posttraumatic stress disorder, while the non-shared environments make an important contribution to comorbidity in affective disorders. Genetic and non-shared environmental factors also make a moderate-to-strong contribution to the relationship between CD and SA. A range of candidate genes, such as 5HTTLPR, MAOA, and DRD1-DRD4, as well as others implicated in the central nervous system, has been implicated in psychiatric comorbidity. Pivotal social factors include childhood adversity/life events, family and peer social connections, and socioeconomic and academic difficulties.

LIMITATIONS

Methodological concerns include the use of clinical case-control samples, the focus on a restricted set of individual-level environmental risk factors, and restricted follow-up times.

CONCLUSIONS

Given the significant mental health burden associated with comorbid disorders, population-based research on modifiable risk factors for psychiatric comorbidity is vital for the design of effective preventive and clinical interventions.

Effects of nicotine on depressive-like behavior and hippocampal volume of female WKY rats

The observed high incidence of smoking amongst depressed individuals has led to the hypothesis of 'self medication" with nicotine in some of these patients. The inbred Wistar-Kyoto (WKY) rats exhibit depressive-like characteristics as evidenced by exaggerated immobility in the forced swim test (FST). One aim of this study was to investigate whether nicotine may have an antidepressant-like effect in these animals. Moreover, because of human postmortem studies indicating a reduction of the hippocampus volume in depressed patients, it was of interest to determine whether such an anatomical anomaly may also be manifested in WKY rats and whether it would be affected by chronic nicotine treatment. Adult female WKY and their control Wistar rats were administered nicotine consecutively (0.2 mg/kg, i.p., once or twice daily for 14 days) and their activity in an open field, as well as their immobility in FST were assessed either 15 min or 18 h after the last injection. Another set of animals was treated twice daily with 0.2 mg/kg nicotine for 14 days and sacrificed on day 15 for stereological evaluation of the hippocampal volume. When tested 15 min after the last injection, once or twice daily nicotine exacerbated the immobility in the FST in WKY rats only. When tested 18 h after the last injection, only twice daily nicotine treatment resulted in less immobility in the FST in WKY rats. Open field locomotor activity was not affected by any nicotine regimen. WKY rats had significantly less hippocampal volume (approximately 20%) than Wistar rats which was not altered by nicotine. These findings further validate the use of WKY rats as an animal model of human depression and signify the importance of inherent genetic differences in final behavioral outcome of nicotine.

Smoking, nicotine and neuropsychiatric disorders

Tobacco smoking is an extremely addictive and harmful form of nicotine (NIC) consumption, but unfortunately also the most prevalent. Although disproportionately high frequencies of smoking and its health consequences among psychiatric patients are widely known, the neurobiological background of this epidemiological association is still obscure. The diverse neuroactive effects of NIC and some other major tobacco smoke constituents in the central nervous system may underlie this association. This present paper summarizes the pharmacology of NIC and its receptors (nAChR) based on a systematic review of the literature. The role of the brain's reward system(s) in NIC addiction and the results of functional and structural neuroimaging studies on smoking-related states and behaviors (i.e. dependence, craving, withdrawal) are also discussed. In addition, the epidemiological, neurobiological, and genetic aspects of smoking in several specific neuropsychiatric disorders are reviewed and the clinical relevance of smoking in these disease states addressed.

Do the same genetic and environmental effects underlie the covariation of alcohol dependence, smoking, and aggressive behaviour?

We investigated genetic and environmental effects on alcohol dependence, smoking, and aggressive behaviour, as well as sex differences in these effects and whether these effects were the same for the three phenotypes. There were 3141 male (mean age 26.2 [S.E.=0.1]) and 6026 female (mean age 26.1 [S.E.=0.1]) participants in this extended twin study. Alcohol Use Disorder Identification Test (AUDIT), number of cigarettes smoked, and two subscales of Aggression Questionnaire (AQ) were used to assess the phenotypes. All three were positively interrelated with males exhibiting higher levels on each phenotype. Multivariate model fitting identified genetic effects on all phenotypes for both men and women ranging between 69% (aggressive behaviour in women) and 78% (alcohol dependence in men). The effects were stronger in men for alcohol dependence and smoking. There were no qualitative genetic sex differences. Genetic correlations between all phenotypes were substantial.