Changes in genetic and environmental influences on the development of nicotine dependence and major depressive disorder from middle adolescence to early adulthood

Health risk behaviour and persistent and incident depression among middle-aged and older adults in South Africa

The aim of this study was to assess the association between five health risk behaviours and persistent and incident depressive symptoms in a longitudinal study in South Africa. The sample included 5059 men and women (≥40 years) in 2014/2015, and 4176 in 2018/2019 of the 'Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa'. Depressive symptoms were assessed with the Centre for Epidemiologic Studies Depression scale. Multivariable logistic regression analysis was conducted to assess the associations between five health risk behaviours and persistent and incident depressive symptoms. Results indicate that 5.0% of participants had depressive symptoms at both wave 1 and 2 (persistent depressive symptoms), and 27.9% had incident depressive symptoms in wave 2. Higher education and moderate baseline physical activity were negatively associated and those with cardiovascular disease were positively associated with persistent depressive symptoms. Middle wealth index was negative, and being HIV positive and baseline tobacco use were positively associated with incident depressive symptoms. In conclusion, of five health risk behaviours assessed (inadequate fruit/vegetable intake, alcohol dependence, tobacco use, physical activity, and sedentary behaviour), only moderate physical activity was protective against persistent depressive symptoms, and tobacco use was associated with incident depressive symptoms.

Smoke signals: A study of the neurophysiological reaction of smokers and non-smokers to smoking cues inserted into antismoking public service announcements

Tobacco addiction is one of the biggest health emergencies in the world, Antismoking Public Service Announcements (PSAs) represent the main public tool against smoking; however, smoking-related cues (SCs) often included in PSAs can trigger ambiguous cerebral reactions that could impact the persuasiveness and efficacy of the antismoking message. This study aimed to investigate the electroencephalographic (EEG) response in adult smokers and non-smokers during the exposure to SCs presented in antismoking PSAs video, in order to identify eventual neurophysiological features of SCs' 'boomerang effect' elicited in smokers. EEG frontal Alpha asymmetry and frontal Theta were analyzed in 92 adults (30 no smokers, 31 low smokers, 31 high smokers) from EEG recorded during the vision of 3 antismoking PSAs, statistical analysis was conducted using ANOVA. Main results showed a significant interaction between smoking cue condition (Pre and Post) and smoking habit (in particular for female heavy smokers) for the frontal Alpha asymmetry. Since the relative higher right frontal Alpha activity is associated with approach towards a stimulus, it is suggested that the relative left frontal Alpha increase in response to SCs might reflect an appetitive approach in response to it. In the light of the Incentive Sensitization Theory, this pattern can be interpreted as a neurophysiological signal in response to SCs that could undermine the message's effectiveness contributing to the maintenance of the addiction.

Health Conditions, Lifestyle Factors and Depression in Adults in Qingdao, China: A Cross-Sectional Study

Background: Depression is a common mental illness. Previous studies suggested that health conditions and lifestyle factors were associated with depression. However, only few studies have explored the risk factors of depression in a large representative sample of the general population in the world. Methods: A population-based cross-sectional survey was conducted in the 2006 survey and 2009 survey in Qingdao, China. The participants with insufficient information were excluded: Zung score, body mass index (BMI), diabetes items, physical activity, smoking, or drinking. Finally, a total of 3,300 participants were included in this analysis. The category of depression was used in the Zung self-rating depression scale (ZSDS). The associations between different indicators of health conditions (diabetic status, BMI), lifestyle factors (physical activity, smoking, and alcohol consumption), and depression were assessed by the logistic regression model. Results: The mean Zung scores for all participants, male participants, and female participants were 29.73 ± 7.57, 28.89 ± 7.30, 30.30 ± 7.70, respectively. In all participants, those who were pre-diabetes status (OR: 1.53, 95% CI: 1.04-2.27), and irregular physical activity (OR: 0.39, 95% CI: 0.17-0.89) had an increased risk of depression. In man, the analysis showed an increased risk of depression those with pre-diabetes (OR: 2.49, 95% CI: 1.25-4.97), previously diagnosed diabetes (OR: 4.44, 95% CI: 1.58, 12.48), and in those irregular activities (OR: 0.07, 95% CI: 0.01-0.61). In women, those who were underweight (OR: 5.66, 95% CI: 1.04-30.71) had a greater risk of depression. Conclusions: These results suggested that health conditions and lifestyle factors were the potential risk factors for depression. Men with pre-diabetes, previously diagnosed diabetes, and irregular activity had an increased risk for depression; women with underweight status had a higher risk for depression.

Interpersonal childhood adversity and stress generation in adolescence: Moderation by HPA axis multilocus genetic variation

Research suggests that childhood adversity (CA) is associated with a wide range of repercussions, including an increased likelihood of interpersonal stress generation. This may be particularly true following interpersonal childhood adversity (ICA) and for youth with high hypothalamic-pituitary-adrenal (HPA) axis-related genetic risk. In the current study, we applied a multilocus genetic profile score (MGPS) approach to measuring HPA axis-related genetic variation and examined its interaction with ICA to predict interpersonal stress generation in a sample of adolescents aged 14–17 (N = 241, Caucasian subsample n = 192). MGPSs were computed using 10 single nucleotide polymorphisms from HPA axis-related genes (CRHR1, NRC31, NRC32, and FKBP5). ICA significantly predicted greater adolescent interpersonal dependent stress. Additionally, MGPS predicted a stronger association between ICA and interpersonal dependent (but not independent or noninterpersonal dependent) stress. No gene–environment interaction (G×E) effects were found for noninterpersonal CA and MGPS in predicting adolescent interpersonal dependent stress. Effects remained after controlling for current depressive symptoms and following stratification by race. Findings extend existing G×E research on stress generation to HPA axis-related genetic variation and demonstrate effects specific to the interpersonal domain.

Age-Related Differences in the Structure of Genetic and Environmental Contributions to Types of Peer Victimization

The goal of the present investigation was to clarify and compare the structure of genetic and environmental influences on different types (e.g., physical, verbal) of peer victimization experienced by youth in pre-/early adolescence and mid-/late adolescence. Physical, verbal, social, and property-related peer victimization experiences were assessed in two twin samples (306 pairs, ages 9-14 and 294 pairs, ages 15-20). Cholesky decompositions of individual differences in victimization were conducted, and independent pathway (IP) and common pathway (CP) twin models were tested in each sample. In the younger sample, a Cholesky decomposition best described the structure of genetic and environmental contributors to peer victimization, with no evidence that common additive genetic or environmental factors influence different types of peer victimization. In the older sample, common environmental factors influenced peer victimization types via a general latent liability for peer victimization (i.e., a CP model). Whereas the pre-/early adolescent sample demonstrated no evidence of a shared genetic and environmental structure for different types of peer victimization, the mid-/late adolescent sample demonstrates the emergence of an environmentally-driven latent liability for peer victimization across peer victimization types.

The genetic and environmental architecture of substance use development from early adolescence into young adulthood: a longitudinal twin study of comorbidity of alcohol, tobacco and illicit drug use

AIMS

To investigate how use of alcohol, illicit drugs and tobacco come from substance-specific pathways and from pathways general to all three substances through adolescent development.

DESIGN

Analysis of population-based survey. Adolescent twins reported alcohol use (AU), tobacco use (TU) and illicit drug use (IDU) in three waves (2006, 2008, 2010). Restructuring data by age allowed for variance decomposition into age- and substance-specific and common genetic and environmental variance components.

SETTING

Norway.

PARTICIPANTS

Seven national twin birth cohorts from 1988 to 1994, totalling 1483 pairs (558 monozygotic; 925 dizygotic, same and opposite sex).

MEASUREMENTS

Six-point Likert scores of AU, TU and IDU on items from the Monitoring the Future Study.

FINDINGS

Substance use was found to be highly heritable; a²  = 0.73 [95% confidence interval (CI) = 0.61-0.94] for AU, a²  = 0.36 (CI = 0.18-0.52); d²  = 0.49 (95% CI = 0.29-0.62) for IDU and a²  = 0.46 (95% CI = 0.23-0.54); d²  = 0.05 (95% CI = 0.00-0.07) for TU during the whole adolescence period. General substance use (GSU) was also highly heritable at each age and averaged a²  = 0.57 (95% CI = 0.48-0.66). There was a high genetic carry-over from earlier age to later age. Genetic effects on GSU at ages 12-14 years were still detectable 4 years later. New substance (general and specific)-genetic effects also appeared. IDU demonstrated significant non-additive genetic effects (ages 12-14 years). Shared environment had a small impact on AU only. There was almost no non-shared environmental carry-over from age to age, the effect probably due partly to reliability deficiency. Common genetic effects among substance and substance-specific genetic effects were observed at each age-period.

CONCLUSIONS

Among Norwegian adolescents, there appear to be strong genetic effects on both substance-specific and comorbid use of alcohol, illicit drugs and tobacco; individual differences in alcohol use can be explained partially by family background.

The role of unhealthy lifestyles in the incidence and persistence of depression: a longitudinal general population study in four emerging countries

Background

Unhealthy lifestyles and depression are highly interrelated: depression might elicit and exacerbate unhealthy lifestyles and people with unhealthy lifestyles are more likely to become depressed over time. However, few longitudinal evidence of these relationships has been collected in emerging countries. The present study aims i) to analyse whether people with unhealthy lifestyles are more likely to develop depression, and ii) to examine whether depressed people with unhealthy lifestyles are more likely to remain depressed. A total of 7908 participants from Ghana, India, Mexico and Russia were firstly evaluated in the World Health Organization’s Study on Global AGEing and Adult Health (SAGE) Wave 0 (2002–2004) and re-evaluated in 2007–2010 (Wave 1). Data on tobacco use, alcohol drinking and physical activity, were collected. Logistic regressions models were employed to assess whether baseline unhealthy lifestyles were related to depression in Wave 1, among people without 12-month depression in Wave 0 and any previous lifetime diagnosis of depression, and to 12-month depression at both study waves (persistent depression).

Results

Baseline daily and non-daily smoking was associated with depression in Wave 1. Low physical activity and heavy alcohol drinking were associated with persistent depression.

Conclusions

Unhealthy lifestyles and depression are also positively related in emerging countries. Smoking on a daily and non-daily basis was longitudinally related to depression. Depressed people with low physical activity and with heavy drinking patterns were more likely to become depressed over time. Several interpretations of these results are given. Further studies should check whether a reduction of these unhealthy lifestyles leads to lower depression rates and/or to a better clinical prognosis of depressed people.

Association of cytochrome P450 2A6 polymorphism, anxiety, and environmental factors with cigarette smoking by Thai adults

Background

The effects and associations of genetic variation, psychological, and environment factors associated with cigarette smoking and nicotine dependence remain largely unknown.

Objective

To determine the influence and association of functional genetic polymorphisms of cytochrome P450 2A6 (CYP2A6), anxiety, and environmental factors on cigarette smoking and nicotine dependence.

Method

A cross-sectional study was conducted at King Chulalongkorn Memorial Hospital, Thailand between October 2014 and June 2015. We recruited 127 Thai adult smokers when they visited for an annual physical check-up. Participants completed questionnaires regarding demographic characteristics, The Fagerstrom Test for Nicotine Dependence, and The Thai Hospital Anxiety and Depression Scale. Blood was collected for CYP2A6 genotyping to determine the enzyme metabolism level/group.

Results

Factors associated with significantly greater cigarette consumption were age and being ultrarapid/ extensive metabolizers (UM/EM). Anxiety and smoking by household family members were significantly associated with the degree of nicotine dependence. We observed associations between severe nicotine dependence and genotype (UM/EM) and age (b = 0.037; P = 0.005), intermediate metabolizers (IM) and age (b = 0.031; P = 0.43), UM/EM and anxiety (b = 0.258; P < 0.001), IM and anxiety (b = 0.285; P < 0.001), UM/EM and household smoking in the family members (b = 1.427; P = 0.003), and IM and smoking by household family members (b = 1.293; P = 0.024).

Conclusions

Information regarding the association between the gene encoding enzyme metabolism, anxiety, and their interactions may be beneficial for selecting treatment choices for smoking cessation for individual genotypic metabolizers.

The Association of Cigarette Smoking With Depression and Anxiety: A Systematic Review

BACKGROUND

Many studies report a positive association between smoking and mental illness. However, the literature remains mixed regarding the direction of this association. We therefore conducted a systematic review evaluating the association of smoking and depression and/or anxiety in longitudinal studies.

METHODS

Studies were identified by searching PubMed, Scopus, and Web of Science and were included if they: (1) used human participants, (2) were longitudinal, (3) reported primary data, (4) had smoking as an exposure and depression and/or anxiety as an outcome, or (5) had depression and/or anxiety as the exposure and smoking as an outcome.

RESULTS

Outcomes from 148 studies were categorized into: smoking onset, smoking status, smoking heaviness, tobacco dependence, and smoking trajectory. The results for each category varied substantially, with evidence for positive associations in both directions (smoking to later mental health and mental health to later smoking) as well as null findings. Overall, nearly half the studies reported that baseline depression/anxiety was associated with some type of later smoking behavior, while over a third found evidence that a smoking exposure was associated with later depression/anxiety. However, there were few studies directly supporting a bidirectional model of smoking and anxiety, and very few studies reporting null results.

CONCLUSIONS

The literature on the prospective association between smoking and depression and anxiety is inconsistent in terms of the direction of association most strongly supported. This suggests the need for future studies that employ different methodologies, such as Mendelian randomization (MR), which will allow us to draw stronger causal inferences.

IMPLICATIONS

We systematically reviewed longitudinal studies on the association of different aspects of smoking behavior with depression and anxiety. The results varied considerably, with evidence for smoking both associated with subsequent depression and anxiety, and vice versa. Few studies supported a bidirectional relationship, or reported null results, and no clear patterns by gender, ethnicity, clinical status, length to follow-up, or diagnostic test. Suggesting that despite advantages of longitudinal studies, they cannot alone provide strong evidence of causality. Therefore, future studies investigating this association should employ different methods allowing for stronger causal inferences to be made, such as MR.

Aetiological influences on stability and change in emotional and behavioural problems across development: a systematic review

Emotional and behavioural problems in childhood and adolescence can be chronic and are predictive of future psychiatric problems. Understanding what factors drive the development and maintenance of these problems is therefore crucial. Longitudinal behavioural genetic studies using twin, sibling or adoption data can be used to explore the developmental aetiology of stability and change in childhood and adolescent psychopathology. We present a systematic review of longitudinal, behavioural genetic analyses of emotional and behavioural problems between ages 0 to 18 years. We identified 58 studies, of which 19 examined emotional problems, 30 examined behavioural problems, and 9 examined both. In the majority of studies, stability in emotional and behavioural problems was primarily genetically influenced. Stable environmental factors were also widely found, although these typically played a smaller role. Both genetic and environmental factors were involved in change across development. We discuss the findings in the context of the wider developmental literature and make recommendations for future research.

A Review of Impact of Tobacco Use on Patients with Co-occurring Psychiatric Disorders

Consumption of tobacco has been a worldwide problem over the past few decades due to the highly prevalent tobacco-attributable complications. Tobacco use has also been found to be more prevalent in patients with psychiatric disorders. Therefore, we conducted this review about the impact of tobacco use on co-occurring psychiatric disorders. Various facets of this interaction between tobacco use among those with co-occurring psychiatric disorders have been explored. It has been found that people with psychiatric disorders have a higher chance of currently smoking tobacco and lesser chance of cessation. Tobacco use and mental disorders continue to share a complex relationship that has been further evolving after the change in the pattern of tobacco use and also the advent of newer modalities of treatment. However, at the same time, it is believed that cessation of smoking may lead to improvement in the symptoms of mental illness.

Empathy as a "risky strength": a multilevel examination of empathy and risk for internalizing disorders

Learning to respond to others' distress with well-regulated empathy is an important developmental task linked to positive health outcomes and moral achievements. However, this important interpersonal skill set may also confer risk for depression and anxiety when present at extreme levels and in combination with certain individual characteristics or within particular contexts. The purpose of this review is to describe an empirically grounded theoretical rationale for the hypothesis that empathic tendencies can be "risky strengths." We propose a model in which typical development of affective and cognitive empathy can be influenced by complex interplay among intraindividual and interindividual moderators that increase risk for empathic personal distress and excessive interpersonal guilt. These intermediate states in turn precipitate internalizing problems that map onto empirically derived fear/arousal and anhedonia/misery subfactors of internalizing disorders. The intraindividual moderators include a genetically influenced propensity toward physiological hyperarousal, which is proposed to interact with genetic propensity to empathic sensitivity to contribute to neurobiological processes that underlie personal distress responses to others' pain or unhappiness. This empathic personal distress then increases risk for internalizing problems, particularly fear/arousal symptoms. In a similar fashion, interactions between genetic propensities toward negative thinking processes and empathic sensitivity are hypothesized to contribute to excess interpersonal guilt in response to others' distress. This interpersonal guilt then increases the risk for internalizing problems, especially anhedonia/misery symptoms. Interindividual moderators, such as maladaptive parenting or chronic exposure to parents' negative affect, further interact with these genetic liabilities to amplify risk for personal distress and interpersonal guilt as well as for consequent internalizing problems. Age-related increases in the heritability of depression, anxiety, and empathy-related constructs are consistent with developmental shifts toward greater influence of intraindividual moderators throughout childhood and adolescence, with interindividual moderators exerting their greatest influence during early childhood. Efforts to modulate neurobiological and behavioral expressions of genetic dysregulation liabilities and to promote adaptive empathic skills must thus begin early in development.

Gene × smoking interactions on human brain gene expression: finding common mechanisms in adolescents and adults

BACKGROUND

Numerous studies have examined gene × environment interactions (G × E) in cognitive and behavioral domains. However, these studies have been limited in that they have not been able to directly assess differential patterns of gene expression in the human brain. Here, we assessed G × E interactions using two publically available datasets to assess if DNA variation is associated with post-mortem brain gene expression changes based on smoking behavior, a biobehavioral construct that is part of a complex system of genetic and environmental influences.

METHODS

We conducted an expression quantitative trait locus (eQTL) study on two independent human brain gene expression datasets assessing G × E for selected psychiatric genes and smoking status. We employed linear regression to model the significance of the Gene × Smoking interaction term, followed by meta-analysis across datasets.

RESULTS

Overall, we observed that the effect of DNA variation on gene expression is moderated by smoking status. Expression of 16 genes was significantly associated with single nucleotide polymorphisms that demonstrated G × E effects. The strongest finding (p = 1.9 × 10⁻¹¹) was neurexin 3-alpha (NRXN3), a synaptic cell-cell adhesion molecule involved in maintenance of neural connections (such as the maintenance of smoking behavior). Other significant G × E associations include four glutamate genes.

CONCLUSIONS

This is one of the first studies to demonstrate G × E effects within the human brain. In particular, this study implicated NRXN3 in the maintenance of smoking. The effect of smoking on NRXN3 expression and downstream behavior is different based upon SNP genotype, indicating that DNA profiles based on SNPs could be useful in understanding the effects of smoking behaviors. These results suggest that better measurement of psychiatric conditions, and the environment in post-mortem brain studies may yield an important avenue for understanding the biological mechanisms of G × E interactions in psychiatry.

Changes in genetic and environmental influences on trait anxiety ćfrom middle adolescence to early adulthood

BACKGROUND

Middle adolescence to early adulthood is an important developmental period for the emergence of anxiety. Genetically-influenced stable traits are thought to underlie internalizing psychopathology throughout development, but no studies have examined changes in genetic and environmental influences on trait anxiety during this period.

METHOD

A longitudinal twin study design was used to study same-sex twin pairs (485 monozygotic pairs, 271 dizygotic pairs) at three ages, 14, 18, and 21 years, to examine developmental shifts in genetic and environmental effects on trait anxiety.

RESULTS

The heritability of trait anxiety increased with age, particularly between ages 14 and 18, no significant new genetic influences emerged after age 14, and the genetic influences were highly correlated across the three ages, supporting developmentally stable genetic risk factors. The environmental effects shared by members of a family decreased in influence across adolescence, while the influence of environmental effects unique to each individual twin remained relatively stable over the course of development and were largely age-specific.

LIMITATIONS

The twin study design does not inform about specific genes and environmental risk factors.

CONCLUSIONS

Genetic influences increased in importance from middle to late adolescence but common genetic factors influenced trait anxiety across the three ages. Shared environmental influences decreased in importance and demonstrated negligible influence by late adolescence/early adulthood. Nonshared environmental effects were almost entirely age-specific. These findings support the importance of developmentally-sensitive interventions that target shared environmental factors prior to middle adolescence and shifting non-shared environmental risks at each age.

Genetic and environmental influences on affiliation with deviant peers during adolescence and early adulthood

Adolescence and early adulthood is a time when peer groups become increasingly influential in the lives of young people. Youths exposed to deviant peers risk susceptibility to externalizing behaviors and related psychopathology. In addition to environmental correlates of deviant peer affiliation, a growing body of evidence has suggested that affiliation with deviant peers is heritable. This study examined the magnitude of genetic and environmental influences on affiliation with deviant peers, changes in the relative importance of these factors, and which of these factors contribute to the stability of affiliation across this critical developmental period using a longitudinal twin study design that assessed same-sex twins (485 monozygotic pairs, 271 dizygotic pairs) at 3 discrete ages: 15, 18, and 21 years of age. Biometric models revealed that genetic influences increased with age. New genetic influences appeared during late adolescence, and no new genetic influences emerged by age 21. Environmental influences shared by sibling pairs decreased with age, while the proportion of nonshared environmental effects unique to each individual remained relatively stable over the course of development. Shared environmental influences were largely age-overlapping, whereas nonshared environmental influences were largely age-specific. In summary, this study found variance in affiliation with deviant peers is explained by shared and nonshared environment effects as well as by genetic influences (46% by age 21), supporting the role of genetically influenced selection factors. The shared environment was almost exclusively responsible for the stability in late adolescence, while genetic influences were primarily responsible for stability in early adulthood.

Alcohol and tobacco use disorder comorbidity in young adults and the influence of romantic partner environments

BACKGROUND

Although there is considerable evidence that the development of tobacco dependence (TD) and that of alcohol use disorder (AUD) are intertwined, less is known about the comorbid development of these disorders. The present study examines tobacco dependence and alcohol use disorder comorbidity in young adulthood within the context of romantic partner relationships.

METHODS

Data were drawn from the Seattle Social Development Project, a contemporary, ethnically diverse, and gender balanced longitudinal panel including 808 participants. A typological person-centered approach was used to assign participants to four outcome groups: no disorder, tobacco dependence (TD) only, alcohol use disorder (AUD) only, and comorbid (both). Multinomial logistic regression was used to determine the association between partner general and substance-specific environments and single or dual alcohol and tobacco use disorder diagnosis in young adulthood (ages 24-33, n=628). Previous heavy alcohol and tobacco use were controlled for, as were dispositional characteristics, gender, ethnicity, adult SES, and adult depression.

RESULTS

Greater partner conflict increased the likelihood of being comorbid compared to having TD only or AUD only. Having a smoking partner increased the likelihood of being comorbid compared to having AUD only, but having a drinking partner did not significantly distinguish being comorbid from having TD only.

CONCLUSIONS

Findings demonstrated the utility of a comorbidity-based, person-centered approach and the influence of general and tobacco-specific, but not alcohol-specific, partner environments on comorbid alcohol and tobacco use disorders in young adulthood.

Response time variability and response inhibition predict affective problems in adolescent girls, not in boys: the TRAILS study

The present study examines the relationship between neurocognitive functioning and affective problems through adolescence, in a cross-sectional and longitudinal perspective. Baseline response speed, response speed variability, response inhibition, attentional flexibility and working memory were assessed in a cohort of 2,179 adolescents (age 10-12 years) from the TRacking Adolescents' Individual Lives Survey (TRAILS). Affective problems were measured with the DSM-oriented Affective Problems scale of the Youth Self Report at wave 1 (baseline assessment), wave 2 (after 2.5 years) and wave 3 (after 5 years). Cross-sectionally, baseline response speed, response time variability, response inhibition and working memory were associated with baseline affective problems in girls, but not in boys. Longitudinally, enhanced response time variability predicted affective problems after 2.5 and 5 years in girls, but not in boys. Decreased response inhibition predicted affective problems after 5 years follow-up in girls, and again not in boys. The results are discussed in light of recent insights in gender differences in adolescence and state-trait issues in depression.

Comorbid psychiatric disorders and nicotine dependence in adolescence

AIMS

To examine bidirectional influences of onset of psychiatric disorders and nicotine dependence among adolescent smokers.

DESIGN

A prospective longitudinal cohort of adolescents and mothers drawn from a large city school system. Adolescents were interviewed five times and mothers three times over 2 years.

SETTING

Chicago, Illinois.

PARTICIPANTS

Subsample of adolescent smokers (n = 814).

MEASUREMENTS

Selected DSM-IV psychiatric disorders, nicotine dependence and selected risk factors were ascertained.

FINDINGS

Among lifetime smokers, 53.7% experienced at least one nicotine dependence criterion; 26.1% full dependence; 14.1% experienced an anxiety disorder, 18.8% a mood disorder and 29.5% a disruptive disorder. Nicotine dependence and psychiatric disorders were comorbid: nicotine-dependent youths had higher rates of individual and multiple disorders than those not dependent. Controlling for other covariates, mood disorder and nicotine dependence did not predict each other; anxiety disorder predicted nicotine dependence. Bidirectional influences were observed for disruptive disorder and nicotine dependence. Predictors of onset of full nicotine dependence included earlier onset age of tobacco use, high initial pleasant sensitivity to tobacco, alcohol and illicit drug use, abuse and dependence and parental nicotine dependence. Predictors of psychiatric disorder onset included gender, race/ethnicity, other psychiatric disorders, illicit drug abuse or dependence and parental depression and delinquency.

CONCLUSIONS

Initial pleasant experiences of smoking are predictive of later development of nicotine dependence. There may be reciprocal influences between disruptive disorder and development of nicotine dependence in adolescence, and intergenerational transmission of parental nicotine dependence and psychopathology.