Adolescent alcohol use is predicted by childhood temperament factors before age 5, with mediation through personality and peers

Drinking Motives, Alcohol Misuse, and Internalizing and Externalizing Psychopathology across College: A Cross-Lagged Panel Study

Background: Drinking motives are strong proximal predictors of alcohol use behaviors and may represent a mediational mechanism by which different individual predispositions toward internalizing or externalizing psychopathology lead to the development of alcohol misuse. However, whether the association is due to a causal relationship or a shared etiology (i.e., confounding) is difficult to determine and may change across developmental periods. Methods: This study leveraged a cross-lagged panel design to disentangle the nature of the relationships between self-report measures of drinking motives, alcohol misuse, and internalizing and externalizing psychopathology in a 4-year longitudinal sample of college students (N = 9,889). Results: Results pointed to a putative causal effect of drinking motives on early binge drinking frequency, but the direction of effect later reversed, reflecting a possible developmental shift during college. On the other hand, the relationships between drinking motives and internalizing/externalizing psychopathology appeared to be driven by shared etiology rather than direct causal mechanisms. Conclusions: These findings highlight the distinct and important role of drinking motives in the etiology of alcohol misuse and have implications for the application of tailored prevention and treatment strategies.

Externalizing Risk Pathways for Adolescent Substance Use and Its Developmental Onset: A Canadian Birth Cohort Study: Trajectoires de comportements extériorisés et le risque pour l'initiation et l'usage de substances des adolescents : Une étude de cohorte de naissance canadienne

OBJECTIVE

Only a minority of drug and alcohol users develops a substance use disorder. Previous studies suggest that this differential vulnerability commonly reflects a developmental trajectory characterized by diverse externalizing behaviors. In this study, we examined the relation between child and adolescent externalizing behaviors and adolescent substance use in a prospectively followed Canadian birth cohort, accounting for the temporal sequence of a wide variety of contributing factors.

METHODS

Two hundred and forty-two adolescents followed since birth (date range: 1996 to 2012) were assessed on externalizing behavior (age 17 months to 16 years), alcohol and cannabis use at age 16, age of alcohol use onset, family history of substance use problems, family functioning (age 11 to 15), sensation seeking (age 16), prenatal substance exposure, socioeconomic status (age 1 to 9), and sex.

RESULTS

Age of alcohol use onset was predicted by a family history of substance use problems, externalizing traits from ages 6 to 10 and 11 to 16, sensation seeking at age 16, prenatal alcohol and tobacco exposure and family functioning at ages 11 to 15. High frequencies of alcohol and cannabis use at age 16 were both predicted by externalizing traits from ages 11 to 16, a family history of substance use problems and sensation seeking after controlling for other individual, environmental and familial variables. The association between familial substance use problems and substance use during adolescence was partially mediated by externalizing traits from age 11 to 16.

CONCLUSIONS

The present findings provide prospective evidence for a developmental risk pathway for adolescent substance use, potentially identifying those who could benefit from early interventions.

Neurobiological mechanisms of early life adversity, blunted stress reactivity and risk for addiction

Blunted stress reactivity resulting from early exposure to stress during childhood and adolescence may increase vulnerability to addiction. Early life adversity (ELA) affects brain structure and function and results in blunted stress axis reactivity. In this review, we focus on the underlying neurobiological mechanisms associated with a blunted response to stress, ELA, and risk for addictive disorders. ELA and blunted reactivity are accompanied by unstable mood regulation, impulsive behaviors, and reduced cognitive function. Neuroimaging studies reveal cortical and subcortical changes in persons exposed to ELA and those who have a genetic disposition for addiction. We propose a model in which blunted stress reactivity may be a marker of risk for addiction through an altered motivational and behavioral reactivity to stress that contribute to disinhibited behavioral reactivity and impulsivity leading in turn to increased vulnerability for substance use. Evidence supporting this hypothesis in the context of substance use initiation, maintenance, and risk for relapse is presented. The effects of ELA on persons at risk for addiction may lead to early experimentation with drugs of abuse. Early adoption of drug intake may alter neuroregulation in such vulnerable persons leading to a permanent dysregulation of motivational responses consistent with dependence. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Predictive validity of genome-wide polygenic scores for alcohol use from adolescence to young adulthood

BACKGROUND

Adolescence is a critical period for experimenting with alcohol, and these early experiences have long-term influences on alcohol-related behaviours throughout adulthood. This study examined the utility of genome-wide polygenic scores (GPS) for predicting alcohol use during adolescence and young adulthood.

METHODS

We used GPS based on the Genome-wide association study and Sequencing Consortium of Alcohol and Nicotine use (GSCAN) study on drinks per week to predict alcohol use in a longitudinal, UK-representative sample of unrelated adolescents aged 16 through to 22 years (N_max = 3390).

RESULTS

At age 16, the GSCAN GPS predicted variance in alcohol consumption on a typical day (0.58 %), intake frequency (0.89 %), and hazardous drinking (i.e. ≥6 units at one occasion) (1.07 %). At age 22, the predictive power of the GPS had increased, explaining variance in alcohol consumption (0.61 %), intake frequency (1.69 %), and hazardous drinking (1.19 %).

CONCLUSIONS

The predictive validity of GPS for phenotypic alcohol use was evident in adolescence and increased in young adulthood. The findings suggest that GPS, which are available from birth, may be potentially useful for identifying individuals at risk for harmful and hazardous alcohol use. However, because the overall effect sizes were small, the utility of the GPS that are currently available is limited for the prediction of individual-level alcohol use.

Risks versus consequences of adolescent and young adult substance use: A focus on executive control

PURPOSE OF REVIEW

This review examines the role of executive control processes in the liability for substance misuse and whether substance use, once initiated, leads to subsequent decrements as proposed by neurotoxicity models of substance use disorder (SUD).

RECENT FINDINGS

As indicated by a number of recent meta-analyses, executive control processes, which include working memory, cognitive flexibility and numerous aspects of attentional, behavioral and emotional control, are impaired in the context of active SUD. Longitudinal studies of behaviorally disinhibited children, individuals with familial risks for SUD, and twins within whom genetic versus environmental influences on behavior can be modeled robustly indicate that relatively poor control is a vulnerability factor for early substance use initiation, binge patterns of use, and subsequent SUD. Evidence of further declines in executive control, once substance use is initiated, is mixed, although a growing number of neuroimaging studies indicate that frontostriatal, frontolimbic, and frontocerebellar systems are altered as a consequence of use.

SUMMARY

Together these patterns suggest strategies for identifying children and adolescents at high risk for SUD, avenues through which substance-related neurotoxicities can be more reliably detected, and the need to structure prevention efforts in a manner that is developmentally appropriate and perhaps personalized to individual vulnerabilities.

Early life temperamental anxiety is associated with excessive alcohol intake in adolescence: A rhesus monkey (Macaca mulatta) model

Teenage alcohol abuse is a major health concern, particularly because the majority of alcohol consumed by teenagers is via binge drinking, a known risk factor for increasing the likelihood for the development of future alcohol use disorders (AUDs). Identifying individuals at risk for excessive alcohol intake in adolescence is a step toward developing effective preventative measures and intervention programs. As adults with AUDs tend to self-medicate their anxiety with alcohol, this longitudinal study assesses the role of infant anxiety-like temperament in the development of adolescent alcohol abuse using a nonhuman primate model. From birth until they were 5 months of age, behaviors of 64 rhesus monkeys (Macaca mulatta) were coded twice a week using an objective mother-infant scoring system that included behaviors traditionally used to assess anxiety and fearfulness in rhesus monkeys. When subjects were four months old, plasma cortisol was obtained. When subjects were adolescents (M_age = 44.88 months), another plasma cortisol sample was obtained about one month prior to allowing them unfettered access to an 8.4% (v/v) aspartame-sweetened alcohol solution for one hour a day over five-to-seven weeks. Results showed that behavioral indications of anxiety-like temperament in infancy, including high levels of mother-infant mutual ventral contact, low levels of environmental exploration, and low levels of interactions with peers were predictive of high adolescent alcohol intake (ie, drinking to intoxication). Plasma cortisol levels in infancy were positively correlated with plasma cortisol in adolescence, and both were positively correlated with high adolescent alcohol intake. Our findings indicate that high levels of traditional anxiety-like behaviors measured in the context of mother-infant interactions, coupled with high infant and adolescent plasma cortisol, are associated with binge-like high alcohol intake in adolescence, suggesting that individuals at risk for developing an AUD later in life may be determined, at least in part, by assessing their physiological and behavioral propensity for anxiety early in life.

Neonatal temperament and neuromotor differences are predictive of adolescent alcohol intake in rhesus monkeys (Macaca mulatta)

Identifying predictors of teenage alcohol use disorder (AUDs) is a major health initiative, with studies suggesting that there are distinct personality-related traits that underlie patterns of alcohol intake. As temperament is biologically based, identifiable early in life, and stable across time, it is considered the foundation of personality. As such, we hypothesized that neonatal temperament traits would predict anxiety-mediated adolescent alcohol consumption. To test this, N = 145 rhesus macaque (Macaca mulatta) infants (14 days of age), reared in a neonatal nursery (n = 82) or in a control condition with their mothers (n = 63) were assessed with a widely used standardized nonhuman primate testing battery, the Infant Behavioral Assessment Scale (IBAS), modeled after the Brazelton Neonatal Assessment Scale, evaluating visual orienting, temperament, motor maturity and, more recently, sensory sensitivity. As adolescents (3-4 years of age), these same subjects were allowed unfettered access to a sweetened-alcohol solution for 1 hr/day, 4 days/week, over 5-7 weeks. Subjects were allowed to self-administer alcohol while housed alone (n = 70) or socially in their home cage (n = 55). Linear regressions showed that alcohol intake was predicted by neonatal orienting ability (β = -.35; p = .01), state control (β = -.19; p = .04), and motor maturity (β = -.24; p = .01). Poor neonatal orienting, state control (ease of consolability), and motor maturity were associated with higher adolescent alcohol intake in rhesus monkeys. These findings suggest that neonatal temperament is predictive of patterns of adolescent alcohol intake. To the extent that these results generalize to humans, they provide evidence that early-life temperament and neurodevelopment may be important risk factors for adolescent AUDs and that the IBAS may be used as an assessment tool for identifying such risk.

Parent-reported childhood temperament and adolescent self-reported substance use initiation

Children differ in their general temperament and these differences predict consequential outcomes, including mental health, peer relations, and academic performance. In adults, there is strong evidence that personality correlates with substance use, but the temporal direction of the relation is unclear, as substance use may alter personality. The present research uses data from the Longitudinal Study of Australian Children (N = 5,362) to examine whether temperament assessed by parents in early childhood is associated with adolescent self-reported initiation of alcohol, cigarette, marijuana, or other drug use. Children rated higher on sociability at 4-5 years old were at higher risk of initiation for all types of substances in adolescence (age 12 to 17), controlling for SES, single-parent household, parent substance use, and other demographic variables. Additionally, children rated higher on reactivity were at higher risk of cigarette or marijuana use initiation, and children rated higher on persistence had a lower risk of cigarette use initiation. This multi-informant prospective study demonstrates that early individual differences in psychological functioning predict risk of future substance use initiation and highlights the importance of considering temperament and personality when assessing risk of future substance use initiation.

Self-Concept Profiles of Youth at Risk for Maladaptive Behaviors

Early alcohol use places youth at risk for adverse health, academic, and legal consequences. We examined the content of the total array of self-cognitions in urban youth to determine whether specific self-concept profiles were associated with early drinking, drinking-related self-cognitions, and conduct problems. We conducted a secondary analysis of data from a cross-sectional study with 9- to 12-year-old predominantly Black and Hispanic youth (N = 79) who attended urban school and summer youth programs. Measures included an open-ended self-description task and questionnaires to measure presence/absence of a drinking-related self-cognition, alcohol use, and conduct problems. We content analyzed 677 self-descriptors; cluster analysis revealed six unique self-concept profile groups. In a cluster group distinguished by negative self-content, 37% drank alcohol and 42% had a drinking-related self-cognition. Youth in this group also had conduct problems. School nurses are in prime positions to identify and intervene with youth who have at-risk self-concept profiles.

Association Between Psychosocial Problems and Unhealthy Health Behavior Patterns Among Finnish Adolescents

The aim of the study was to investigate how psychosocial problems in childhood and adolescence associate with an unhealthy health behavior pattern among adolescents in Northern Finland. The study population consisted of 4350 participants, drawn from the Northern Finland Birth Cohort 1986 Study. Health behavior patterns were assessed in adolescence and psychosocial problems in childhood and adolescence. Logistic regression analyses were performed to determine the associations. Several psychosocial problems predicted greater likelihood of engaging in unhealthy health behavior pattern. Externalizing problems in childhood predicted greater likelihood of engaging in unhealthy behavior patterns for girls. For both genders, externalizing problems and inattention in adolescence were associated with unhealthy health behavior patterns. Boys and girls with externalizing problems both in childhood and adolescence had an increased risk of unhealthy patterns. Psychosocial problems contribute to unhealthy lifestyles and should therefore be acknowledged when designing and targeting health promotion strategies aimed at adolescents.

Contribution of the Five Factors of Personality and Peers on Adolescent Alcohol Use: A Cross-National Study

Personality characteristics such as extraversion, low agreeableness and low conscientiousness are relevant for alcohol use during adolescence. In addition, having friends who use alcohol is one of the strongest predictors of adolescent alcohol consumption and its negative outcomes. The selection model posits that friends display similar alcohol consumption when their friendships are formed on the basis of common characteristics as, among others, personality. Thus, the aim of this study was to examine the mediation role of peers in the association between the five-factor model of personality and adolescent alcohol use in two cultures. One hundred and twenty Scottish and 221 Spanish respondents, all aged 12-15 years, answered the Alcohol Intake Scale (AIS). Adolescents were asked about the alcohol used at the weekend and also about the alcohol consumed by their friends. Scottish adolescents' personality was measured by the NEO Personality Inventory-3 (NEO-PI-3). The Junior Spanish version of the Revised NEO Personality Inventory (JS NEO) was used to assess personality in the Spanish sample. Low agreeableness and low conscientiousness correlated with own alcohol quantity in both countries. We performed an independent structural equation modeling for each country. Extraversion (β = .205, p < .05) and low agreeableness (β = -.196, p < .01) for Scottish adolescents, and low conscientiousness (β = -.175, p < .05) for Spanish youths, predicted alcohol use through peer alcohol consumption at weekends. These findings support the relevance of personality traits and peer affiliation in relation to alcohol consumption in adolescence.

A Developmental Social Neuroscience Model for Understanding Pathways to Substance Use Disorders During Adolescence

Adolescence is a transitional period of development characterized by critical changes in physical, neural, cognitive, affective, and social functions. Studies investigating the underlying mechanisms of substance use at levels of self-report, brain response, and behavioral data are generally consistent with suggestions from dual-process model that differential growth rates of frontally mediated control and striato-frontal reward processing are related to a heightened risk of substance use during adolescence. However, social theories highlight the important role of social context and environment in which adolescents grow up and suggest that growing up in an unfavorable environment and in particular exposure to adverse childhood experiences play a huge role in how this vulnerability is translated into actual risk. In this review, we provide a summary of recent theories that examine a number of key individual and social and environmental risk factors underlying risk for early initiation and escalation of substance misuse. We also present a model that expands the dual-process model to incorporate the role of negative self-concept and negative affect associated with growing up in an unfavorable environment and their interactions with cognitive control and inhibition to further explain vulnerability to early initiation and development of substance misuse in adolescents.

Post-GWAS in Psychiatric Genetics: A Developmental Perspective on the "Other" Next Steps

As psychiatric genetics enters an era where gene identification is finally yielding robust, replicable genetic associations and polygenic risk scores, it is important to consider next steps and delineate how that knowledge will be applied to ultimately ameliorate suffering associated with substance use and psychiatric disorders. Much of the post-genome-wide association study discussion has focused on the potential of genetic information to elucidate the underlying biology and use this information for the development of more effective pharmaceutical treatments. In this review we focus on additional areas of research that should follow gene identification. By taking genetic findings into longitudinal, developmental studies, we can map the pathways by which genetic risk manifests across development, elucidating the early behavioral manifestations of risk, and studying how various environments and interventions moderate that risk across developmental stages. The delineation of risk across development will advance our understanding of mechanism, sex differences and risk and resilience processes in different racial/ethnic groups. Here, we review how the extant twin study literature can be used to guide these efforts. Together, these new lines of research will enable us to develop more informed, tailored prevention and intervention efforts.

A GABRA2 polymorphism improves a model for prediction of drinking initiation

BACKGROUND

Survival analysis was used to explore the addition of a single nucleotide polymorphism (SNP) and covariates (sex, interview age, and ancestry) on a previously published model's ability to predict onset of drinking. A SNP variant of rs279871, in the chromosome 4 gene encoding gamma-aminobutyric acid receptor (GABRA2), was selected due to its associations with alcoholism in young adults and with behaviors that increased risk for early drinking.

METHODS

A subsample of 674 adolescents (ages 14-17) participating in the Collaborative Study on the Genetics of Alcoholism (COGA) was examined using a previously derived Cox proportional hazards model containing: 1) number of non-drinking related conduct disorder (CD) symptoms, 2) membership in a high-risk alcohol-dependent (AD) family, 3) most best friends drank (MBFD), 4) Achenbach Youth Self Report (YSR) externalizing score, and 5) YSR social problems score. The above covariates along with the SNP variant of GABRA2, rs279871, were added to this model. Five new prototype models were examined. The most parsimonious model was chosen based on likelihood ratio tests and model fit statistics.

RESULTS

The final model contained four of the five original predictors (YSR social problems score was no longer significant and hence dropped from subsequent models), the three covariates, and a recessive GABRA2 rs279871 TT genotype (two copies of the high-risk allele containing thymine). The model indicated that adolescents with the high-risk TT genotype were more likely to begin drinking than those without this genotype.

CONCLUSIONS

The joint effect of the gene (rs279871 TT genotype) and environment (MBFD) on adolescent alcohol initiation is additive, but not interactive, after controlling for behavior problems (CD and YSR externalizing score). This suggests that the impact of the high-risk TT genotype on the onset of drinking is affected by controlling for peer drinking and does not include genotype-by-environment interactions.

Opposed effects of hyperthymic and cyclothymic temperament in substance use disorder (heroin- or alcohol-dependent patients)

INTRODUCTION

In the last decade, the comprehension of affective temperaments has helped us to outline the boundaries of mood disorders, and to expand our knowledge of nosographic areas other than those of affectivity, even if affectivity is closely related to them. In the field of substance use disorders, the temperamental profile of heroin addicts and alcoholics has been discussed elsewhere, but no comparison has yet been made between these two patient populations. Such a comparison would help to shed light on the pathogenetic mechanisms that link temperament with substance abuse.

METHODS

63 Heroin Use Disorder (HUD) and 94 Alcohol Use Disorder (AUD) patients were compared with 130 healthy controls, with the aim of outlining affective temperament quantity and typology according to the formulation of Akiskal and Mallya.

RESULTS

Cyclothymic temperamental quantity differentiated - both at the univariate and multivariate levels - between patients who had various different types of Substance Use Disorder, largely irrespective of the principal substance of abuse (heroin or alcohol); irritable temperament quantity differentiated HUD patients from AUD patients. Hyperthymic temperament typology seemed to be more frequent in healthy controls at both univariate and multivariate levels.

LIMITATION

Cross-sectional study.

CONCLUSIONS

Our analyses suggest that cyclothymic temperament quantity could best correspond to the temperamental profile of Substance Use Disorder patients independently of principal substance of abuse (alcohol or heroin), and that irritable temperament quantity may differentiate HUD from AUD patients. Hyperthymic temperament typology seemed to be highly protective for HUD and, though a bit less, for AUD patients, and was a typical feature of healthy controls.

Polygenic Risk, Personality Dimensions, and Adolescent Alcohol Use Problems: A Longitudinal Study

OBJECTIVE

Alcohol use problems are common during adolescence and can predict serious negative outcomes in adulthood, including substance dependence and psychopathology. The current study examines the notion that alcohol use problems are driven by polygenic influences and that genetic influences may indirectly affect alcohol use problems through multiple pathways of risk, including variations in personality.

METHOD

We used a genome-wide approach to examine associations between genetic risk for alcohol use problems, personality dimensions, and adolescent alcohol use problems in two separate longitudinal population-based samples, the Finnish Twin Cohort (FinnTwin12) and the Avon Longitudinal Study of Parents and Children (ALSPAC). Participants were 1,035 young adults from FinnTwin12 and 3,160 adolescents from ALSPAC. Polygenic risk scores (PRS) were calculated for ALSPAC using genome-wide association results (on alcohol dependence symptoms as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) from FinnTwin12. A parallel multiple mediator model was tested to examine whether the association between PRS and alcohol use problems assessed at age 16 could be explained by variations in personality dimensions assessed at age 13, including sensation seeking and negative emotionality.

RESULTS

PRS were marginally predictive of age 16 alcohol use problems; this association was partially mediated by sensation seeking. Polygenic variation underlying risk for alcohol use problems may directly influence the effects of sensation seeking, which in turn influence the development of alcohol use problems in later adolescence.

CONCLUSIONS

These findings contribute to the increasing evidence regarding the salience of sensation seeking during early adolescence as a potential constituent in the risk pathway underlying the development of alcohol use problems.

Studies using macaque monkeys to address excessive alcohol drinking and stress interactions

The use of non-human primates (NHPs) in studies of volitional, oral self-administration of alcohol can help address the complex interplay between stress and excessive alcohol consumption. There are aspects to brain, endocrine and behavior of NHPs, particularly macaques, that provide a critical translational link towards understanding the risks and consequences of alcohol use disorders (AUDs) in humans. These include wide individual differences in escalating daily alcohol intake, accurate measures of hypothalamic-pituitary-adrenal (HPA) axis hormonal interactions, neuroanatomical specificity of synaptic adaptations to chronic alcohol, genetic similarities to humans, and the ability to conduct in vivo brain imaging. When placed in a framework that alcohol addiction is a sequence of dysregulations in motivational circuitry associated with severity of AUD, the NHP can provide within-subject information on both risks for and consequences of repeatedly drinking to intoxication. Notably, long-term adaptations in neurocircuitry that mediate behavioral reinforcement, stress responses and executive functions are possible with NHPs. We review here the substantial progress made using NHPs to address the complex relationship between alcohol and stress as risk factors and consequences of daily drinking to intoxication. This review also highlights areas where future studies of brain and HPA axis adaptations are needed to better understand the mechanisms involved in stress leading to excessive alcohol consumption. This article is part of the Special Issue entitled "Alcoholism".

Aggressive temperament predicts ethanol self-administration in late adolescent male and female rhesus macaques

RATIONALE

Anxiety and aggression are associated with ethanol self-administration, but these behaviors can serve as either risk factors for or consequences of heavy drinking in rodents and humans. Baseline levels of aggressive-like and anxious-like behavior in non-human primates have not yet been characterized in relation to future or prior ethanol intake.

OBJECTIVE

The objective of the study was to test the association between temperament at baseline with future ethanol self-administration in late adolescent male (n = 21) and female (n = 11) rhesus monkeys.

METHODS

Shortly after entering the laboratory and before exposure to ethanol, the Human Intruder Test (HIT) and the Novel Object Test (NOT) were used to determine baseline anxious-like and aggressive-like behavior in age-matched male and female rhesus monkeys (Macaca mulatta). The monkeys were induced to drink ethanol 4 % (w/v) using a schedule-induced polydipsia procedure, followed by "open-access" ethanol self-administration in which the monkeys were allowed a choice of water or 4 % ethanol (w/v) for 22 h/day for 52 weeks.

RESULTS

Aggressive monkeys self-administered more ethanol and attained higher blood ethanol concentrations (BECs). No significant differences in ethanol intakes or BECs were found between anxious and non-anxious monkeys or between behaviorally inhibited and non-inhibited monkeys. Baseline aggressive behavior positively correlated with ethanol intake and intoxication.

CONCLUSIONS

Baseline reactive aggression was associated with higher future ethanol intake and intoxication. While significant sex differences in HIT reactivity were observed, the relationship between aggression and ethanol drinking was observed across sex and is not sex-specific.

Posttraumatic stress disorder and alcohol dependence: Epidemiology and order of onset

OBJECTIVE

Posttraumatic stress disorder (PTSD) and alcohol dependence (AD) frequently co-occur; however, epidemiologic studies of temporal associations between PTSD and AD are limited. The aims of this study were (a) to investigate the bidirectional associations between PTSD and AD and (b) to examine demographic and clinical correlates of order-of-onset among individuals with PTSD and AD.

METHOD

Participants were 11,103 adults (60.6% women; Mage = 48.7 years, SD = 15.9) from the National Epidemiologic Survey on Alcohol and Related Conditions who endorsed lifetime alcohol consumption and DSM-IV PTSD Criterion A trauma exposure (American Psychiatric Association, 2000). Cox proportional hazards models with time-dependent covariates were used to evaluate bidirectional associations between PTSD and AD. Sex differences were assessed using stratified analyses.

RESULTS

After adjusting for demographic, trauma, and alcohol characteristics, PTSD was associated with greater likelihood of subsequent AD (hazard ratio [HR] = 1.359, 95% CI = 1.357-1.362), and AD was associated with greater likelihood of subsequent PTSD (HR = 1.274, 95% CI = 1.271-1.277). Bidirectional associations between PTSD and AD were stronger for women compared with men. Among individuals with PTSD and AD, initial onset of PTSD was associated with younger age of first potentially traumatic event. Initial onset of AD was associated with earlier initiation of alcohol use, earlier onset of heavy alcohol use, family history of alcohol problems, and history of generalized anxiety disorder and social anxiety disorder for women but not men. Initial AD was associated with lifetime panic disorder for men and women.

CONCLUSIONS

Etiology of PTSD and AD is heterogeneous, and order of onset may reflect differing risk pathways. (PsycINFO Database Record

Associations Between Gestational Age at Birth and Alcohol Use in the Avon Longitudinal Study of Parents and Children

BACKGROUND

The relationship between gestational age at birth (GA) and alcohol use measures in early adulthood was examined in a large U.K. community-based birth cohort (Avon Longitudinal Study of Parents and Children).

METHODS

A series of linear and logistic regression models were used to test for main effects of a continuous measure of GA on a range of alcohol use measures, and moderation of these associations by sex. In addition, mediation analyses assessed the extent to which significant associations between GA and alcohol use operated indirectly, through influences of the parental environment and/or childhood measures of emotional and behavioral health (EBH).

RESULTS

Earlier GA significantly predicted never drinking by age 18, but was not associated with other measures of alcohol use behavior among young adult drinkers (i.e., Self-Rating of the Effects of Alcohol, Alcohol Use Disorders Identification Test, or DSM-IV-TR Criteria for Alcohol Dependence). The association between earlier GA and never drinking by age 18 was moderated by sex, such that females born early were less likely to have ever had a drink by age 18. In the full sample, childhood measures of EBH were found to mediate the association between earlier GA and never drinking by age 18. This association was not mediated by parenting factors.

CONCLUSIONS

Earlier GA is associated with never drinking alcohol in early adulthood, in females. Emotional and behavioral difficulties experienced in early childhood may mediate the relationship between earlier GA and never drinking by age 18.

Annual Research Review: On the developmental neuropsychology of substance use disorders

BACKGROUND

Adolescence represents a period of development during which critical biological, as well as social and cognitive, changes occur that are necessary for the transition into adulthood. A number of researchers have suggested that the pattern of normative brain changes that occurs during this period not only predisposes adolescents to engage in risk behaviours, such as experimentation with drugs, but that they additionally make the adolescent brain more vulnerable to the direct pharmacological impact of substances of abuse. The neural circuits that we examine in this review involve cortico-basal-ganglia/limbic networks implicated in the processing of rewards, emotion regulation, and the control of behaviour, emotion and cognition.

FINDINGS AND CONCLUSIONS

We identify certain neurocognitive and personality/comorbidity-based risk factors for the onset of substance misuse during adolescence, and summarise the evidence suggesting that these risk factors may be further impacted by the direct effect of drugs on the underlying neural circuits implicated in substance misuse vulnerability.

Integrating basic research with prevention/intervention to reduce risky substance use among college students

Too often basic research on etiological processes that contribute to substance use outcomes is disconnected from efforts to develop prevention and intervention programming. Substance use on college campuses is an area of concern where translational efforts that bring together basic scientists and prevention/intervention practitioners have potential for high impact. We describe an effort at a large, public, urban university in the United States to bring together researchers across the campus with expertise in college behavioral health with university administration and health/wellness practitioners to address college student substance use and mental health. The project “Spit for Science” examines how genetic and environmental influences contribute to behavioral health outcomes across the college years. We argue that findings coming out of basic research can be used to develop more tailored prevention and intervention programming that incorporates both biologically and psychosocially influenced risk factors. Examples of personalized programming suggest this may be a fruitful way to advance the field and reduce risky substance use.

Genes associated with alcohol outcomes show enrichment of effects with broad externalizing and impulsivity phenotypes in an independent sample

OBJECTIVE

The purpose of this study was to evaluate evidence for association with a panel of genes previously associated with alcohol-related traits in a new sample of adolescent and young adult individuals (N = 2,128; 51% female) collected as part of the Collaborative Study on the Genetics of Alcoholism (COGA). We tested for association with phenotypes related to externalizing behavior, including diagnostic symptom counts for disorders on the externalizing spectrum (alcohol dependence, conduct disorder, adult antisocial personality disorder, and illicit drug dependence), and related behavioral/personality traits (Achenbach Externalizing, NEO Extraversion, NEO Conscientiousness, Zuckerman's Sensation Seeking, and the Barratt Impulsivity Scale) based on the substantial literature suggesting that these behaviors may be alternate manifestations of a shared genetic liability.

METHOD

We tested for overall enrichment of the set of 215 genotyped single-nucleotide polymorphisms (SNPs) for each of the phenotypes. We conducted secondary analyses comparing results for sensation seeking with results for the other phenotypes.

RESULTS

For all phenotypes, there was significant enrichment of association results (p < .05) compared with chance expectations. The greatest number of significant results was observed with the phenotype Sensation Seeking. Secondary analyses indicated that the number of SNPs yielding p < .05 with Sensation Seeking was significantly greater than that observed for each of the other phenotypes.

CONCLUSIONS

We find evidence for enrichment of association results across a spectrum of externalizing phenotypes with a panel of candidate genes/SNPs selected based on previous suggestion of association with alcohol-related outcomes. In particular, we find significant enrichment of effects with sensation seeking, suggesting that this may be a particularly salient behavior associated with risk for alcohol-related problems.

Does adolescent weight status predict problematic substance use patterns?

OBJECTIVES

To identify underlying patterns of cigarette smoking, alcohol use, and marijuana use in young adulthood, and ascertain whether adolescent overweight or obesity status predicts problematic substance use patterns.

METHODS

The study included 15,119 participants from the National Longitudinal Study of Adolescent Health (Add Health) at Wave 1 (11-19 years) and Wave 3 (18-26 years). Latent class analysis was conducted.

RESULTS

Participants were classified into a Low Substance Use (35%), Regular Smokers (12%), High-risk Alcohol use (33%), or High Substance Use (20%) class. Overweight/obese adolescents had a greater likelihood of belonging to the Regular Smokers class.

CONCLUSIONS

Overweight/obese adolescents are at higher risk of engaging in regular cigarette smoking without problematic alcohol or marijuana use.

Harmonization of Neuroticism and Extraversion phenotypes across inventories and cohorts in the Genetics of Personality Consortium: an application of Item Response Theory

Mega- or meta-analytic studies (e.g. genome-wide association studies) are increasingly used in behavior genetics. An issue in such studies is that phenotypes are often measured by different instruments across study cohorts, requiring harmonization of measures so that more powerful fixed effect meta-analyses can be employed. Within the Genetics of Personality Consortium, we demonstrate for two clinically relevant personality traits, Neuroticism and Extraversion, how Item-Response Theory (IRT) can be applied to map item data from different inventories to the same underlying constructs. Personality item data were analyzed in >160,000 individuals from 23 cohorts across Europe, USA and Australia in which Neuroticism and Extraversion were assessed by nine different personality inventories. Results showed that harmonization was very successful for most personality inventories and moderately successful for some. Neuroticism and Extraversion inventories were largely measurement invariant across cohorts, in particular when comparing cohorts from countries where the same language is spoken. The IRT-based scores for Neuroticism and Extraversion were heritable (48 and 49 %, respectively, based on a meta-analysis of six twin cohorts, total N = 29,496 and 29,501 twin pairs, respectively) with a significant part of the heritability due to non-additive genetic factors. For Extraversion, these genetic factors qualitatively differ across sexes. We showed that our IRT method can lead to a large increase in sample size and therefore statistical power. The IRT approach may be applied to any mega- or meta-analytic study in which item-based behavioral measures need to be harmonized.

Dopamine ups and downs in vulnerability to addictions: a neurodevelopmental model

Addictions are commonly presaged by problems in childhood and adolescence. For many individuals this starts with the early expression of impulsive risk-taking, social gregariousness, and oppositional behaviors. Here we propose that these early diverse manifestations reflect a heightened ability of emotionally salient stimuli to activate dopamine pathways that foster behavioral approach. If substance use is initiated, these at-risk youth can also develop heightened responses to drug-paired cues. Through conditioning and drug-induced sensitization, these effects strengthen and accumulate, leading to responses that exceed those elicited by other rewards. At the same time, cues not paired with drug become associated with comparatively lower dopamine release, accentuating further the difference between drug and non-drug rewards. Together, these enhancing and inhibiting processes steer a pre-existing vulnerability toward a disproportionate concern for drugs and drug-related stimuli. Implications for prevention and treatment are discussed.

Dimensions of parental alcohol use/problems and offspring temperament, externalizing behaviors, and alcohol use/problems

BACKGROUND

Alcohol consumption (AC) and alcohol problems (AP) are complex traits. How many factors reflecting parental AC and AP are present in the large prospectively followed Avon Longitudinal Study of Parents and Children cohort? Would these factors be uniquely associated with various temperamental and alcohol-related outcomes in the children?

METHODS

We factor-analyzed multiple items reflecting maternal and paternal AC and AP measured over a 12-year period from before the birth of the child (n = 14,093 families). We examined, by linear regression controlling for socioeconomic status, the relationship between scales derived from these factors and offspring early childhood temperament, externalizing traits, and adolescent AC and AP (ns ranging from 9,732 to 3,454).

RESULTS

We identified 5 coherent factors: typical maternal AC, maternal AC during pregnancy, maternal AP, paternal AC, and paternal AP. In univariate analyses, maternal and paternal AC and AP were modestly and significantly associated with low shyness, sociability, hyperactivity, and conduct problems in childhood and early adolescence; delinquent behavior at age 15; and AC and AP at ages 15 and 18. AC and AP at age 18 were more strongly predicted by parental factors than at age 15. Maternal AC during pregnancy uniquely predicted externalizing traits at ages 4, 13, and 15.

CONCLUSIONS

Parental AC and AP are complex multidimensional traits that differ in their association with a range of relevant measures in their children. Controlling for background AC and AP, self-reported levels of maternal AC during pregnancy uniquely predicted externalizing behaviors in childhood and adolescence.