The effects of age at drinking onset and stressful life events on alcohol use in adulthood: a replication and extension using a population-based twin sample

The joint effects of genetic liability and the death of close relatives on risk for major depression and alcohol use disorder in a Swedish national sample

BACKGROUND

To determine whether genetic risk factors for major depression (MD) and alcohol use disorder (AUD) interact with a potent stressor - death of spouse, parent, and sibling - in predicting episodes of, respectively, MD and AUD.

METHODS

MD and AUD registrations were assessed from national Swedish registries. In individuals born in Sweden 1960-1970, we identified 7586, 388 459, and 34 370 with the loss of, respectively, a spouse, parent, and sibling. We started following subjects at age 18 or the year 2002 with end of follow-up in 2018. We examined time to event - a registration for MD within 6 months or AUD within a year - on an additive scale, using the Nelson-Aalen estimator. Genetic risk was assessed by the Family Genetic Risk Score (FGRS).

RESULTS

In separate models controlling for the main effects of death of spouse, parent, and sibling, FGRS, and sex, significant interactions were seen in all analyses between genetic risk for MD and death of relative in prediction of subsequent MD registration. A similar pattern of results, albeit with weaker interaction effects, was seen for genetic risk for AUD and risk for AUD registration. Genetic risk for bipolar disorder (BD) and anxiety disorders (AD) also interacted with event exposure in predicting MD.

CONCLUSIONS

Genetic risk for both MD and AUD act in part by increasing the sensitivity of individuals to the pathogenic effects of environmental stressors. For prediction of MD, similar effects are also seen for genetic risk for AD and BD.

Death of parent, sibling, spouse, and child in a Swedish national sample and risk of subsequent stress reaction, major depression, alcohol-use disorder, and drug-use disorder

BACKGROUND

To determine, in a general population, how much rates of stress reactions (SR), major depression (MD), alcohol-use disorder (AUD) and drug-use disorder (DUD) increase after the death of close relatives.

METHODS

SR, MD, AUD, and DUD registrations were assessed from national Swedish registries. From the population followed from 2000 to 2018, those exposed to death of a close relative in 2002-2016 were matched to unexposed controls and analyzed in males and females by a controlled pre-post design using a difference-in-difference method.

RESULTS

Substantial, brief increases in risk for SR and more modest prolonged increases in MD were observed after death of relatives in both men and women greatest with children, followed by spouses, parents, and siblings. Relatively long-lasting modest increases in AUD but not DUD were also observed following death of relatives. The absolute increases for SR and MD were greater in females than males and for AUD greater in males than females. However, logistic regression analyses showed most effects did not differ significantly by sex. Consistently larger increases in disorder risk were seen with the death of younger v. older parents, siblings, and spouses and with accidental v. non-accidental death in children.

CONCLUSIONS

Applying a matched cohort design to Swedish population registries, death of close relatives was associated with, and likely caused, substantial increases in rates of SR, MD, and AUD, consistent with smaller prior clinical investigations. Through such registries, we can, in large representative samples, integrate the impact of exposures to selected environmental adversities into disorder risk pathways.

Physical activity, use of alcohol and smoking in middle-aged and aging men. A longitudinal study among Finnish male former athletes and controls

It is not known whether decrease in physical activity (PA) is associated with binge drinking among former athletes. The purpose of this study was to investigate the reciprocal associations between PA and use of alcohol among former athletes and controls at four time points. Furthermore, we examined whether there were longitudinal latent profiles related to use of alcohol, smoking and PA during the follow-up. Finnish male former elite athletes (n = 1633) and matched controls (n = 1099) questionnaire-reported their PA, alcohol consumption and smoking at four time points in 1985, 1995, 2001 and 2008. Former athletes were more physically active and smoked less than controls, but in all profiles smoking decreased during the follow-up. Former athletes consumed alcohol significantly more compared to controls in 1985, especially if their athletic career had ended suddenly by sports injury. At other time points, no differences were seen. Five latent profiles were found, and there were significant differences between former athletes and controls in the probabilities to belong to four of them. PA decreased in four of five profiles, while alcohol consumption decreased or increased in some profiles. But PA did not predict later alcohol consumption at any time point. Cross-lagged path model indicated that the mutual associations of alcohol use and PA were weak at most. Although risk of excessive alcohol consumption may increase in individuals, whose athletic career has ended suddenly by sports injury, overall PA and alcohol affected each other's development only modestly among former athletes and controls during the 23-year follow-up.

Consequences of alcohol use, and its association with psychological distress, sensitivity to emotional contagion and age of onset of alcohol use, in Uruguayan youth with or without college degree

Psychological distress can promote alcohol consumption during emerging adulthood. Still unknown is, however, how predisposition to emotional contagion alters psychological distress, and how these phenomena are affected by level of education. The present study analyzed the effect of psychological distress, age of first contact with alcohol (early, late), and predisposition to emotional contagion on alcohol-induced negative consequences and on the volume of alcohol consumed during the last year. We also described alcohol-use behaviors as a function of sex, maximum level of education and age of first contact with alcohol, in 1505 youth from Uruguay (18-30 years). A survey measured alcohol use (Alcohol Use Disorders Identification Test and ad-hoc questionnaire), negative consequences of alcohol use [young adult alcohol consequences questionnaire (YAACQ)], psychological distress (Kessler scale) and proclivity to emotional contagion (Doherty Emotional contagion scale). The patterns of alcohol use were greater in men vs. women and in those featuring an early age of first alcohol use, yet similar in college and non-college graduates. Early drinkers had greater levels of psychological distress than late-onset drinkers. There was a significant bivariate and multiple correlation between psychological distress and the number of negative consequences of alcohol experienced during the last year, which remained significant even after controlling for total volume of alcohol consumed. Significant associations emerged between YAACQ scores and frequency of heavy episodic or binge drinking, and between psychological distress and emotional contagion, but not between emotional contagion and any of the remaining variables. Psychological distress was not significantly correlated with heavy episodic or binge drinking. The study indicates that, during adolescence and youth, psychological distress is associated with experiencing negative consequences of alcohol consumption. The study also suggested that greater levels of psychological distress may underlie the facilitating effect of an early age of drinking onset upon alcohol drinking patterns.

Early Alcohol and Smoking Initiation: A Contributor to Sexual Minority Disparities in Adult Use

INTRODUCTION

Lesbian, gay, and bisexual adults report higher rates of smoking and alcohol use than heterosexual peers. Prior studies have not examined whether potential disparities in early initiation among lesbian, gay, and bisexual youth may contribute to adult disparities.

METHODS

Data on 126,463 adults (including 8,241 lesbian, gay, and bisexual adults) were from the 2015-2017 National Survey on Drug Use and Health. Rates of reported early alcohol and smoking initiation (before age 15 years) among both lesbian/gay and bisexual adults were examined relative to same-gender heterosexual adults. Mediation analyses were used to assess whether early initiation differences contribute to disparities in adult heavy episodic drinking, alcohol use disorder, current smoking, and nicotine dependence for each subgroup. Analyses were conducted in 2018-2019.

RESULTS

For both lesbian/gay and bisexual women, early alcohol initiation rates were elevated and explained 21%-38% of their observed disparities in adult heavy episodic drinking and alcohol use disorder. Similarly, early smoking initiation rates were elevated among both lesbian/gay and bisexual women and explained 22%-29% of their disparities in adult smoking and nicotine dependence. By contrast, no evidence was observed that early initiation mediated adult disparities for gay or bisexual men.

CONCLUSIONS

A significant proportion of alcohol and smoking disparities among lesbian/gay and bisexual women in adulthood appear attributable to early initiation, indicating the need for enhanced early prevention efforts for these groups. Making routine adolescent screening for substance use, brief intervention, and referral to treatment more culturally sensitive to lesbian, gay, and bisexual youth may also be an important step in reducing adult disparities for lesbian, gay, and bisexual women.

Alcohol Use by Youth

Alcohol use continues to be a major concern from preadolescence through young adulthood in the United States. Results of recent neuroscience research have helped to elucidate neurobiological models of addiction, substantiated the deleterious effects of alcohol on adolescent brain development, and added additional evidence to support the call to prevent and reduce underage drinking. This technical report reviews the relevant literature and supports the accompanying policy statement in this issue of Pediatrics.

Impact of a brief psychoeducational intervention for reducing alcohol use and related harm in school leavers

INTRODUCTION AND AIMS

Many young people engage in risky partying behaviours and excessive alcohol use in the transition period following high school graduation. Despite this, there is limited longitudinal research on adolescents before and after school graduation; and limited evaluation of interventions targeting these high-risk periods. The present study aims to address this gap in the literature by examining the impact of brief psychoeducation interventions on substance use, psychological distress and well-being during this important life transition.

DESIGN AND METHODS

Participants were 334 high school leavers (53% female, M_age  = 17.14) from Queensland, Australia. They received either: (i) a psychoeducation intervention on safe partying behaviours; (ii) a reconstructed version of the psychoeducation intervention; or (iii) a standard health curriculum control. Surveys were conducted at baseline; 2 weeks, immediately following post-graduation celebratory event 'Schoolies'; and 4 months, immediately following university orientation 'O-week'.

RESULTS

Significant time by group effects were found for problem drinking, F(2, 227) = 3.07, P < 0.05, and well-being, F(4, 439) = 3.54, P < 0.01. There was stability in problem drinking from baseline to follow-up for the psychoeducation groups but small increases in problem drinking for the control (d = 0.12). Both psychoeducation groups had improvements in well-being scores from baseline to post-Schoolies (d = 0.40; 0.20), which were maintained across time. In contrast, the control condition showed a decrease in well-being scores from baseline to the post O-week follow-up (d = 0.15).

DISCUSSION AND CONCLUSIONS

Brief school-based psychoeducational interventions may result in small improvements in well-being, and possibly stabilise the trajectory of problematic drinking in high-risk environments.

Stressful life events influence transitions among latent classes of alcohol use

Stressful life events (SLEs) have been associated with an increased risk of heavy drinking, suggesting individuals may use alcohol to cope with negative life events. However, little research has explored the extent to which SLEs have different effects on later alcohol use based on one's current alcohol use pattern. We replicated prototypical patterns of alcohol use via latent class analysis at Waves 2, 3, and 4 of the National Longitudinal Study of Adolescent to Adult Health (n = 4,569). Latent transition analysis was then used to examine the extent to which SLEs influenced the likelihood of stability or change in class membership from adolescence to early adulthood. Results suggested that adolescents were more likely to transition into different patterns of alcohol use as they entered early adulthood but were more likely to retain the same drinking pattern once in early adulthood. Among those who typically abstained, experiencing SLEs was associated with greater odds of transitioning to heavier drinking or problematic patterns of alcohol use. However, among those who had heavy or problematic alcohol use patterns, SLEs were associated with greater odds of decreasing alcohol use to either heavy or abstaining levels. Results suggest those who previously abstained may begin to use alcohol as a coping mechanism following stressful events, whereas those who drank heavily may decrease or abstain from alcohol use following life stress as a means of enacting positive life changes. The results encourage further study into factors that differentiate changes in alcohol use among light drinkers following SLEs. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Age of Onset of Alcohol Consumption and Subsequent Negative Health Outcomes in Gay and Bisexual Men Who Have Sex With Men

The correlation between current alcohol use and sexual risk behaviors among men who have sex with men (MSM) is well documented, but little is known about age of drinking onset and current risks among this population. Data from a 2008 Internet survey of 8,452 MSM in the United States were used to assess factors associated with age of onset of alcohol use. In a multivariable model, drinking onset before age 15 was significantly associated with a higher number of lifetime male anal sex partners and being behaviorally bisexual in the past 12 months. Men who reported depressive symptoms in the past two weeks or who screened positive for alcohol abuse in the past 60 days were more likely to have early age of drinking onset. Findings suggest the need for targeting younger adolescents for alcohol screening, particularly sexual minority youth, to prevent risk behaviors in adulthood.

Reciprocal relations between positive alcohol expectancies and peer use on adolescent drinking: An accelerated autoregressive cross-lagged model using the NCANDA sample

Positive alcohol expectancies (PAE) and associating with drinking peers are reliable predictors of adolescent alcohol use. Knowledge of when and for whom these risk factors are most influential could enhance intervention effectiveness. Reciprocal relations between PAE and adolescent and peer alcohol use were examined between the ages of 13 and 18 in a sample (N = 566; 50% female) from the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA), as well as sex differences in these associations. Associating with drinking peers prospectively predicted more frequent alcohol use for both sexes, although peer socialization was evident earlier for girls compared with boys. Higher PAE influenced later drinking in mid-adolescence, from age 14 to 16, for boys only. PAE influenced peer group selection for both sexes, although the influence was evident earlier in boys than girls. The relative impact of environmental risk factors for problematic alcohol use may vary over time and across developmental periods. These results suggest that prevention and treatment efforts for adolescent drinking can be improved by targeting age-appropriate risk factors. Early adolescent interventions may be best served by minimizing involvement with drinking peers and correcting normative beliefs of peer use. Among adolescent girls, early interventions focused on reducing peer influence may be most effective. Prevention and treatment programs aimed at addressing PAE would likely prove more effective for boys in mid- to late adolescence. (PsycINFO Database Record

ELSA 2016 Cohort: Alcohol, Tobacco, and Marijuana Use and Their Association with Age of Drug Use Onset, Risk Perception, and Social Norms in Argentinean College Freshmen

The transition from high school to college is a high-risk stage for the initiation and escalation of substance use. Substance use and its associated risk factors have been thoroughly described in developed countries, such as the United States, but largely neglected in Argentina, a South American country with patterns of a collectivist culture. The present cross-sectional study describes the occurrence of alcohol, tobacco, and marijuana use and the association between these behaviors and the age of onset of substance use and cognitive (i.e., risk perception) and social (i.e., prescriptive) variables in a large sample of Argentinean college freshmen (n = 4083, 40.1% men; mean age = 19.39 ± 2.18 years). The response rate across courses was ≥90% and was similarly distributed across sex. Participants completed a survey that measured substance use (alcohol [with a focus on heavy drinking and binge drinking behaviors], tobacco, and marijuana), age of onset of the use of each substance, perceived risk associated with various substance use behaviors, prescriptive norms associated with substance use, and descriptive norms for alcohol use (AU). The results indicated that AU is nearly normative (90.4 and 80.3% with last year and last month use, respectively) in this population, and heavy drinking is highly prevalent (68.6 and 54.9% with heavy episodic and binge drinking, respectively), especially among those with an early drinking onset (97.8 and 93.6% with last year and last month use and 87.8 and 76.3% with heavy episodic and binge drinking, respectively). The last-year occurrence of tobacco and marijuana use was 36 and 28%, respectively. Early substance use was associated with the greater use of that specific substance. The students overestimated their same-sex friend's AU, and women overestimated the level of AU of their best male friend. At the multivariate level, all of the predictors, with the exception of the parents' prescriptive norms, significantly explained the frequency of marijuana and tobacco use and frequency of hazardous drinking. Overall, despite important cultural and contextual differences between Argentina and the United States, our findings suggest that certain vulnerability factors have a similar influence across these cultural contexts.

Is 'age at first drink' a useful concept in alcohol research and prevention? We doubt that

AIM

To address and discuss the weaknesses of age at first drink (AFD) as a concept in alcohol research and prevention.

METHODS

Narrative literature review.

RESULTS

Varying from one sip to the consumption of several full drinks, and sometimes including the specification of particular conditions (e.g. without parental consent), no exact definition and operationalization of AFD was found. Evidence reveals poor test-retest reliability when the same individuals report their AFD two or more times. Theoretical arguments and empirical evidence fail to explain why having one sip or one drink earlier than peers should cause heavier drinking and related problems later in life. Alternative explanations such as self-selection, third variable effects and systematic report bias are not considered in most studies. These shortcomings also make AFD unsuitable as an indicator or marker of underlying problems such as conduct problems and academic failure. Together with unjustified causal inferences, this has led to an over-emphasis on the relevance of postponing AFD as a way to prevent problems later in life.

CONCLUSION

We argue in favour of shifting the focus of alcohol research and prevention away from AFD towards a better understanding of the progression from infrequent, low-quantity drinking to more detrimental drinking patterns and the prevention of associated acute and short-term harm.

Sex differences in the pathways to symptoms of alcohol use disorder: a study of opposite-sex twin pairs

BACKGROUND

We sought to develop an empirical, broad-based developmental model for sex differences in risk for symptoms of alcohol use disorders, here called alcohol problems (APs).

METHODS

We assessed 18 risk factors in 5 developmental tiers in both members of 1,377 opposite-sex dizygotic twin pairs from the Virginia population-based twin registry. Analyses were conducted by structural modeling, examining within-pair differences.

RESULTS

The best-fitting model explained 73% of the variance in men and 71% in women for last year AP. Forty-nine percent of paths differed significantly across sexes. Ten variables had appreciably different predictive effects on AP in males versus females. Three were stronger in females: familial risk, early-onset anxiety disorders, and nicotine dependence. Seven predictors had a stronger total effect in males: novelty seeking, conduct disorder, childhood sexual abuse, parental loss, neuroticism, low self-esteem, and low marital satisfaction.

CONCLUSIONS

In a co-twin control design, which matches sisters and brothers on genetic and familial-environmental background, we found numerous sex differences in predictors of last year AP. Factors that were more prominent in men and in women were diverse, reflecting both internalizing and externalizing psychopathology. The model was slightly more successful at predicting AP in men than in women.

A Long-Term Longitudinal Examination of the Effect of Early Onset of Alcohol and Drug Use on Later Alcohol Abuse

BACKGROUND

Early onset of alcohol use has been linked to later alcohol problems in adulthood. Currently, it is not clear whether early onset of marijuana and tobacco use similarly predicts alcohol problems. Moreover, most studies examining the effect of early substance use onset on later problems only have followed youth into their early 20s. Therefore, the primary goal of this study was to examine whether early onset of alcohol, marijuana, and tobacco use predicts alcohol problems beyond the transition to adulthood.

METHODS

The sample included 225 15-19-year-old youth (60% girls; 62% Caucasian) who were surveyed in three time periods: 1993-1998 (Time 1), 1998-2003 (Time 2), and 2003-2007 (Time 3). Participants reported their age of onset for regular drinking, tobacco use, and marijuana use. At each time of measurement, they also completed surveys relating to their alcohol use and abuse.

RESULTS

Participants with an earlier age of onset of drinking regularly scored higher on the Michigan Alcoholism Screening Test (MAST) and drank more frequently to get high and drunk throughout their 20s. Tobacco use onset and marijuana use onset were not associated with later alcohol use or abuse.

CONCLUSIONS

Results from this study suggest that the relationship between the onset of substance use and later substance abuse may be substance specific. Of note, early onset of regular drinking was associated with alcohol problems during adulthood, underscoring the importance of delaying the onset of regular alcohol use among youth.

Associations between exposure to stressful life events and alcohol use disorder in a longitudinal birth cohort studied to age 30

BACKGROUND

To examine associations between measures of stressful life events exposure and alcohol abuse/dependence (AAD) from ages 18 to 30 using data from a longitudinal birth cohort (n=987 to 1011).

METHODS

Outcome measures included DSM-IV (American Psychiatric Association, 1994) AAD symptoms and AAD, at ages 20-21, 24-25, and 29-30 years. Exposure to a range of stressful life events was measured during the periods 18-21, 21-25, and 25-30 years using items adapted from the social readjustment rating scale (Holmes and Rahe, 1967). Data were analysed using Generalised Estimating Equation models, adjusted for non-observed sources of confounding using conditional fixed effects regression. Further analyses examined: gender×life events exposure interactions, structural equation modelling of possible reciprocal causal pathways linking stressful life events and AAD symptoms, and an alternative conceptualization of the stressful life events measure.

RESULTS

After adjustment, those with the highest exposure to stressful life events had rates of AAD symptoms that were 2.24 (p<.0001) times higher, and odds of AAD that were 2.24 times higher(p<.01), than those at the lowest level of exposure. Associations between life events exposure and AAD symptoms were stronger for females than for males (p<.05), with results consistent using a count measure of stressful life events. Structural equation modelling showed that the best-fitting model was one in which life events influenced AAD symptoms.

CONCLUSIONS

The results suggest that there were persistent linkages between stressful life events and AAD, providing support for a stress-reduction model of alcohol consumption.

Serotonin transporter gene promoter polymorphism (5-HTTLPR) and alcohol use in general population: interaction effect with birth cohort

RATIONALE AND OBJECTIVE

Prevalence of alcohol use is markedly influenced by socioeconomic conditions and is therefore subject to cohort effects. The common genetic variation 5-HTTLPR (serotonin transporter gene-linked polymorphic region) has been related to several aspects of alcohol use and addiction but with mixed results, probably due to different environmental interaction effects. We aimed at assessing whether the association between alcohol use and 5-HTTLPR genotype is subject to cohort effects as birth cohorts may be raised in significantly different environments.

METHODS

We used the database of the Estonian Children Personality Behaviour and Health Study (beginning in 1998). Cohorts of initially 9-year-old (recalled at ages 15 and 18) and 15-year-old (recalled at ages 18 and 25) children provided self-reports on their alcohol use in all data collection waves (complete data available n = 1,075).

RESULTS

A significant genotype × gender × cohort interaction effect on the age of consuming the first alcoholic drink was found [F(2, 1,063) = 7.2, p < 0.001]. Females with the s/s genotype in the older cohort were the latest experimenters with alcohol, while the s/s females of younger cohort had tried alcohol earlier than any other group. In males, there was no significant cohort × genotype interaction, but the 5-HTTLPR genotype was associated with alcohol use, the s/s subjects reporting the highest consumption.

CONCLUSION

Expression of genetic vulnerability to alcohol use is influenced by birth cohort effects. The 5-HTTLPR genotype is associated with alcohol consumption in general population, but the effect depends on gender and birth cohort.

Causal influence of age at first drink on alcohol involvement in adulthood and its moderation by familial context

OBJECTIVE

Previous research has established a connection between early age at drinking initiation and greater alcohol involvement in adulthood, but it has not yet been established whether this is a causal effect. The current study used a multilevel discordant twin design to examine individual and contextual effects, and an interaction between these effects, of the age at drinking initiation on the frequency and quantity of drinking in adulthood.

METHOD

Participants were 4,194 same-sex twins (2,264 monozygotic, 1,924 dizygotic; 2,270 women; Mage = 29.9 years) from the Australian Twin Registry who completed a telephone interview that included assessments of the age at alcohol use initiation and past-year frequency and quantity of alcohol use. Multilevel models were estimated using data from the full sample and using data from only monozygotic twins. Individual (within-twin-pair comparison) and family contextual (between-twin-pair comparison) effects were estimated.

RESULTS

The age at first drink was related to the past-year frequency (r = -.16) and quantity of drinking (r = -.12) in young adulthood. Individual (causal) and family context effects of age at drinking onset predicted later adult drinking frequency and quantity. There was also a significant cross-level interaction between individual and family contexts for frequency but not quantity of drinking.

CONCLUSIONS

Results of this study indicate a potential causal effect of age at drinking onset on adult alcohol involvement as well as the importance of examining both individual and contextual effects in discordant twin studies.

Adolescents and alcohol: acute sensitivities, enhanced intake, and later consequences

Adolescence is an evolutionarily conserved developmental period characterized by notable maturational changes in the brain along with various age-related behavioral characteristics, including the propensity to initiate alcohol and other drug use and consume more alcohol per occasion than adults. After a brief review of adolescent neurobehavioral function from an evolutionary perspective, the paper will turn to assessment of adolescent alcohol sensitivity and consequences, with a focus on work from our laboratory. After summarizing evidence showing that adolescents differ considerably from adults in their sensitivity to various effects of alcohol, potential contributors to these age-typical sensitivities will be discussed, and the degree to which these findings are generalizable to other drugs and to human adolescents will be considered. Recent studies are then reviewed to illustrate that repeated alcohol exposure during adolescence induces behavioral, cognitive, and neural alterations that are highly specific, replicable, persistent and dependent on the timing of the exposure. Research in this area is in its early stages, however, and more work will be necessary to characterize the extent of these neurobehavioral alterations and further determine the degree to which observed effects are specific to alcohol exposure during adolescence.

Genetic and neurophysiological correlates of the age of onset of alcohol use disorders in adolescents and young adults

Discrete time survival analysis was used to assess the age-specific association of event-related oscillations (EROs) and CHRM2 gene variants on the onset of regular alcohol use and alcohol dependence. The subjects were 2,938 adolescents and young adults ages 12-25. Results showed that the CHRM2 gene variants and ERO risk factors had hazards which varied considerably with age. The bulk of the significant age-specific associations occurred in those whose age of onset was under 16. These associations were concentrated in those subjects who at some time took an illicit drug. These results are consistent with studies which associate greater rates of alcohol dependence among those who begin drinking at an early age. The age specificity of the genetic and neurophysiological factors is consistent with recent studies of adolescent brain development, which locate an interval of heightened vulnerability to substance use disorders in the early to mid teens.

Shared genetic contributions to early-onset drinking and drinking to cope motives

INTRODUCTION

Recent evidence from empirical studies indicates that individuals who begin drinking at an early age may be more likely to use alcohol to cope with negative mood states and stress; however, the mechanisms underlying this association are unclear. One possibility is that early drinking directly increases risk for drinking to cope (DTC). Alternatively, the association between early drinking and DTC may be indirect, attributable to overlapping genetic or environmental factors. No prior genetically informative study has investigated the sources of covariation underlying the early-onset drinking-DTC association.

METHOD

Early-onset drinking (before age 15) was assessed using structured clinical interviews in a sample of 7130 male and female participants aged 19-56 years from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders (VATSPSUD, Kendler & Prescott, 2006). DTC was assessed using the mood management scale of the alcohol use inventory (Horn & Wanberg, 1983). The sources of the covariation between early first drink and DTC were estimated using bivariate twin modeling.

RESULTS

Early drinking onset was reported by 28% of males and 16% of females and was associated with significantly higher DTC scores (phenotypic correlation: males = .19, females = .22). Results from bivariate twin models indicated that the association between early-onset drinking and DTC was completely attributable to shared genetic factors that contribute to both behaviors.

CONCLUSIONS

Greater DTC among early-onset drinkers may not reflect a direct causal process, as shared biological pathways may explain vulnerability to stress-related drinking seen among early-onset drinkers.

Interactive effects of childhood maltreatment and recent stressful life events on alcohol consumption in adulthood

OBJECTIVE

Childhood maltreatment is associated with early alcohol use initiation, alcohol-related problem behaviors, and alcohol use disorders in adulthood. Heavy drinking risk among individuals exposed to childhood maltreatment could be partly attributable to stress sensitization, whereby early adversity leads to psychobiological changes that heighten sensitivity to subsequent stressors and increase risk for stress-related drinking. We addressed this issue by examining whether the association between past-year stressful life events and past-year drinking density, a weighted quantity-frequency measure of alcohol consumption, was stronger among adults exposed to childhood maltreatment.

METHOD

Drinking density, stressful life events, and child maltreatment were assessed using structured clinical interviews in a sample of 4,038 male and female participants ages 20-58 years from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders. Stress sensitization was examined using hierarchical multiple regression analyses to test whether stressful events moderated the association between maltreatment and drinking density. Analyses were stratified by sex and whether the impact was different for independent stressful events or dependent stressful events as related to a participant's actions.

RESULTS

Independent stressful events were associated with heavier drinking density among women exposed to maltreatment. In contrast, drinking density was roughly the same across independent stressful life events exposure among women not exposed to maltreatment. There was little evidence for Maltreatment × Independent Stressor interactions in men or Maltreatment × Dependent Stressor interactions in either gender.

CONCLUSIONS

Early maltreatment may have direct effects on vulnerability to stress-related drinking among women, particularly in association with stressors that are out of one's control.