Trends in adolescent alcohol use: effects of age, sex and cohort on prevalence and heritability

Alcohol use among children and adolescents with chronic pain. Scoping review

AIM

To examine and map alcohol consumption in children and adolescents with chronic pain (CP).

METHOD

A scoping review of international databases (CINAHL, WOS, PubMed, PsycINFO, Scopus, Embase, and MEDLINE) and grey literature was conducted between September 2022 and February 2023. Documents addressing the relationship between alcohol consumption and CP in children and adolescents, published in English and Spanish between 2012 and 2023, were included. Those papers with a population suffering from CP derived from neurodegenerative diseases, chronic infectious diseases or cognitive impairment were excluded. We assessed the level of evidence (LE) and the degree of recommendation (DR) of the studies included in accordance with the Scottish Intercollegiate Guidelines Network. Finally, 11 documents were considered out of the 479 reviewed.

RESULTS

The relationship between substance consumption and CP in adolescents is a scarcely investigated topic. While there is a trend towards lower rates of alcohol consumption in youth with pain, there is evidence suggesting an association, particularly in cases of intense pain. The use of various substances, both legal and illegal, for pain management underscores the importance of comprehensively addressing this phenomenon in this population.

CONCLUSIONS

Further research is needed to assess the relationship between alcohol consumption in children and adolescents with CP.

Racial/ethnic discrimination, ADH1B*3, and coping-motivated drinking among Black college students

BACKGROUND AND OBJECTIVES

Discrimination due to race and/or ethnicity can be a pervasive stressor for Black college students in the United States beyond general negative life events and has demonstrated associations with adverse health and alcohol outcomes. Genetics may confer individual differences in the risk of drinking to cope with discrimination-related stress. This study tested whether associations of racial/ethnic discrimination with coping drinking motives and alcohol use differ as a function of a well-documented variant in the alcohol dehydrogenase 1B gene (ADH1B*3).

METHODS

Cross-sectional data were obtained from 241 Black students (Mage  = 20.04 [range = 18-53]; 66% female) attending a predominantly White university in the northeastern United States. Participants provided a saliva sample for genotyping and self-reported on their racial/ethnic discrimination experiences, coping drinking motives, and past-month total alcohol quantity.

RESULTS

Path models demonstrated that associations of discrimination with alcohol quantity directly or indirectly through coping drinking motives did not differ as a function of ADH1B*3, after controlling for gender, age, negative life events, and potential confounding interactions of covariates with model predictors. Regardless of ADH1B*3, greater experience of negative life events was associated with higher coping drinking motives, which in turn were associated with greater alcohol quantity. CONCLUSION AND SCIENTIFIC SIGNIFICANCE: Findings represent a novel investigation into gene-environment interplay in associations of alcohol use with racial/ethnic discrimination. Findings demonstrate coping-motivated drinking associated with negative life events within Black college drinkers regardless of ADH1B*3. Future research should leverage longitudinal designs to characterize associations of genetics, stressful experiences, and coping-motivated drinking over time.

Major depressive symptoms and escalation of drinking among new drinkers in the United States: Variations across sex and age groups

BACKGROUND

Heavy episodic drinking is common in the United States (US) and causes substantial burden to individuals and the society. The transition from first drinking to first heavy drinking episode is a major milestone in the escalation of drinking. There is limited evidence about whether major depressive symptoms predict the progression from drinking to heavy drinking and potential variations across age, sex, and depressive symptoms. In this study, we aim to estimate the association between history of major depressive symptoms and the risk of first heavy drinking episode among new drinkers in the US.

METHODS

Study population was US non-institutionalized civilian new drinkers 12 years of age and older who had their first drink during the past 12 months drawn from the National Survey on Drug Use and Health. History of major depressive symptoms and alcohol drinking behaviors were assessed via audio-computer-assisted self-interviews. Logistic regressions and structural equation modeling were used for analysis.

RESULTS

Depressed mood and/or anhedonia predicted the transition from the first drink to a heavy drinking episode among underage female new drinkers, whereas null associations were found among males and female new drinkers who had their first drink at 21 and later. Among new drinkers with depressed mood and/or anhedonia, low mood or energy positively predicted the progression to a heavy drinking episode among late-adolescent boys, but negatively among late-adolescent girls; neurovegetative symptoms positively predicted the progression to a heavy drinking episode among young adult new drinkers.

CONCLUSIONS

The relationships linking major depressive symptoms and the transition from drinking to first heavy drinking episode vary across age, sex, and depressive symptoms.

Heritability of ethanol consumption and pharmacokinetics in a genetically diverse panel of collaborative cross mouse strains and their inbred founders

BACKGROUND

Interindividual variation in voluntary ethanol consumption and ethanol response is partially influenced by genetic variation. Discovery of the genes and allelic variants that affect these phenotypes may clarify the etiology and pathophysiology of problematic alcohol use, including alcohol use disorder. Genetically diverse mouse populations, which demonstrate heritable variation in ethanol consumption, can be utilized to discover the genes and gene networks that influence this trait. The Collaborative Cross (CC) recombinant inbred strains, Diversity Outbred (DO) population and their 8 founder strains are complementary mouse resources that capture substantial genetic diversity and can demonstrate expansive phenotypic variation in heritable traits. These populations may be utilized to discover candidate genes and gene networks that moderate ethanol consumption and other ethanol-related traits.

METHODS

We characterized ethanol consumption, preference, and pharmacokinetics in the 8 founder strains and 10 CC strains in 12-hour drinking sessions during the dark phase of the circadian cycle.

RESULTS

Ethanol consumption was substantially heritable, both early in ethanol access and over a chronic intermittent access schedule. Ethanol pharmacokinetics were also heritable; however, no association between strain-level ethanol consumption and pharmacokinetics was detected. The PWK/PhJ strain was the highest drinking strain, with consumption substantially exceeding that of the C57BL/6J strain, which is commonly used as a model of "high" or "binge" drinking. Notably, we found strong evidence that sex moderated genetic effects on voluntary ethanol drinking.

CONCLUSIONS

Collectively, this research serves as a foundation for expanded genetic study of ethanol consumption in the CC/DO and related populations. Moreover, we identified reference strains with extreme consumption phenotypes that effectively represent polygenic models of excessive ethanol use.

Adolescent Intermittent Ethanol Exposure Effects on Kappa Opioid Receptor Mediated Dopamine Transmission: Sex and Age of Exposure Matter

Underage alcohol drinking increases the risk of developing alcohol use disorder (AUD). In rodents, adolescent ethanol exposure augments ethanol consumption and anxiety-like behavior while reducing social interaction. However, the underlying mechanisms driving these adaptations are unclear. The dopamine and kappa opioid receptor (KOR) systems in the nucleus accumbens (NAc) are implicated in affective disorders, including AUD, with studies showing augmented KOR function and reduced dopamine transmission in ethanol-dependent adult animals. Thus, here we examine the impact of adolescent intermittent ethanol (AIE) exposure on dopamine transmission and KOR function in the NAc. Rats were exposed to water or ethanol (4 g/kg, intragastrically) every other day during early (postnatal day (PD) 25–45) or late (PD 45–65) adolescence. While AIE exposure during early adolescence (early-AIE) did not alter dopamine release in male and female rats, AIE exposure during late adolescence (late-AIE) resulted in greater dopamine release in males and lower dopamine release in females. To determine the impact of AIE on KOR function, we measured the effect of KOR activation using U50,488 (0.01–1.00 µM) on dopamine release. Early-AIE exposure potentiated KOR-mediated inhibition of dopamine release in females, while late-AIE exposure attenuated this effect in males. Interestingly, no differences in KOR function were observed in early-AIE exposed males and late-AIE exposed females. Together, these data suggest that AIE exposure impact on neural processes is dependent on sex and exposure timing. These differences likely arise from differential developmental timing in males and females. This is the first study to show changes in KOR function following AIE exposure.

Exploring how Family and Neighborhood Stressors Influence Genetic Risk for Adolescent Conduct Problems and Alcohol Use

Previous research suggests that genetic risk factors may predispose to conduct problems and alcohol use in adolescence. Whether genetic risk factors interact with social contexts has not been well characterized among African American adolescents. Data came from a subsample of the Genes, Environment, and Neighborhood Initiative study comprising 501 African American adolescents, including 151 lifetime drinkers (56% female, mean age = 16.3, SD = 1.4). Genetic risk was assessed with polygenic risk scores for alcohol dependence. Analyses explored interactions between genetic risk and self-reported alcohol use, conduct problems, life stressors, and other covariates. The effects of two gene-environment interactions (G × E) were tested in the sample of alcohol exposed adolescents; one on conduct problems and the other on alcohol use. There were significant associations between polygenic risk for alcohol dependence and conduct problems. A significant G × E interaction showed the impact of genetic risk on conduct problems was stronger under conditions of high exposure to family and neighborhood stressors. Among this sample of African American adolescents, genetic risk for alcohol dependence was not directly associated with alcohol use but was related to more conduct problems. Further, the effect of genetic risk interacted with stressors from the family and neighborhood, so that the effect of genetic risk on conduct problems was stronger for individuals who reported greater stressors.

Genetic and environmental influences on developmental trajectories of adolescent alcohol use

Adolescent alcohol use demonstrates distinct developmental trajectories with different times of onset, levels, and rates of growth. Twin research on adolescent alcohol use has shown that genetic influences are consistent with a gradual growth of risks, whereas non-shared environmental influences are more consistent with an accumulation of risks over time. The current study investigated the relative contributions of genetic and environmental influences on shaping different developmental trajectories of alcohol use through adolescence. Self-reported past year alcohol use was collected from 877 Canadian twins (47.1% males) at age 13, 14, 15, and 17 years. Growth mixture models were fit to examine different developmental trajectories of alcohol use, and biometric liability threshold models were fit to investigate genetic and environmental influences on the liability of belonging to identified trajectories. Three trajectories were identified: low (15.1%), early onset (8.2%), and normative increasing (76.7%). Memberships in the low and early-onset group were under genetic (27.6% and 34.7%), shared (42.4% and 21.5%), and non-shared environment influences (30.0% and 43.8%). Membership in the normative increasing group was under genetic (37.7%) and non-shared environment influences (62.3%). Non-shared environmental influences were significantly larger for the normative increasing trajectory than for the low trajectory. These findings provide a more refined picture of genetic and environmental influences in the development of alcohol use in subgroups of adolescents. Genetic and environmental influences both matter, but to different degrees in different trajectories. Future research should identify specific shared and non-shared environmental experiences that distinguish different trajectories.

Birth cohort effects on the quantity and heritability of alcohol consumption in adulthood: a Finnish longitudinal twin study

AIMS

To estimate birth cohort effects on alcohol consumption and abstinence in Finland and to test differences between birth cohorts in genetic and environmental sources of variation in Finnish adult alcohol use.

DESIGN

The Older Finnish Twin Cohort longitudinal survey study 1975-2011.

SETTING

Finland.

PARTICIPANTS

A total of 26 121 same-sex twins aged 18-95 years (full twin pairs at baseline n = 11 608).

MEASUREMENTS

Outcome variables were the quantity of alcohol consumption (g/month) and abstinence (drinking zero g/month). Predictor variables were 10-year birth cohort categories and socio-demographic covariates. In quantitative genetic models, two larger cohorts (born 1901-20 and 1945-57) were compared.

FINDINGS

Multi-level models in both sexes indicated higher levels of alcohol consumption in more recent birth cohorts and lower levels in earlier cohorts, compared with twins born 1921-30 (all P < 0.003). Similarly, compared with twins born 1921-30, abstaining was more common in earlier and less common in more recent cohorts (all P < 0.05), with the exception of men born 1911-20. Birth cohort differences in the genetic and environmental variance components in alcohol consumption were found: heritability was 21% [95% confidence interval (CI) = 0-56%] in the earlier-born cohort of women [mean age 62.8, standard deviation (SD) = 5.3] and 51% (95% CI = 36-56%) in a more recent cohort (mean age 60.2, SD = 3.7) at the age of 54-74. For men, heritability was 39% (95% CI = 27-45%) in both cohorts. In alcohol abstinence, environmental influences shared between co-twins explained a large proportion of variation in the earlier-born cohort (43%, 95% CI = 23-63%), whereas non-shared environmental (54%, 95% CI = 39-72%) and additive genetic influences (40%, 95% CI = 13-61%) were more important among more recent cohorts of men and women.

CONCLUSION

The contribution of genetic and environmental variability to variability in alcohol consumption in the Finnish population appears to vary by birth cohort.

The Relationship Between Pain Severity and Alcohol Use Among School-Aged Children and Adolescents: The Moderating Role of Drinking Motives

Objective

Evidence from adult samples suggests a co-occurrence between pain and alcohol abuse. However, studies in adolescents are scarce and results are inconsistent, with some studies observing heightened and others observing reduced alcohol consumption in adolescents suffering from pain. We hypothesized that in adolescents the association between pain and alcohol use will be moderated by drinking motives.

Methods

Data from a large representative sample of Flemish school children and adolescents (N = 10,650, 50.8% boys, age range = 10-21 years, Mage = 14.33 years) were collected as part of the World Health Organization collaborative Health Behaviour in School-Aged Children (HBSC) survey. Pain severity was graded based on a pediatric pain classification system that accounts for both pain intensity and disability. Alcohol consumption was operationalized using two variables: frequency of drinking and drunkenness. The Drinking Motives Questionnaire-Revised was used to capture drinking motives; it assesses four motive categories (enhancement, coping, social, and conformity).

Results

Findings indicated that higher pain severity was associated with greater frequency of alcohol use and drunkenness. However, drinking motives moderated this association. The positive association between pain severity and drinking frequency was stronger in case of high conformity motives. Likewise, the association between pain severity and drunkenness frequency was stronger at high levels of conformity motives and reached significance only at high levels of coping motives.

Conclusions

Our findings suggest that specific drinking motives are linked to problematic alcohol use in adolescents with pain. Future studies using a longitudinal design are needed to draw conclusions about direction of effects.

A systematic review: Candidate gene and environment interaction on alcohol use and misuse among adolescents and young adults

BACKGROUND AND OBJECTIVES

Youth drinking is a pervasive public health concern with serious negative developmental implications. Candidate gene and environment interaction studies (cGxE) show that environmental effects on drinking behaviors may differ by individuals' genotypes. Yet little is known about whether genetic and environmental effects on drinking behaviors are developmentally specific.

METHODS

This systematic review evaluated 42 cGxE studies of drinking in adolescence and young adulthood.

RESULTS

Although there are mixed findings, studies of cGxE effects involving DRD4, 5-HTTLPR, DRD2, and OPRM1 genotypes showed relatively consistent patterns. The effects of under-controlled environments (eg, low levels of parental monitoring) on early and middle adolescent drinking appeared to differ across DRD2 or OPRM1 genotypes. Effects of alcohol-facilitating environments (eg, heavy drinking peers) on late adolescent and young adult drinking appeared to differ across DRD4 or OPRM1 genotypes. Interactions between 5-HTTLPR genotype with stressful environments (eg, negative life events) were found throughout adolescence and young adulthood, although there were some inconsistencies regarding the risk-conferring allele. There was limited evidence for other cGxE effects due to the small number of studies.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

This review suggests that GxE findings may advance our knowledge regarding which developmentally specific conditions result in the expression of candidate genes that influence youth alcohol use and misuse. However, since a significant number of studies had small sample sizes and most studies had small effect sizes, findings need replication across independent studies with large samples. (Am J Addict 2018;XX:1-19).

Shared familial risk between bulimic symptoms and alcohol involvement during adolescence

Twin studies show the established relation between bulimic symptoms and problematic alcohol involvement in adult females is partly due to shared familial factors, specifically shared genetic effects. However, it is unclear if similar shared etiological factors exist during adolescence or in males. We examined the familial overlap (i.e., genetic and common environmental correlations) between bulimic symptoms and various levels of alcohol involvement in 16- to 17-year-old female and male same-sex twin pairs using sex-specific biometrical twin modeling. Bulimic symptoms were assessed with the Eating Disorder Inventory-2. Alcohol involvement included alcohol use in the last month, having ever been intoxicated, and alcohol intoxication frequency. Results revealed 3 distinct patterns. First, in general, phenotypic correlations indicated statistically similar associations between bulimic symptoms and alcohol involvement in girls and boys. Second, common environmental overlap was significant for the bivariate associations including having ever been intoxicated. Third, moderate genetic correlations were observed between all bulimic symptoms and alcohol involvement in girls and moderate common environmental correlations were observed in boys for the more risky/deviant levels of involvement. Similar to adults, there is familial overlap between bulimic symptoms and alcohol involvement in adolescent girls and boys. These results could inform symptom- and sex-specific, developmentally targeted prevention and intervention programs for the comorbidity between bulimic symptoms and alcohol involvement. (PsycINFO Database Record

Interaction between ADH1B*3 and alcohol-facilitating social environments in alcohol behaviors among college students of african descent

BACKGROUND AND OBJECTIVES

Although alcohol-facilitating social environmental factors, such as alcohol offers and high perceived peer drinking norms, have been extensively studied as determinants of college drinking, their role among college students of African descent remains understudied. Furthermore, gene-environment interaction research suggests that the effects of alcohol-facilitating environments may differ as a function of genetic factors. Specifically, the alcohol dehydrogenase gene's ADH1B*3 allele, found almost exclusively in persons of African descent, may modulate the association of risky social environments with alcohol behaviors. The current study examined whether the ADH1B*3 allele attenuated the relationship between alcohol-facilitating environments (ie, alcohol offers and perceived peer drinking norms) and alcohol behaviors.

METHOD

Participants were 241 undergraduate students who self-identified as being of African descent (mean age = 20 years [SD = 4.11]; 66% female).

RESULTS

Significant interaction effects of ADH1B*3 with alcohol offers were found on alcohol use frequency (incidence rate ratio [IRR] = 1.14) and on drinking consequences (IRR = 1.21). ADH1B*3 also interacted with perceived peer norms on drinking consequences (IRR = 1.41). Carriers of the ADH1B*3 allele drank less frequently and experienced fewer negative consequences than non-carriers when exposed to lower levels of alcohol offers and perceived peer drinking. In contrast, in high alcohol-facilitating environments, no protective genetic effect was observed.

DISCUSSION AND CONCLUSION

This study demonstrates that ADH1B*3 may protect college students of African descent against alcohol outcomes, although only in low alcohol-facilitating environments.

SCIENTIFIC SIGNIFICANCE

Findings add to the growing body of knowledge regarding genetic and social determinants of alcohol behaviors among college students of African descent. (Am J Addict 2017;26:349-356).

The natural history of risky drinking and associated harms from adolescence to young adulthood: findings from the Australian Temperament Project

BACKGROUND

We aimed to describe the natural history of heavy episodic drinking (HED) and associated harms from adolescence to young adulthood in a large Australian population cohort study.

METHOD

The Australian Temperament Project consists of mothers and babies (4-8 months) recruited from Infant Welfare Centres and followed every 2 to 4 years until age 28 years. Analyses were based on data from 1156 young people (497 male; 659 female) surveyed repeatedly at ages 16, 18, 20, 24 and 28 years. We used dual processes latent class growth analysis to estimate trajectories of HED and associated harms, employing a piecewise approach to model the hypothesized rise and subsequent fall across adolescence and the late twenties, respectively.

RESULTS

We identified four sex-specific trajectories and observed little evidence of maturing-out across the twenties. In males, a normative pattern of increasing HED across the twenties with little related harm was observed (40% of the male sample). Early and late starter groups that peaked in harms at age 20 years with only minor attenuation in binging thereafter were also observed (6.1% and 35%, respectively). In females, a normative pattern of increasing, but moderate, HED with little related harm was observed (44% of the female sample). Early and late starter groups were also identified (18% and 17%, respectively); however, unlike males, the female late starter group showed a pattern of increasing HED and related harms.

CONCLUSIONS

Continued patterns of risky alcohol use and related harms are apparent for both males and females across the twenties.

Alcohol-Related Posts from Young People on Social Networking Sites: Content and Motivations

Many young people place alcohol-related posts on social networking sites (SNS) which can result in undesirable effects. Although several recent studies have investigated the occurrence of alcohol-related SNS use, it is neither clear (a) what type of alcohol posts are placed on SNS, (b) the motivations to place alcohol posts, nor (c) which young people are most likely to place alcohol posts. This study addressed these three goals. A large cross-sectional study among young participants (12-30 years; N = 561) assessed the posting of different types of alcohol posts, the motivations to (not) post these posts, and potential differences in posting between subgroups (i.e., in terms of age, gender, and religion). Participants reported that they most often placed moderate, instead of more extreme, alcohol posts, in particular, when alcohol was present in the post "by chance". Furthermore, they indicated to post alcohol-related content mostly for entertainment reasons. Finally, we found differences in self-reported posting and motivations to post according to age, gender, and religion. These findings provide relevant implications for future interventions aiming to decrease alcohol posts, for example, by making participants aware of their posting behavior and by targeting specific at risk groups. Future research should explore the effectiveness of such intervention strategies and should investigate whether alcohol posts lead to an underestimation of alcohol-related risks.

Genetic and environmental sources of covariation between early drinking and adult functioning

The vast majority of individuals initiate alcohol consumption for the first time in adolescence. Given the widespread nature of its use and evidence that adolescents may be especially vulnerable to its effects, there is concern about the long-term detrimental impact of adolescent drinking on adult functioning. While some researchers have suggested that genetic processes may confound the relationship, the mechanisms linking drinking and later adjustment remain unclear. The current study utilized a genetically informed sample and biometric modeling to examine the nature of the familial influences on this association and identify the potential for genetic confounding. The sample was drawn from the Minnesota Twin Family Study (MTFS), a longitudinal study consisting of 2,764 twins assessed in 2 cohorts at regular follow-ups from age 17 to age 29 (older cohort) or age 11 to age 29 (younger cohort). A broad range of adult measures was included assessing substance use, antisocial behavior, personality, socioeconomic status, and social functioning. A bivariate Cholesky decomposition was used to examine the common genetic and environmental influences on adolescent drinking and each of the measures of adult adjustment. The results revealed that genetic factors and nonshared environmental influences were generally most important in explaining the relationship between adolescent drinking and later functioning. While the presence of nonshared environmental influences on the association are not inconsistent with a causal impact of adolescent drinking, the findings suggest that many of the adjustment issues associated with adolescent alcohol consumption are best understood as genetically influenced vulnerabilities. (PsycINFO Database Record

The Rate of Change in Alcohol Misuse Across Adolescence is Heritable

BACKGROUND

Alcohol use typically begins during adolescence and escalates into young adulthood. This represents an important period for the establishment of alcohol use and misuse patterns, which can have psychosocial and medical consequences. Although changes in alcohol use during this time have been phenotypically characterized, their genetic nature is poorly understood.

METHODS

Participants of the Avon Longitudinal Study of Parents and Children completed the Alcohol Use Disorders Identification Test (AUDIT) 4 times from age 16 to 20. We used Mplus to construct a growth model characterizing changes in AUDIT scores across time (N = 4,545, where data were available for at least 2 time points). The slope of the model was used as the phenotype in a genomewide association study (N = 3,380), followed by secondary genetic analyses.

RESULTS

No individual marker met genomewide significance criteria. Top markers mapped to biologically plausible candidate genes. The slope term was moderately heritable (h²_SNP = 0.26, p = 0.009), and replication attempts using a meta-analysis of independent samples provided support for implicated variants at the aggregate level. Nominally significant (p < 0.00001) markers mapped to putatively active genomic regions in brain tissue more frequently than expected by chance.

CONCLUSIONS

These results build on prior studies by demonstrating that common genetic variation impacts alcohol misuse trajectories. Influential loci map to genes that merit additional research, as well as to intergenic regions with regulatory functions in the central nervous system. These findings underscore the complex biological nature of alcohol misuse across development.

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.

Heritability of compulsive Internet use in adolescents

Over the past decades, Internet use has grown substantially, and it now serves people as a supportive tool that is used regularly and—in large parts of the world—inevitably. Some people develop problematic Internet use, which may lead to addictive behavior and it is becoming important to explore the risk factors for compulsive Internet use. Data were analyzed on compulsive Internet use [with the Compulsive Internet Use Scale (CIUS)] from 5247 monozygotic (MZ) and dizygotic (DZ) adolescent twins registered with the Netherlands Twin Register. The participants form a sample that is informative for genetic analyses, allowing the investigation of the causes of individual differences in compulsive Internet use. The internal consistency of the instrument was high and the 1.6‐year test–retest correlation in a subsample (n = 902) was 0.55. CIUS scores increased slightly with age. Remarkably, gender did not explain variation in CIUS scores, as mean scores on the CIUS were the same in boys and girls. However, the time spent on specific Internet activities differed: boys spent more time on gaming, whereas girls spent more time on social network sites and chatting. The heritability estimates were the same for boys and girls: 48 percent of the individual differences in CIUS score were influenced by genetic factors. The remaining variance (52 percent) was due to environmental influences that were not shared between family members. Because a life without Internet is almost impossible nowadays, it is important to further explore the determinants of compulsive Internet use, including genetic risk factors.

Changing the conversation: the influence of emotions on conversational valence and alcohol consumption

Health campaign effects may be improved by taking interpersonal communication processes into account. The current study, which employed an experimental, pretest-posttest, randomized exposure design (N = 208), investigated whether the emotions induced by anti-alcohol messages influence conversational valence about alcohol and subsequent persuasion outcomes. The study produced three main findings. First, an increase in the emotion fear induced a negative conversational valence about alcohol. Second, fear was most strongly induced by a disgusting message, whereas a humorous appeal induced the least fear. Third, a negative conversational valence elicited healthier binge drinking attitudes, subjective norms, perceived behavioral control, intentions, and behaviors. Thus, health campaign planners and health researchers should pay special attention to the emotional characteristics of health messages and should focus on inducing a healthy conversational valence.

Genetic and environmental influences on the ages of drinking and gambling initiation: evidence for distinct aetiologies and sex differences

AIMS

To investigate the genetic and environmental contributions to age at first drink (AFD) and age first gambled (AFG), assess their overlap and examine sex differences.

DESIGN

Univariate twin models were fitted to decompose the variation in AFD and AFG into additive genetic, shared environmental and unique environmental factors. Bivariate genetic models were fitted to assess the genetic and environmental contributions to the sources of covariation in AFD and AFG.

SETTING

National Australian Twin Registry.

PARTICIPANTS

A total of 4542 same-sex and opposite-sex twins aged 32-43 years, 42% male and 58% female.

MEASUREMENTS

AFD and AFG were assessed via structured psychiatric telephone interviews. Age of onset was treated as both continuous and categorical (early/late onset).

FINDINGS

AFD and AFG were modestly correlated (r = 0.18). Unique environmental influences explained a substantial proportion of the variation in both AFD (0.55, 95% confidence interval [CI] = 0.50-0.61) and AFG (0.66, 95% CI = 0.59-0.72), but these influences were uncorrelated (rE  = 0.01). Additive genetic factors explained a notable proportion of variation in AFG (0.21, 95% CI = 0.003-0.39), while shared environmental factors were important for AFD (0.31, 95% CI = 0.15-0.46). Among men, genetic factors influenced variation in AFG but not in AFD and shared environmental factors influenced variation in AFD but not in AFG. Among women, shared environmental factors influenced variation in both AFD and AFG, but these environmental factors were not significantly correlated (rC  = 0.09).

CONCLUSIONS

Among Australian twins, age at first drink and age first gambled are influenced by distinct unique environmental factors, and the genetic and environmental underpinnings of both phenotypes differ in men and women.

Academic achievement as a moderator of genetic influences on alcohol use in adolescence

Prior research suggests a link between academic performance and alcohol use during adolescence, but the degree to which this association reflects actual protective effects continues to be debated. We investigated the role of genetic factors in the association between academic achievement and adolescent alcohol use and whether achievement might constrain the translation of genetic influences on drinking into actual behavior (a Gene × Environment interaction). Analysis of twin data from Add Health (n = 399 monozygotic and dizygotic twin pairs) revealed not only common genetic factors underlying the association between achievement and alcohol consumption but also evidence for a gene-environment interaction. Specifically, the protective effect of achievement operated by moderating heritability of alcohol use, which was particularly salient for adolescents at high genetic risk for alcohol use.

Alcohol consumption in men is influenced by qualitatively different genetic factors in adolescence and adulthood

BACKGROUND

Alcohol consumption is influenced by genetic factors. Previous studies have examined the heritability of alcohol consumption, or related phenotypes, from adolescence into adulthood, frequently finding that total heritability changes over time. However, it remains unclear whether the same genes underlie liability to alcohol consumption across development versus whether novel risk genes become important over time. Method A population-based study of adult male twins (n=1790) born in Virginia, USA, retrospectively reported on their average monthly alcohol consumption from early adolescence through adulthood. We used twin modeling methods to explore genetic and environmental influences on alcohol consumption over time.

RESULTS

One latent genetic factor accounted for the majority of the heritability in alcohol consumption during mid- to late adolescence, but its influence declined thereafter; from young adulthood forward, heritability was largely attributable to a second genetic factor. The total heritability of alcohol consumption increased from 0 at ages 12-14 years to 0.40 by ages 18-21 years. Shared environmental factors declined in influence over time.

CONCLUSIONS

The heritability of alcohol consumption over time is dynamic both quantitatively and qualitatively. These results have important implications for gene identification endeavors. Furthermore, these findings could inform efforts to elucidate developmentally dynamic behaviors, such as antisocial behavior.

Increases in alcohol consumption in women and elderly groups: evidence from an epidemiological study

BACKGROUND

In most Western countries, alcohol consumption continues to increase, specifically among women and older adults. Insight into these trends may aid intervention strategies. Here we present data on alcohol consumption by age and sex as well as associations between alcohol use and demographic lifestyle/traits. The data are from a large (N>16,000) population-based Dutch sample, ascertained based on the presence of twins in the family.

METHODS

A set of 16 indicators of normative and problematic alcohol use was assessed in participants of the Netherlands Twin Register between 2009-2012 (ages 18-97; 6,052 men; 10,535 women). Alcohol consumption and demographic/lifestyle traits, including educational attainment, work-related/financial stress, urbanization, religiousness, smoking/cannabis initiation, and BMI were described by age and sex. Associations were examined by regressing aspects of alcohol use on age, sex, their interaction, and demographic/lifestyle variables.

RESULTS

Age, sex, and initiation of cigarette and cannabis use were the most important predictors of alcohol use. Frequency of alcohol use was lowest between 18-25 years, with 3.2% of men and .6% of women drinking 6-7 times/week, and highest above age 65 years, with 30.6-32.7% of men and 20.2-22.0% of women drinking 6-7 times/week. Women consumed the lowest quantities of alcohol between 25-45 years, with a 5.7-5.9% prevalence of excessive drinking (>14 glasses/week), and the largest quantities between 55-65 years (15.5% excessive drinkers). Age at alcohol initiation, onset of regular drinking, and first alcohol intoxication were lowest between ages 18-25 years and highest above age 65 years. Among older participants, men initiated alcohol use and regular drinking earlier, and had lower age at first intoxication than women, but among young adults, no sex differences were observed.

CONCLUSIONS

Alcohol consumption was high in the elderly Dutch population, especially among women. Alcohol initiation, onset of regular drinking, and first alcohol intoxication occur at increasingly younger ages, and the previous gap between men and women in age at alcohol initiation, onset of regular drinking, and first alcohol intoxication has closed almost entirely. Heavy alcohol use was most strongly predicted by older age, sex (male), and initiation of smoking and cannabis use.

The effectiveness of the 'what do you drink' web-based brief alcohol intervention in reducing heavy drinking among students: a two-arm parallel group randomized controlled trial

AIMS

To evaluate the effectiveness of a web-based brief alcohol intervention 'What Do You Drink' (WDYD) among heavy drinking students at 1- and 6-month post-intervention. Additionally, it was investigated whether certain subgroups would benefit more than others from the WDYD intervention.

METHODS

A two-arm parallel group randomized controlled trial was conducted online in the Netherlands in 2010-2011. Inclusion criteria were: (1) being between 18- and 24-year old, (2) reporting heavy drinking in the past 6 months, (3) being motivated to change alcohol consumption, (4) having access to the Internet and (5) giving informed consent. Participants (n = 913) were randomized to the experimental (WDYD intervention) or control condition (no intervention). Measures were heavy drinking, frequency of binge drinking and weekly alcohol consumption.

RESULTS

Analyses according to the intention-to-treat principle revealed no significant main intervention effects in reducing the alcohol measures at the follow-up assessments. Secondary analyses revealed that gender, freshmen and fraternity or sorority membership did not moderate the effect of the WDYD intervention at both follow-ups. Readiness to change, problem drinking and carnival participation moderated intervention effects such that contemplators, those with severe symptoms of alcohol abuse or dependence, and those who participated in carnival benefited more than others from the WDYD intervention regarding weekly alcohol consumption at 1-month follow-up.

CONCLUSIONS

The WDYD intervention was not effective in reducing the alcohol measures among heavy drinking students at 1- and 6-month post-intervention. However, there is preliminary evidence that the WDYD intervention is effective in lowering drinking levels for subgroups of heavy drinking students in the short term.

The Young Netherlands Twin Register (YNTR): longitudinal twin and family studies in over 70,000 children

The Netherlands Twin Register (NTR) began in 1987 with data collection in twins and their families, including families with newborn twins and triplets. Twenty-five years later, the NTR has collected at least one survey for 70,784 children, born after 1985. For the majority of twins, longitudinal data collection has been done by age-specific surveys. Shortly after giving birth, mothers receive a first survey with items on pregnancy and birth. At age 2, a survey on growth and achievement of milestones is sent. At ages 3, 7, 9/10, and 12 parents and teachers receive a series of surveys that are targeted at the development of emotional and behavior problems. From age 14 years onward, adolescent twins and their siblings report on their behavior problems, health, and lifestyle. When the twins are 18 years and older, parents are also invited to take part in survey studies. In sub-groups of different ages, in-depth phenotyping was done for IQ, electroencephalography , MRI, growth, hormones, neuropsychological assessments, and cardiovascular measures. DNA and biological samples have also been collected and large numbers of twin pairs and parents have been genotyped for zygosity by either micro-satellites or sets of short nucleotide polymorphisms and repeat polymorphisms in candidate genes. Subject recruitment and data collection is still ongoing and the longitudinal database is growing. Data collection by record linkage in the Netherlands is beginning and we expect these combined longitudinal data to provide increased insights into the genetic etiology of development of mental and physical health in children and adolescents.

Impact of lifestyle and technology developments on sleep

Although the physiological and psychological mechanisms involved in the development of sleep disorders remain similar throughout history, factors that potentiate these mechanisms are closely related to the "zeitgeist", ie, the sociocultural, technological and lifestyle trends which characterize an era. Technological advancements have afforded modern society with 24-hour work operations, transmeridian travel and exposure to a myriad of electronic devices such as televisions, computers and cellular phones. Growing evidence suggests that these advancements take their toll on human functioning and health via their damaging effects on sleep quality, quantity and timing. Additional behavioral lifestyle factors associated with poor sleep include weight gain, insufficient physical exercise and consumption of substances such as caffeine, alcohol and nicotine. Some of these factors have been implicated as self-help aids used to combat daytime sleepiness and impaired daytime functioning. This review aims to highlight current lifestyle trends that have been shown in scientific investigations to be associated with sleep patterns, sleep duration and sleep quality. Current understanding of the underlying mechanisms of these associations will be presented, as well as some of the reported consequences. Available therapies used to treat some lifestyle related sleep disorders will be discussed. Perspectives will be provided for further investigation of lifestyle factors that are associated with poor sleep, including developing theoretical frameworks, identifying underlying mechanisms, and establishing appropriate therapies and public health interventions aimed to improve sleep behaviors in order to enhance functioning and health in modern society.

Stable genetic effects on symptoms of alcohol abuse and dependence from adolescence into early adulthood

Relatively little is known about how genetic influences on alcohol abuse and dependence (AAD) change with age. We examined the change in influence of genetic and environmental factors which explain symptoms of AAD from adolescence into early adulthood. Symptoms of AAD were assessed using the four AAD screening questions of the CAGE inventory. Data were obtained up to six times by self-report questionnaires for 8,398 twins from the Netherlands Twin Register aged between 15 and 32 years. Longitudinal genetic simplex modeling was performed with Mx. Results showed that shared environmental influences were present for age 15-17 (57%) and age 18-20 (18%). Unique environmental influences gained importance over time, contributing 15% of the variance at age 15-17 and 48% at age 30-32. At younger ages, unique environmental influences were largely age-specific, while at later ages, age-specific influences became less important. Genetic influences on AAD symptoms over age could be accounted for by one factor, with the relative influence of this factor differing across ages. Genetic influences increased from 28% at age 15-17 to 58% at age 21-23 and remained high in magnitude thereafter. These results are in line with a developmentally stable hypothesis that predicts that a single set of genetic risk factors acts on symptoms of AAD from adolescence into young adulthood.