Searching for an environmental effect of parental alcoholism on offspring alcohol use disorder: a genetically informed study of children of alcoholics

The collaborative study on the genetics of alcoholism: Genetics

This review describes the genetic approaches and results from the family-based Collaborative Study on the Genetics of Alcoholism (COGA). COGA was designed during the linkage era to identify genes affecting the risk for alcohol use disorder (AUD) and related problems, and was among the first AUD-focused studies to subsequently adopt a genome-wide association (GWAS) approach. COGA's family-based structure, multimodal assessment with gold-standard clinical and neurophysiological data, and the availability of prospective longitudinal phenotyping continues to provide insights into the etiology of AUD and related disorders. These include investigations of genetic risk and trajectories of substance use and use disorders, phenome-wide association studies of loci of interest, and investigations of pleiotropy, social genomics, genetic nurture, and within-family comparisons. COGA is one of the few AUD genetics projects that includes a substantial number of participants of African ancestry. The sharing of data and biospecimens has been a cornerstone of the COGA project, and COGA is a key contributor to large-scale GWAS consortia. COGA's wealth of publicly available genetic and extensive phenotyping data continues to provide a unique and adaptable resource for our understanding of the genetic etiology of AUD and related traits.

The relevant research of adverse childhood experiences and "risky drinking" in children of alcoholics in China

OBJECTIVE

To determine whether adverse childhood experiences (ACEs) of children of alcoholics (COA) in male were associated with their current "risky drinking".

METHODS

This case-control study used the Alcohol Use Disorder Identification Test (AUDIT, cutoff is 7) to divide the participants into two groups, a "risky drinking" group (N = 53) and a "non-risky drinking" group (N = 97). Demographic data, Adverse Childhood Experiences-International Questionnaire (ACE-IQ), the Hamilton Anxiety Rating Scale (HAMA), the Hamilton Depression Rating Scale (HAMD) and the Mini-International Neuropsychiatric Interview (MINI) were used for assessment. The specific relationships between ACEs and "risky drinking" were explored.

RESULTS

Respondents ranged in age from 29.70 ± 6.72 years; 74.5% were females; 94.7% were of Han nationality; 56.7% had a level of education above high school; 12% had no formal or stable job. There was difference in attitude to self-drinking between two groups (P < 0.001). The "risky drinking" group was more likely to have experienced a major depressive episode (P < 0.05), nonalcohol psychoactive substance use disorder (P < 0.01) and bulimia nervosa (P < 0.05), and they also experienced more physical abuse (P < 0.05), community violence (P < 0.001) and collective violence (P < 0.01). In a single factor logistic regression, physical abuse, community violence and collective violence were associated with a two to 11- fold increase in "risky drinking" in the adult COA, and in multiple factor logistic regression, community violence showed a graded relationship with "risky drinking".

CONCLUSION

The childhood adverse experiences contribute to "risky drinking" in COA. This finding in the Chinese context have significant implications for prevention not only in China but in other cultures. There must be greater awareness of the role of ACEs in the perpetuation of alcoholism.

Testing the specificity of environmental risk factors for developmental outcomes

Developmental theories often assume that specific environmental risks affect specific outcomes. Canonical Correlation Analysis was used to test whether 28 developmental outcomes (measured at 11-15 years) share the same early environmental risk factors (measured at 0-3 years), or whether specific outcomes are associated with specific risks. We used data from the UK Millennium Cohort Study (N = 10,376, 51% Female, 84% White) collected between 2001 and 2016. A single environment component was mostly sufficient for explaining cognition and parent-rated behavior outcomes. In contrast, adolescents' alcohol and tobacco use were specifically associated with their parents', and child-rated mental health was weakly associated with all risks. These findings suggest that with some exceptions, many different developmental outcomes share the same early environmental risk factors.

Association of parental substance misuse with offspring substance misuse and criminality: a genetically informed register-based study

BACKGROUND

Genetically informed studies have provided mixed findings as to what extent parental substance misuse is associated with offspring substance misuse and antisocial behavior due to shared environmental and genetic factors.

METHODS

We linked data from nationwide registries for a cohort of 2 476 198 offspring born in Sweden 1958-1995 and their parents. Substance misuse was defined as International Classification of Diseases diagnoses of alcohol/drug use disorders or alcohol/drug-related criminal convictions. Quantitative genetic offspring-of-siblings analyses in offspring of monozygotic and dizygotic twin, full-sibling, and half-sibling parents were conducted.

RESULTS

Both maternal and paternal substance misuse were robustly associated with offspring substance misuse [maternal adjusted hazard ratio (aHR) = 1.83 (95% confidence interval (CI) 1.80-1.87); paternal aHR = 1.96 (1.94-1.98)] and criminal convictions [maternal aHR = 1.56 (1.54-1.58); paternal aHR = 1.66 (1.64-1.67)]. Additive genetic effects explained 42% (95% CI 25-56%) and 46% (36-55%) of the variance in maternal and paternal substance misuse, respectively, and between 36 and 44% of the variance in substance misuse and criminality in offspring. The associations between parental substance misuse and offspring outcomes were mostly due to additive genetic effects, which explained 54-85% of the parent-offspring covariance. However, both nuclear and extended family environmental factors also contributed to the associations, especially with offspring substance misuse.

CONCLUSIONS

Our findings from a large offspring-of-siblings study indicate that shared genetic influences mostly explain the associations between parental substance misuse and both offspring substance misuse and criminality, but we also found evidence for the contribution of environmental factors shared by members of nuclear and extended families.

Problematic alcohol use in Mexican students: Transmission from parents to children

Introduction. Studies in various countries have shown that adolescents with a history of parental use of alcohol have a greater risk of presenting alcohol problems of their own, including binge drinking, driving under the influence of alcohol, and alcohol dependence. A few studies in Mexico have also found this association, but these have been carried out with non-representative populations. Objective. To examine the association between a history of parental alcohol use and binge drinking, and parental use and possible dependence on alcohol, in a national sample of junior high and high school students in Mexico. Method. A descriptive correlational study was carried out based on a secondary analysis of the National Survey of Student Drug Use (Encuesta Nacional de Consumo de Drogas en Estudiantes, ENCODE), which questioned 114,364 respondents. The association was evaluated with an estimate of prevalence ratios (PR). Results. Students whose mothers or both parents used alcohol had a greater risk for binge drinking (PR [mother] = 2.12, p #abr# .001; PR [both parents] = 2.18, p #abr# .001) and possible alcohol dependence (PR [mother] = 5.43, p #abr# .001; PR [both parents] = 5.14, p #abr# .001). Those whose fathers alone used alcohol had a lower risk for binge drinking (PR = 1.35, p #abr# .001) and for possible dependence (PR = 1.83, p #abr# .001). Discussion and conclusion. This study shows differences in the effects of problematic alcohol use by parents: use by the mother or by both parents implies a greater risk of binge drinking and possible dependence for their children. This finding should be considered in the design of interventions to prevent binge drinking.

Mechanisms of parent-child transmission of tobacco and alcohol use with polygenic risk scores: Evidence for a genetic nurture effect

Parent-child similarity is a function of genetic and environmental transmission. In addition, genetic effects not transmitted to offspring may drive parental behavior, thereby affecting the rearing environment of the child. Measuring genetic proclivity directly, through polygenic risk scores (PRSs), provides a way to test for the effect of nontransmitted parental genotype, on offspring outcome, termed a genetic nurture effect-in other words, if and how parental genomes might affect their children through the environment. The current study used polygenic risk scores for smoking initiation, cigarettes per day, and drinks per week to predict substance use in a sample of 3,008 twins, assessed prospectively from age 17-29, and their parents, from the Minnesota Center for Twin and Family Research. Mixed-effects models were used to test for a genetic nurture effect whereby parental PRSs predict offspring tobacco and alcohol use after statistically adjusting for offspring's own PRS. Parental smoking initiation PRS predicted offspring cigarettes per day at age 24 (β = .103, 95% CI [.03, .17]) and alcohol use at age 17 (β = .091, 95% CI [.04, .14]) independent of shared genetics. There was also a suggestive independent association between the parent PRS and offspring smoking at age 17 (β = .096; 95% CI [.02, .17]). Mediation analyses provided some evidence for environmental effects of parental smoking, alcohol use, and family socioeconomic status. These findings, and more broadly the molecular genetic method used, have implications on the identification of environmental effects on developmental outcomes such as substance use. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Parental risk constellations and future alcohol use disorder (AUD) in offspring: A combined HUNT survey and health registries study

OBJECTIVE

We examined the risk of developing a future alcohol use disorder (AUD) among offspring of families with different constellations of parental risk factors.

METHOD

We analyzed a sample of 8,774 offspring (50.2% male) from 6,696 two-parent families who participated in the Nord-Trøndelag Health Study in Norway when offspring were 13-19 years old in 1995-1997 or 2006-2008. Based on population registry information and parental Nord-Trøndelag Health Study self-reports, families were classified via Latent Profile Analysis into fiver risk constellations reflecting parents' education, drinking quantities and frequencies, and mental health. Information about AUD-related diagnoses, treatments, and prescriptions for all offspring in the period between 2008 and 2016 was obtained from 3 national health registries and pooled to reflect any AUD. The likelihood of AUD in offspring was examined with a set of nested logistic regression models.

RESULTS

Registry records yielded 186 AUD cases (2.1%). Compared with the lowest-risk constellation, offspring from two constellations were more likely to present with AUD in unadjusted analyses. After adjusting for all covariates, including offspring's alcohol consumption and witnessing parental intoxication during adolescence, AUD risk remained elevated and statistically significant (adjusted odds ratio = 2.34, 95% confidence interval = 1.14, 4.85) for offspring from the constellation characterized by at least weekly binge drinking, low education, and poor mental health in both parents.

CONCLUSION

Weekly binge drinking by both parents was associated with future AUD risk among community offspring in Norway when clustered with additional parental risks such as poor mental health and low educational attainment. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Prevalence and Correlates of Alcohol Consumption among Hill-Tribe Adolescents below the Legal Drinking Age-A Community-based Cross-Sectional Study in Northern Thailand

Alcohol drinking has been prevalent among various hill tribes of northern Thailand due to their distinctively different lifestyles, traditions, cultures and beliefs than the general Thai population; the majority of these traditions involve annual rounds of customary rituals that make alcohol abundantly accessible to all age groups. To study the prevalence and predictors of alcohol use, a community-based analytical cross-sectional study was conducted between October 2017-September 2018 among 480 sampled adolescents aged 12 through 18 years drawn by stratified random sampling. A proprietary questionnaire developed by the researchers was used to collect the data which were analyzed using binary logistic regression. The prevalence of alcohol use in the previous 30 days was 46.7%. Drinking predictors were: having at least a drinking parent, drinking peers, ever been sent to buy alcohol, smoking, cordial relationship with peers, gambling, family violence experience, stress and leisure time company. Therefore, our results suggest that prevention interventions should be designed with a focus on discouraging parents from sending children to buy alcohol and drinking or smoking in their presence; to reduce both social and commercial access to alcohol, age limits should be imposed on alcohol intake at all ceremonious events, while strictly reinforcing the law that prohibits selling alcohol to minors.

Family structure and alcohol use disorder: a register-based cohort study among offspring with and without parental alcohol use disorder

AIMS

To assess whether parental alcohol use disorder (AUD) is associated with higher risks of living in a non-intact family and assess whether non-intact family structure is associated with higher risks of AUD in the offspring.

DESIGN

Prospective cohort study.

SETTING

Danish nation-wide registries.

PARTICIPANTS

A total of 9948 parental AUD offspring and 98 136 reference offspring from the Danish population.

MEASUREMENTS

Family structure assessed at birth and at each birthday until age 15 as intact or non-intact (with mother only, father only or neither parent); years lived in an intact family defined as total number of years lived with both parents from birth until the 15th birthday; AUD defined as registration in medical, treatment and cause of death registries. Data were analyzed by Cox regression.

FINDINGS

At birth, 30.9% [95% confidence interval (CI) = 29.1-32.6] of parental AUD offspring and 10.7% (95% CI = 10.3-11.0) of reference offspring lived in a non-intact family. At age 15, the numbers were 84.6% (95% CI = 83.9-85.3) and 38.4% (95% CI = 38.1-38.7). Parental AUD was associated with a higher risk of offspring AUD [hazard ratio (HR) = 1.88, 95% CI = 1.74-2.02]. Offspring were at lower risk of AUD if they lived 15 years in an intact family compared with offspring who never lived in an intact family (HR = 0.67, 95% CI = 0.52-0.87 for those with parental AUD, and HR = 0.53, 95% CI = 0.48-0.59 for those whose parents did not have AUD). Findings were inconclusive as to whether or not an association was present between family structure and AUD among offspring with parental AUD and reference offspring.

CONCLUSIONS

The prevalence of non-intact family structure appears to be higher in offspring of parents with alcohol use disorder (AUD) than among offspring from the general population. Parental AUD appears to be associated with increased risk of offspring AUD, and non-intact family structure appears to be associated with increased risk of offspring AUD regardless of parental AUD.

Alexithymia, Impulsivity, and Reward Sensitivity in Young Adult University Student Children of Alcoholics

BACKGROUND AND OBJECTIVES

Personality traits previously known as risk factors for alcohol use disorder (AUD) were assessed in 29 young adult children of alcoholics (COAs) and 68 young adult children of nonalcoholics (non-COAs). Male and female university students (M_age = 22.11 years) completed questions pertaining to demographics and alcohol use, and the Children of Alcoholics Screening Test; Toronto Alexithymia Scale; Barratt Impulsiveness Scale; Sensitivity to Punishment and Sensitivity to Reward Questionnaire; and Depression Anxiety Stress Scales.

RESULTS

Results indicated that personality traits of alexithymia, reward sensitivity, and impulsivity, as well as negative moods, were significantly elevated in COAs compared to non-COAs, independent of current alcohol consumption and drinking history.

CONCLUSIONS

Findings are consistent with familial transmission of AUD-associated personality traits in COAs, presumably via influences of genetics and/or familial environment.

Influence of parental alcoholism on suicidal and personality-psychological characteristics of offspring

This article is a review of literature data, devoted to the influence of alcohol dependence of parents on the suicidal and personality-psychological characteristics of their offspring. Despite a decline of the incidence of alcohol dependence in the population, in Russia about 15-50% of families can say that they have encountered the problem of an alcoholized parent. Adult children of alcoholics (ACAs) are a fairly extensive, highly autoaggressive stratum of society. This group of people is the most dangerous in terms of the frequency of development in them of various kinds of addictions, as well as the likelihood of committing a suicidal attempt. The purpose of this review was to present modern ideas about the suicidality of adult children of alcoholics, their socio-cultural characteristics, personality and psychological characteristics; to demonstrate the degree of influence of addictive parental figures on the antivitality of offspring and its formation. The analysis of English and Russian literature is carried out. We have convincingly demonstrated that the ACAs represents a group with an elevated, relative to normative population, autoaggressiveness, inclination to parasuicidal patterns, with difficulties in building relationships with the society and finding a place in it. Conclusions were made about the inadequacy of the studies conducted, the lack of accurate data on the transgenerational mechanisms of autoaggressive transmission to offspring, the factors influencing the heterogeneity of the ACAs a population-species group, the need to take into account the gender of both parents and the ACAs themselves.

Examining interactions between genetic risk for alcohol problems, peer deviance, and interpersonal traumatic events on trajectories of alcohol use disorder symptoms among African American college students

Numerous studies have demonstrated that genetic and environmental factors interact to influence alcohol problems. Yet prior research has primarily focused on samples of European descent and little is known about gene–environment interactions in relation to alcohol problems in non-European populations. In this study, we examined whether and how genetic risk for alcohol problems and peer deviance and interpersonal traumatic events independently and interactively influence trajectories of alcohol use disorder symptoms in a sample of African American students across the college years (N = 1,119; Mage= 18.44 years). Data were drawn from the Spit for Science study where participants completed multiple online surveys throughout college and provided a saliva sample for genotyping. Multilevel growth curve analyses indicated that alcohol dependence genome-wide polygenic risk scores did not predict trajectory of alcohol use disorder symptoms, while family history of alcohol problems was associated with alcohol use disorder symptoms at the start of college but not with the rate of change in symptoms over time. Peer deviance and interpersonal traumatic events were associated with more alcohol use disorder symptoms across college years. Neither alcohol dependence genome-wide polygenic risk scores nor family history of alcohol problems moderated the effects of these environmental risk factors on alcohol use disorder symptoms. Our findings indicated that peer deviance and experience of interpersonal traumatic events are salient risk factors that elevate risk for alcohol problems among African American college students. Family history of alcohol problems could be a useful indicator of genetic risk for alcohol problems. Gene identification efforts with much larger samples of African descent are needed to better characterize genetic risk for alcohol use disorders, in order to better understand gene–environment interaction processes in this understudied population.

Revisiting the Children-of-Twins Design: Improving Existing Models for the Exploration of Intergenerational Associations

Datasets comprising twins and their children can be a useful tool for understanding the nature of intergenerational associations between parent and offspring phenotypes. In the present article we explore structural equation models previously used to analyse Children-of-Twins data, highlighting some limitations and considerations. We then present new variants of these models, showing that extending the models to include multiple offspring per parent addresses several of the limitations discussed. Accompanying the updated models, we provide power calculations and demonstrate with application to simulated data. We then apply to intergenerational analyses of height and weight, using a sub-study of the Norwegian Mother and Child Cohort (MoBa); the Intergenerational Transmission of Risk (IToR) project, wherein all kinships in the MoBa data have been identified (a children-of-twins-and-siblings study). Finally, we consider how to interpret the findings of these models and discuss future directions.

Perceived parental alcohol problems and drinking patterns in youth: A cross-sectional study of 69,030 secondary education students in Denmark

The aim of the study was to examine whether young people with parental alcohol problems have different drinking patterns than those without parental alcohol problems. Further, we examined whether the association between parental alcohol problems and young people's drinking patterns differed depending on the gender of the child and the parent, and whether more severe parental alcohol problems and cohabitation with the parent with alcohol problems was associated with earlier and heavier drinking patterns. Data came from the Danish National Youth Study 2014, a web-based national survey. 75,025 high school and vocational school students (15-25years) participated. Drinking patterns were investigated by the following outcomes: non-drinking, weekly alcohol consumption, frequent binge drinking, and early intoxication debut age. The main predictor variables were perceived parental alcohol problems, gender of the parent with alcohol problems, cohabitation with a parent with alcohol problems and severity of the parents' alcohol problems. Young people with parental alcohol problems had a higher weekly alcohol consumption (boys: 15.2 vs. 13.9 drinks per week; girls: 11.6 vs. 10.2 drinks per week), higher odds of early intoxication debut age (boys: OR=1.68 [95% CI 1.50-1.89]; girls: OR 1.95 [95% CI 1.79-2.14]), and more frequent binge drinking (boys, OR=1.16 [95% CI 1.04-1.29]; girls, OR=1.21 [95% CI 1.11-1.32]) compared to young people without parental alcohol problems. In conclusion, this study shows that young people with perceived parental alcohol problems have an earlier intoxication debut age, binge drink more frequently, and drink larger quantities per week than young people without perceived parental alcohol problems.

Prenatal Alcohol Exposure in Rodents As a Promising Model for the Study of ADHD Molecular Basis

A physiological parallelism, or even a causal effect relationship, can be deducted from the analysis of the main characteristics of the “Alcohol Related Neurodevelopmental Disorders” (ARND), derived from prenatal alcohol exposure (PAE), and the behavioral performance in the Attention-deficit/hyperactivity disorder (ADHD). These two clinically distinct disease entities, exhibits many common features. They affect neurological shared pathways, and also related neurotransmitter systems. We briefly review here these parallelisms, with their common and uncommon characteristics, and with an emphasis in the subjacent molecular mechanisms of the behavioral manifestations, that lead us to propose that PAE in rats can be considered as a suitable model for the study of ADHD.

A realist review of family-based interventions for children of substance abusing parents

BACKGROUND

Millions of children across North America and Europe live in families with alcohol or drug abusing parents. These children are at risk for a number of negative social, emotional and developmental outcomes, including an increased likelihood of developing a substance use disorder later in life. Family-based intervention programs for children with substance abusing parents can yield positive outcomes. This study is a realist review of evaluations of family-based interventions aimed at improving psychosocial outcomes for children of substance abusing parents (COSAPs). The primary objectives were to uncover patterns of contextual factors and mechanisms that generate program outcomes, and advance program theory in this field.

METHODS

Realist review methodology was chosen as the most appropriate method of systematic review because it is a theory-driven approach that seeks to explore mechanisms underlying program effectiveness (or lack thereof). A systematic and comprehensive search of academic and grey literature uncovered 32 documents spanning 7 different intervention programs. Data was extracted from the included documents using abstraction templates designed to code for contexts, mechanisms and outcomes of each program. Two candidate program theories of family addiction were used to guide data analysis: the family disease model and the family prevention model. Data analysis was undertaken by a research team using an iterative process of comparison and checking with original documents to determine patterns within the data.

RESULTS

Programs originating in both the family disease model and the family prevention model were uncovered, along with hybrid programs that successfully included components from each candidate program theory. Four demi-regularities were found to account for the effectiveness of programs included in this review: (1) opportunities for positive parent-child interactions, (2) supportive peer-to-peer relationships, (3) the power of knowledge, and (4) engaging hard to reach families using strategies that are responsive to socio-economic needs and matching services to client lived experience.

CONCLUSIONS

This review yielded new findings that had not otherwise been explored in COSAP program research and are discussed in order to help expand program theory. Implications for practice and evaluation are further discussed.

The interactive effect of paternal problem drinking and maternal problem drinking on adolescent internalizing problems

INTRODUCTION

This study examined the effects of both paternal problem drinking and maternal problem drinking on adolescent internalizing problems (depression and anxiety symptomatology).

METHODS

Surveys were administered to 566 10th and 11th grade students from the Mid-Atlantic region of the U.S. in the spring of 2007 and again in the spring of 2008.

RESULTS

Although significant main effects were not observed, significant interactions were found between paternal problem drinking and maternal problem drinking for internalizing problems, especially for boys. In general, these interactions indicated that when paternal problem drinking was high, depression symptomatology and anxiety symptomatology were lower if maternal problem drinking was low.

CONCLUSIONS

Findings from this study highlight the need to consider both paternal and maternal problem drinking when examining the effects that parental problem drinking may have on adolescent adjustment.

Integrating Social-Contextual and Intrapersonal Mechanisms of "Maturing Out": Joint Influences of Familial-Role Transitions and Personality Maturation on Problem-Drinking Reductions

BACKGROUND

"Maturing out" of problem drinking is associated with both role transitions (e.g., getting married) and personality development. However, little is known concerning how these 2 mechanisms jointly influence problem-drinking desistance. This study investigated whether salutary effects of role transitions and personality occur at different points in young-adult development and whether they mediate one another's effects.

METHODS

Participants were initially recruited as first-year undergraduates, with family history of alcoholism overrepresented by design (N = 489). Using 4 waves of data at roughly ages 21, 25, 29, and 34, cross-lagged panel models estimated prospective relations among familial-role transitions (marriage or parenthood), personality (disinhibition, conscientiousness, and neuroticism), and problem drinking.

RESULTS

Mixed support was found for the prediction of roles being more strongly associated with earlier maturing out of problem drinking and personality being more strongly associated with later maturing out. Regarding mediation, no evidence was found for the expectation that role effects would be mediated by personality. However, results did support mediation of personality effects by role transitions. Specifically, lower disinhibition and higher conscientiousness in emerging adulthood predicted role adoption, which, in turn, predicted later problem-drinking reductions. Family history of alcoholism also distally influenced these mediation processes.

CONCLUSIONS

The differential timing of role and personality effects is consistent with the notion of decreasing contextual influences and increasing intrapersonal influences across development. In light of role incompatibility theory, results suggest that, over the course of development, the association of familial roles with problem drinking may increasingly reflect problem-drinking effects on role entry (i.e., role selection) and decreasingly reflect role entry effects on problem drinking (i.e., role socialization). As emerging-adult disinhibition and conscientiousness were associated with an apparent developmental cascade of both direct and indirect effects, findings highlight their potential importance as etiologic mechanisms and intervention targets.

Predicting an Alcohol Use Disorder in Urban American Indian Youth

This study examines predictors of alcohol use disorders (AUDs) among an urban American Indian cohort who were followed from approximately age 11 to age 20. Approximately 27% of the sample had a lifetime diagnosis of alcohol abuse or dependence. The results indicated that externalizing, but not internalizing, behaviors, family conflict, and school liking served as significant predictors of an AUD. Neither having an alcoholic mother nor an alcoholic father was found to be significantly predictive of an alcohol use disorder at ages 19-20. Finally, early alcohol initiation is a substantial predictor of an AUD and acts as a partial mediator.

Parental separation and early substance involvement: results from children of alcoholic and cannabis dependent twins

BACKGROUND

Risks associated with parental separation have received limited attention in research on children of parents with substance use disorders. We examined early substance involvement as a function of parental separation during childhood and parental alcohol and cannabis dependence.

METHOD

Data were drawn from 1318 adolescent offspring of monozygotic (MZ) or dizygotic (DZ) Australian twin parents. Cox proportional hazards regression analyses were conducted predicting age at first use of alcohol, first alcohol intoxication, first use and first regular use of cigarettes, and first use of cannabis, from parental separation and both parent and cotwin substance dependence. Parent and cotwin alcohol and cannabis dependence were initially modeled separately, with post hoc tests for equality of effects.

RESULTS

With few exceptions, risks associated with parental alcohol versus cannabis dependence could be equated, with results largely suggestive of genetic transmission of risk from parental substance (alcohol or cannabis) dependence broadly defined. Controlling for parental substance dependence, parental separation was a strong predictor for all substance use variables, especially through age 13.

CONCLUSION

Together, findings underscore the importance of parental separation as a risk-factor for early substance involvement over and above both genetic and environmental influences specific to parental alcohol and cannabis dependence.

Accounting for the physical and mental health benefits of entry into marriage: a genetically informed study of selection and causation

Married adults show better psychological adjustment and physical health than their separated/divorced or never-married counterparts. However, this apparent "marriage benefit" may be due to social selection, social causation, or both processes. Genetically informed research designs offer critical advantages for helping to disentangle selection from causation by controlling for measured and unmeasured genetic and shared environmental selection. Using young-adult twin and sibling pairs from the National Longitudinal Study of Adolescent Health (Harris, 2009), we conducted genetically informed analyses of the association between entry into marriage, cohabitation, or singlehood and multiple indices of psychological and physical health. The relation between physical health and marriage was completely explained by nonrandom selection. For internalizing behaviors, selection did not fully explain the benefits of marriage or cohabitation relative to being single, whereas for externalizing symptoms, marriage predicted benefits over cohabitation. The genetically informed approach provides perhaps the strongest nonexperimental evidence that these observed effects are causal.

Investigating the influence of prenatal androgen exposure and sibling effects on alcohol use and alcohol use disorder in females from opposite-sex twin pairs

BACKGROUND

There are robust sex differences for alcohol phenotypes, with men reporting more drinking and alcohol use disorder (AUD) symptoms than women. However, the sources of these effects are not completely understood. Sex hormones, a substantial biological sex difference, exert neurobehavioral influences and are candidates for influencing sex differences in alcohol phenotypes. This study investigated the effects of prenatal androgens based on the hypothesis of prenatal hormone transfer, which posits that hormones from one twin influence the development of a cotwin.

METHODS

This study compared female twins from opposite-sex (OSF) and same-sex (SSF) pairs to investigate associations between prenatal androgens and alcohol phenotypes. Additional analyses distinguished prenatal and postnatal effects by comparing OSFs and SSFs with a close-in-age older (CAO) brother.

RESULTS

OSFs endorsed more lifetime AUD symptoms than SSFs (d = 0.14). Females with a CAO brother reported greater intoxication frequency (d = 0.35), hangover frequency (d = 0.24), typical drinking quantity (d = 0.33), and max drinks (i.e., the most drinks ever consumed in a 24-hour period; d = 0.29). Controlling for postnatal effects, OSFs still endorsed more lifetime AUD symptoms than SSFs with a CAO brother (d = 0.16).

CONCLUSIONS

Prenatal exposure to a male cotwin was associated with increases in AUD symptoms, above the effect of postnatal exposure to a male sibling. Prenatal exposure to a male cotwin was not associated with increases in other alcohol-related phenotypes, but postnatal exposure to older male siblings produced medium effect sizes for indicators of alcohol consumption. Sex differences in AUDs, but not alcohol use, may be partially due to the neurodevelopmental effects of prenatal androgens. However, sibling effects may be larger than any effect of prenatal androgen exposure.

Current parental depression and offspring perceived self-competence: a quasi-experimental examination

A genetically-informed, quasi-experimental design was used to examine the genetic and environmental processes underlying associations between current parental depressive symptoms and offspring perceived self-competence. Participants, drawn from a population-based Swedish sample, were 852 twin pairs and their male (52 %) and female offspring aged 15.7 ± 2.4 years. Parental depressive symptoms were measured using the Center for Epidemiological Studies Depression scale. Offspring perceived self-competence was measured using a modified Harter Perceived Competence Scale. Cousin comparisons and Children of Twins designs suggested that associations between maternal depressive symptoms and offspring perceived self-competence were due to shared genetic/environmental liability. The mechanism responsible for father-offspring associations, however, was independent of genetic factors and of extended family environmental factors, supporting a causal inference. Thus, mothers and fathers may impact offspring perceived self-competence via different mechanisms and unmeasured genetic and environmental selection factors must be considered when studying the intergenerational transmission of cognitive vulnerabilities for depression.

Unraveling the effect of genes and environment in the transmission of parental antisocial behavior to children's conduct disturbance, depression and hyperactivity

BACKGROUND

  A critical issue in devising effective interventions for the treatment of children's behavioral and emotional problems identifying genuine family environmental factors that place children at risk. In most twin and family studies, environmental factors are confounded with both direct genetic risk from parents and the indirect effect of genes influencing parents' ability to provide an optimal rearing environment. The present study was undertaken to determine whether parental psychopathology, specifically parental antisocial behavior (ASP), is a genuine environmental risk factor for juvenile conduct disturbance, depression and hyperactivity, or whether the association between parental ASP and children's behavioral and emotional problems can be explained as a secondary consequence of the intergenerational transmission of genetic factors.

METHODS

  An extended children of twins design comprised of data collected on 2,674 adult female and male twins, their spouses, and 2,454 of their children was used to test whether genetic and/or family environmental factors best accounted for the association between parental antisocial behavior and children's behavioral problems. An age-matched sample of 2,826 juvenile twin pairs from the Virginia Twin Study of Adolescent Behavioral Development was also included to examine developmental differences in gene expression by partitioning child-specific transmissible effects from those effects that persist into adulthood. The fit of alternative models was evaluated using the statistical program Mx.

RESULTS

  We found distinct patterns of transmission between parental antisocial behavior and juvenile conduct, depression and hyperactivity. Genetic and family environmental factors accounted for the resemblance between parents' ASP and children's conduct disturbance. Family environmental factors alone explained the association between child depression and parental ASP, and the impact of parental ASP on hyperactivity was entirely genetic.

CONCLUSIONS

  These findings underscore differences in the contribution of genetic and environmental factors on the patterns of association between parental antisocial behavior and juvenile psychopathology, having important clinical implications for the prevention and amelioration of child behavioral and emotional problems.

A quasi-experimental analysis of the influence of neighborhood disadvantage on child and adolescent conduct problems

A quasi-experimental comparison of cousins differentially exposed to levels of neighborhood disadvantage (ND) was used with extensive measured covariates to test the hypothesis that neighborhood risk has independent effects on youth conduct problems (CPs). Multilevel analyses were based on mother-rated ND and both mother-reported CPs across 4-13 years (n = 7,077) and youth-reported CPs across 10-13 years (n = 4,524) from the Children of the National Longitudinal Survey of Youth. ND was robustly related to CPs reported by both informants when controlling for both measured risk factors that are correlated with ND and unmeasured confounds. These findings are consistent with the hypothesis that ND has influence on conduct problems.

Parental depression and offspring psychopathology: a children of twins study

BACKGROUND

Associations between parental depression and offspring affective and disruptive disorders are well documented. Few genetically informed studies have explored the processes underlying intergenerational associations.

METHOD

A semi-structured interview assessing DSM-III-R psychiatric disorders was administered to twins (n=1296) from the Australian Twin Register (ATR), their spouses (n=1046) and offspring (n=2555). We used the Children of Twins (CoT) design to delineate the extent to which intergenerational associations were consistent with a causal influence or due to genetic confounds.

RESULTS

In between-family analyses, parental depression was associated significantly with offspring depression [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.20-1.93] and conduct disorder (CD; HR 2.27, CI 1.31-3.93). Survival analysis indicated that the intergenerational transmission of depression is consistent with a causal (environmental) inference, with a significant intergenerational association in offspring of discordant monozygotic (MZ) twin pairs (HR 1.39, CI 1.00-1.94). Logistic regression analysis suggested that the parental depression-offspring CD association was due to shared genetic liability in the parents and offspring. No intergenerational association was found when comparing the offspring of discordant MZ twins [odds ratio (OR) 1.41, CI 0.63-3.14], but offspring of discordant dizygotic (DZ) twins differed in their rates of CD (OR 2.53, CI 0.95-6.76). All findings remained after controlling for several measured covariates, including history of depression and CD in the twins' spouses.

CONCLUSIONS

The mechanisms underlying associations between parental depression and offspring psychopathology seem to differ depending on the outcome. The results are consistent with a causal environmental role of parental depression in offspring depression whereas common genetic factors account for the association of parental depression and offspring CD.

The contribution of parental alcohol use disorders and other psychiatric illness to the risk of alcohol use disorders in the offspring

BACKGROUND

Few population-based studies have investigated associations between parental history of alcoholism and the risk of alcoholism in offspring. The aim was to investigate in a large cohort the risk of alcohol use disorders (AUD) in the offspring of parents with or without AUD and with or without hospitalization for other psychiatric disorder (OPD).

METHODS

Longitudinal birth cohort study included 7,177 men and women born in Copenhagen between October 1959 and December 1961. Cases of AUD were identified in 3 Danish health registers and cases of OPD in the Danish Psychiatric Central Register. Offspring registration with AUD was analyzed in relation to parental registration with AUD and OPD. Covariates were offspring gender and parental social status.

RESULTS

Both maternal and paternal registration with AUD significantly predicted offspring risk of AUD (odds ratios 1.96; 95% CI 1.42 to 2.71 and 1.99; 95% CI 1.54 to 2.68, respectively). The association between maternal, but not paternal, OPD and offspring AUD was also significant (odds ratios 1.46; 95% CI 1.15 to 1.86 and 1.26; 95% CI 0.95 to 1.66, respectively). Other predictors were male gender and parental social status. A significant interaction was observed between paternal AUD and offspring gender on offspring AUD, and stratified analyses showed particularly strong associations of both paternal and maternal AUD with offspring AUD in female cohort members.

CONCLUSIONS

Parental AUD was associated with an increased risk of offspring AUD independent of other significant predictors, such as gender, parental social status, and parental psychiatric hospitalization with other diagnoses. Furthermore, this association appeared to be stronger among female than male offspring. The results suggest that inherited factors related to alcoholism are at least as important in determining the risk of alcoholism among daughters as among sons.

Psychopathology in offspring from families of alcohol dependent female probands: a prospective study

BACKGROUND

Despite the importance of understanding the long-term outcome for children of alcohol dependent (AD) women, the available literature is largely based on offspring of AD fathers and few have utilized prospective designs that include child, adolescent and young adult assessments. Multiplex AD families in which multiple cases of AD are present provide an ideal setting for understanding developmental variants of the adult phenotype.

METHOD

Offspring from multiplex AD families identified through the mother or control families were evaluated multiple times during childhood and followed to young adulthood. Familial risk status and the presence of specific child/adolescent disorders were used as predictors of substance use disorder outcome by young adulthood.

RESULTS

Offspring who were members of maternal multiplex families had elevated rates of child and young adulthood disorders. High risk offspring of alcohol dependent women were at increased risk for externalizing (Conduct Disorder and ADHD) and internalizing disorders (Major Depressive Disorder (MDD) and Anxiety Disorders). By young adulthood, offspring from these multiplex families had significantly greater odds of developing alcohol abuse or dependence (odds ratio [OR] = 3.63 [CI 1.36-9.64]) and drug abuse or dependence (OR = 4.23 [CI 1.73-10.32]). The prospective design of the study revealed that specific childhood disorders (Conduct Disorder, ADHD, MDD) increased the odds of subsequent development of substance use disorder (SUD).

CONCLUSIONS

Multiplex familial risk for alcohol dependence is a significant predictor of substance use disorders by young adulthood. Familial risk and an earlier childhood disorder may set the stage for later development of SUD.

Does religious involvement protect against early drinking? A behavior genetic approach

BACKGROUND

Adolescent involvement in religious organizations has been hypothesized to protect against early age at first drink. However, the correlation between adolescent religiosity and later age at first drink may be confounded by environmental or genetic differences between families. This study tests whether, after controlling for shared environmental and genetic confounds using a behavior genetic design, the association between individual levels of religiosity and earlier age at first drink is still evident.

METHOD

Twin and sibling pairs were drawn from the National Longitudinal Study of Adolescent Health, a nationally-representative sample of US adolescents. Age at first drink was measured as how old adolescents were when they first had a drink of beer, wine, or liquor. Religiosity was measured using four items concerning frequency of religious activities and importance of religious beliefs. Using twins and siblings who were discordant for religiosity, analyses tested whether religious adolescents had a later age at first drink than their non-religious co-twins/co-siblings.

RESULTS

Religious adolescents did not differ from their non-religious siblings in their mean age at first drink. Results from survival models indicate that environmental differences between families completely account for the correlation between religiosity and later age at first drink.

CONCLUSIONS

Results suggest that individual religious involvement is a proxy variable for family or cultural environments that are salient for when adolescents initiate alcohol use. Future research is needed to identify specific protective environments in religious families. These results have implications for both public policy and etiological theory.

Consilient research approaches in studying gene x environment interactions in alcohol research

This review article discusses the importance of identifying gene-environment interactions for understanding the etiology and course of alcohol use disorders and related conditions. A number of critical challenges are discussed, including the fact that there is no organizing typology for classifying different types of environmental exposures, many key human environmental risk factors for alcohol dependence have no clear equivalents in other species, much of the genetic variance of alcohol dependence in human is not 'alcohol specific', and the potential range of gene-environment interactions that could be considered is so vast that maintaining statistical control of Type 1 errors is a daunting task. Despite these and other challenges, there appears to be a number of promising approaches that could be taken in order to achieve consilience and ecologically valid translation between human alcohol dependence and animal models. Foremost among these is to distinguish environmental exposures that are thought to have enduring effects on alcohol use motivation (and self-regulation) from situational environmental exposures that facilitate the expression of such motivations but do not, by themselves, have enduring effects. In order to enhance consilience, various domains of human approach motivation should be considered so that relevant environmental exposures can be sampled, as well as the appropriate species to study them in (i.e. where such motivations are ecologically relevant). Foremost among these are social environments, which are central to the initiation and escalation of human alcohol consumption. The value of twin studies, human laboratory studies and pharmacogenetic studies is also highlighted.

Testing the equal environments assumption in the Children of Twins design

In a Children of Twins (COT) design, the environmental and genetic risk of a child is, in part, dependent upon the status of the father and the father's cotwin. The logic of the COT method breaks down if the zygosity of the twin pair is confounded with the environment provided to the child (a version of the Equal Environment Assumption, EEA). If MZ twin fathers see each other more often than DZ twin fathers, and a child's uncle is the affected twin in discordant pairs, this could increase the environmental risk of children of MZ over that of DZ discordant twins. The current study was designed to test the EEA in the COT design, specifically in children of alcohol and drug dependent fathers. Results indicated that MZ twins did have more contact than DZ twins. Regression analyses were conducted to predict child externalizing symptom counts from father's zygosity group status, level of contact with father's cotwin, and their interaction. Results found no significant interaction between father's zygosity and the higher level of cotwin contact (seen in MZ twins) in predicting several measures of offspring externalizing risk. The results of this study suggested that the COT design does not confound zygosity with differences in environmental risk exposure, findings that support the validity of the EEA within this research context.

Parental alcoholism and offspring behavior problems: findings in Australian children of twins

We examine the impact of rearing by an alcoholic parent on risk for child behavior problems using data on 2492 offspring drawn from two ongoing studies of children of female and male same- and opposite-sex twin pairs. Results of regression models predicting child behavior problems from parent and co-twin lifetime history of alcohol use disorder (AUD) provide support for genetic but not environmental transmission of externalizing and a measure of total problem behaviors. Results for internalizing behavior were inconclusive with respect to transmission of risk.

Gender differences in factors influencing alcohol use and drinking progression among adolescents

While prevalence rates for alcohol use and related disorders differ widely between adult men and women, male and female adolescents do not exhibit the same disparity in alcohol consumption. Previous research and reviews do not address the emergence of differences in drinking patterns that occur during late adolescence. Therefore, a developmental perspective is presented for understanding how various risk and protective factors associated with problematic drinking affect diverging alcohol trajectories as youth move into young adulthood. This review examines factors associated with risk for developing an alcohol use disorder in adolescent girls and boys separately. Findings indicate that certain biological (i.e., genetic risk, neurological abnormalities associated with P300 amplitudes) and psychosocial (i.e., impact of positive drinking expectancies, personality characteristics, and deviance proneness) factors appear to impact boys and girls similarly. In contrast, physiological and social changes particular to adolescence appear to differentially affect boys and girls as they transition into adulthood. Specifically, boys begin to manifest a constellation of factors that place them at greater risk for disruptive drinking: low response to alcohol, later maturation in brain structures and executive function, greater estimates of perceived peer alcohol use, and socialization into traditional gender roles. On an individual level, interventions which challenge media-driven stereotypes of gender roles while simultaneously reinforcing personal values are suggested as a way to strengthen adolescent autonomy in terms of healthy drinking decisions. Moreover, parents and schools must improve consistency in rules and consequences regarding teen drinking across gender to avoid mixed messages about acceptable alcohol use for boys and girls.

Parental alcohol dependence and the transmission of adolescent behavioral disinhibition: a study of adoptive and non-adoptive families

AIM

To examine the genetic and environmental influences of parental alcoholism on offspring disinhibited behavior.

DESIGN

We compared the effect of parental alcoholism history on offspring in adoptive and non-adoptive families. In families with a history of parental alcohol dependence, we examined the effect of exposure to parental alcoholism symptoms during the life-time of the adolescent. Setting Assessments occurred at the University of Minnesota from 1998 to 2004.

PARTICIPANTS

Adolescents adopted in infancy were ascertained systematically from records of three private Minnesota adoption agencies; non-adopted adolescents were ascertained from Minnesota birth records. Adolescents and their rearing parents participated in in-person assessments.

MEASUREMENTS

For adolescents, measures included self- reports of delinquency, deviant peers, substance use, antisocial attitudes and personality. For parents, we conducted DSM-IV clinical assessments of alcohol abuse and dependence.

FINDINGS

A history of parental alcohol dependence was associated with higher levels of disinhibition only when adolescents were related biologically to their rearing parents. Within families with a history of parental alcoholism, exposure to parental alcohol misuse during the life-time of the adolescent was associated with increased odds of using alcohol in adopted adolescents only.

CONCLUSIONS

These findings suggest that the association between a history of parental alcohol dependence and adolescent offspring behavioral disinhibition is attributable largely to genetic rather than environmental transmission. We also obtained some evidence for parental alcohol misuse as a shared environmental risk factor in adoptive families.