Mapping Pathways by Which Genetic Risk Influences Adolescent Externalizing Behavior: The Interplay Between Externalizing Polygenic Risk Scores, Parental Knowledge, and Peer Substance Use

Limited psychological and social effects of lifetime cannabis use frequency: Evidence from a 30-year community study of 4,078 twins

BACKGROUND

Cannabis use is associated with outcomes like income, legal problems, and psychopathology. This finding rests largely on correlational research designs, which rely at best on statistical controls for confounding. Here, we control for unmeasured confounders using a longitudinal study of twins.

METHOD

In a sample of 4,078 American adult twins first assessed decades ago, we used cotwin control mixed effects models to evaluate the effect of lifetime average frequency of cannabis consumption measured on substance use, psychiatric, and psychosocial outcomes.

RESULTS

On average, participants had a lifetime cannabis frequency of about one to two times per month, across adolescence and adulthood. As expected, in individual-level analyses, cannabis use was significantly associated with almost all outcomes in the expected directions. However, when comparing each twin to their cotwin, which inherently controls for shared genes and environments, we observed within-pair differences consistent with possible causality in three of the 22 assessed outcomes: cannabis use disorder symptoms (βW-Pooled = .15, SE = .02, p = 1.7 × 10-22), frequency of tobacco use (βW-Pooled = .06, SE = .01, p = 1.2 × 10-5), and illicit drug involvement (βW-Pooled = .06, SE = .02, p = 1.2 × 10-4). Covariate specification curve analyses indicated that within-pair effects on tobacco and illicit drug use, but not cannabis use disorder, attenuated substantially when covarying for lifetime alcohol and tobacco use.

CONCLUSIONS

The cotwin control results suggest that more frequent cannabis use causes small increases in cannabis use disorder symptoms, approximately 1.3 symptoms when going from a once-a-year use to daily use. For other outcomes, our results are more consistent with familial confounding, at least in this community population of twins. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Examining associations between genetic and neural risk for externalizing behaviors in adolescence and early adulthood

BACKGROUND

Researchers have identified genetic and neural risk factors for externalizing behaviors. However, it has not yet been determined if genetic liability is conferred in part through associations with more proximal neurophysiological risk markers.

METHODS

Participants from the Collaborative Study on the Genetics of Alcoholism, a large, family-based study of alcohol use disorders were genotyped and polygenic scores for externalizing (EXT PGS) were calculated. Associations with target P3 amplitude from a visual oddball task (P3) and broad endorsement of externalizing behaviors (indexed via self-report of alcohol and cannabis use, and antisocial behavior) were assessed in participants of European (EA; N = 2851) and African ancestry (AA; N = 1402). Analyses were also stratified by age (adolescents, age 12-17 and young adults, age 18-32).

RESULTS

The EXT PGS was significantly associated with higher levels of externalizing behaviors among EA adolescents and young adults as well as AA young adults. P3 was inversely associated with externalizing behaviors among EA young adults. EXT PGS was not significantly associated with P3 amplitude and therefore, there was no evidence that P3 amplitude indirectly accounted for the association between EXT PGS and externalizing behaviors.

CONCLUSIONS

Both the EXT PGS and P3 amplitude were significantly associated with externalizing behaviors among EA young adults. However, these associations with externalizing behaviors appear to be independent of each other, suggesting that they may index different facets of externalizing.

The Collaborative Study on the Genetics of Alcoholism: Overview

Alcohol use disorders (AUD) are commonly occurring, heritable and polygenic disorders with etiological origins in the brain and the environment. To outline the causes and consequences of alcohol-related milestones, including AUD, and their related psychiatric comorbidities, the Collaborative Study on the Genetics of Alcoholism (COGA) was launched in 1989 with a gene-brain-behavior framework. COGA is a family based, diverse (~25% self-identified African American, ~52% female) sample, including data on 17,878 individuals, ages 7-97 years, in 2246 families of which a proportion are densely affected for AUD. All participants responded to questionnaires (e.g., personality) and the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) which gathers information on psychiatric diagnoses, conditions and related behaviors (e.g., parental monitoring). In addition, 9871 individuals have brain function data from electroencephalogram (EEG) recordings while 12,009 individuals have been genotyped on genome-wide association study (GWAS) arrays. A series of functional genomics studies examine the specific cellular and molecular mechanisms underlying AUD. This overview provides the framework for the development of COGA as a scientific resource in the past three decades, with individual reviews providing in-depth descriptions of data on and discoveries from behavioral and clinical, brain function, genetic and functional genomics data. The value of COGA also resides in its data sharing policies, its efforts to communicate scientific findings to the broader community via a project website and its potential to nurture early career investigators and to generate independent research that has broadened the impact of gene-brain-behavior research into AUD.

Polygenic Effects on Individual Rule Breaking, Peer Rule Breaking, and Alcohol Sips Across Early Adolescence in the ABCD Study

Alcohol use emerges during early adolescence and is strongly associated with individual and peer risky, delinquent, and rule breaking behaviors. Genetic predisposition for risky behavior contributes to individual rule breaking in adolescence and can also evoke peer rule breaking or lead youth to select into delinquent peer groups via gene-environment correlations (rGE), collectively increasing risk for alcohol use. Little research has examined whether genetic predisposition for risky behavior contributes to individual and peer rule breaking behavior in developmental pathways to alcohol use in early adolescence or in large diverse racial/ethnic populations. To address this, polygenic scores for risky behavior were considered predictors of individual rule breaking, peer rule breaking, and alcohol sips using data from the Adolescent Brain Cognitive Development (ABCD) study at age 11-12 and 12-13 in a cross-time cross-lagged model. This was examined separately in European American (EA; n = 5113; 47% female), African American (AA; n = 1159; 50% female), and Hispanic/Latinx (Latinx; n = 1624; 48% female) subgroups accounting for sociodemographic covariates and genetic ancestry principal components. Polygenic scores were positively associated with all constructs in EAs, with individual rule breaking at age 11-12 in AAs and Latinx, and with alcohol sips at age 11-12 in Latinx. Individual and peer rule breaking were associated with one another across time only in the EA subgroup. In all subgroups, peer rule breaking at 12-13 was associated with alcohol sips at 12-13. Results indicate that alcohol sips in early adolescence are associated with individual and peer rule breaking with rGE implicated in EAs.

A person-centered data analytic approach to dopaminergic polygenic moderation of child maltreatment exposure

The present study illustrates the utility of latent class analysis, a person-centered data analytic approach, as an innovative method for identifying naturally occurring patterns of polygenic risk, specifically within the dopaminergic system. Moreover, this study tests whether latent classes of polygenic variation moderate the effect of child maltreatment exposure on internalizing symptoms among African ancestry youth. African ancestry youth were selected for this study because youth of color are overrepresented in the child welfare system and because African ancestry individuals are significantly underrepresented in genomics research. Results identified three latent classes of dopaminergic gene variation. Class 1 was marked predominately by homozygous minor alleles, Class 2 was characterized by homozygous major and heterozygous presentations, and Class 3 was marked by heterozygous alleles on the DAT-1 single-nucleotide polymorphisms (SNPs) and a combination of homozygous major and minor alleles on the other SNPs. Results indicated that a greater number of maltreatment subtypes experienced were associated with higher internalizing symptoms only for children with the latent polygenic Class 2 pattern. This latent class was distinctly characterized by more homozygous major or heterozygous allelic presentations along all three DAT-1 SNPs. This significant latent polygenic class by environment interaction was replicated in an independent replication sample. Together, findings suggest that African ancestry children with a pattern of dopaminergic variation characterized by this specific combination of polygenic variation are more vulnerable to developing internalizing symptoms following maltreatment exposure, relative to their peers with other dopamine-related polygenic patterns.

Do polygenic indices capture "direct" effects on child externalizing behavior? Within-family analyses in two longitudinal birth cohorts

Behaviors and disorders characterized by difficulties with self-regulation, such as problematic substance use, antisocial behavior, and symptoms of attention-deficit/hyperactivity disorder (ADHD), incur high costs for individuals, families, and communities. These externalizing behaviors often appear early in the life course and can have far-reaching consequences. Researchers have long been interested in direct measurements of genetic risk for externalizing behaviors, which can be incorporated alongside other known risk factors to improve efforts at early identification and intervention. In a preregistered analysis drawing on data from the Environmental Risk (E-Risk) Longitudinal Twin Study (N = 862 twins) and the Millennium Cohort Study (MCS; N = 2,824 parent-child trios), two longitudinal cohorts from the UK, we leveraged molecular genetic data and within-family designs to test for genetic effects on externalizing behavior that are unbiased by the common sources of environmental confounding. Results are consistent with the conclusion that an externalizing polygenic index (PGI) captures causal effects of genetic variants on externalizing problems in children and adolescents, with an effect size that is comparable to those observed for other established risk factors in the research literature on externalizing behavior. Additionally, we find that polygenic associations vary across development (peaking from age 5-10 years), that parental genetics (assortment and parent-specific effects) and family-level covariates affect prediction little, and that sex differences in polygenic prediction are present but only detectable using within-family comparisons. Based on these findings, we believe that the PGI for externalizing behavior is a promising means for studying the development of disruptive behaviors across child development.

Unraveling the Bidirectional Associations between Parental Knowledge and Children's Externalizing Behavior

Although within- and between-family bidirectional associations between parental knowledge and children's externalizing behavior have been theoretically proposed, studies that unravel these associations simultaneously remain scarce. This study examined these bidirectional associations within and between German families. 3611 families participated across one-year intervals between children ages 8 to 15 (50.6% boys, 34.5% fathers, 89.0% German-born, M_waves = 3.63, SD_waves = 2.00). Random intercept cross-lagged panel models (RI-CLPM) with linear slopes revealed negative between-family associations between parental knowledge and children's externalizing behavior, and a negative association between the random linear slopes. Generally, no within-family cross-lagged effects were found, but there were some correlated slopes across families. When teasing apart paternal and maternal knowledge, father-driven but not mother-driven lagged effects of increased knowledge predicting decreased externalizing behavior were found. The findings illustrate the importance of fathers' knowledge and new directions for within-family studies of parent-child interactions.

Hazardous drinking and alcohol use disorders

Alcohol is one of the most widely consumed psychoactive drugs globally. Hazardous drinking, defined by quantity and frequency of consumption, is associated with acute and chronic morbidity. Alcohol use disorders (AUDs) are psychiatric syndromes characterized by impaired control over drinking and other symptoms. Contemporary aetiological perspectives on AUDs apply a biopsychosocial framework that emphasizes the interplay of genetics, neurobiology, psychology, and an individual's social and societal context. There is strong evidence that AUDs are genetically influenced, but with a complex polygenic architecture. Likewise, there is robust evidence for environmental influences, such as adverse childhood exposures and maladaptive developmental trajectories. Well-established biological and psychological determinants of AUDs include neuroadaptive changes following persistent use, differences in brain structure and function, and motivational determinants including overvaluation of alcohol reinforcement, acute effects of environmental triggers and stress, elevations in multiple facets of impulsivity, and lack of alternative reinforcers. Social factors include bidirectional roles of social networks and sociocultural influences, such as public health control strategies and social determinants of health. An array of evidence-based approaches for reducing alcohol harms are available, including screening, pharmacotherapies, psychological interventions and policy strategies, but are substantially underused. Priorities for the field include translating advances in basic biobehavioural research into novel clinical applications and, in turn, promoting widespread implementation of evidence-based clinical approaches in practice and health-care systems.

A broad internalizing dimension accounts for the genetic associations between personality and individual internalizing disorders

Much research has demonstrated that psychopathology can be described in terms of broad dimensions, representing liability for multiple psychiatric disorders. Broad spectra of psychopathology (e.g., internalizing and externalizing) are increasingly used as targets for research investigating the development, etiology, and course of psychopathology because they account for patterns of relatedness among disorders that were once presumed distinct. Thus, these spectra represent alluring targets due to their comprehensive and parsimonious nature. Nevertheless, little research has established the role of individual disorders over and above broad dimensions in the study of psychopathology. In the current study, we investigate whether there are unique etiological associations between individual internalizing disorders and personality traits after accounting for their etiological associations with a broad internalizing dimension. We used a community sample of twins (Npairs = 448) ages 4 to 19 to examine the etiological associations between internalizing psychopathology and Big Five personality dimensions. In terms of genetic covariation, a broad internalizing dimension was positively associated with neuroticism and negatively associated with extraversion, agreeableness, and conscientiousness. Moreover, internalizing accounted for most of the genetic variance shared between individual internalizing disorders and personality traits. Nevertheless, there were unique genetic associations between the following pairs of personality traits and disorders: neuroticism and social anxiety, extraversion and social anxiety, agreeableness and depression, and conscientiousness and compulsions. There was little evidence of environmental influences shared between internalizing and personality. In sum, a broad internalizing dimension adequately accounted for almost all of the etiologic covariation between internalizing disorders and personality, with several interesting exceptions. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Associations between parenting characteristics and adolescent substance use: A genetically informed, longitudinal adoption study

The present study examined putative environmental predictors of adolescent substance use, using a prospective adoption design to distinguish between environmental mediation (i.e., parenting influencing adolescent substance use), passive gene-environment correlation (i.e., parental genetic predisposition influencing the association between parenting characteristics and adolescent substance use), and evocative gene-environment correlation (i.e., children's genetic predisposition influencing parenting). Longitudinal data from the Colorado Adoption Project (395 adoptees, 491 nonadoptees, 485 adoptive parents, and 490 biological parents) were examined. Children (48% girls) were assessed at ages 1 to 17 years. Over 90% of the sample were non-Hispanic White. Associations between parenting and adolescent substance use were compared between adoptive and nonadoptive families. Positive, negative, and inconsistent parenting measures in early childhood through adolescence were not consistently associated with adolescent substance use, with only 6% of correlations being statistically significant (r = -0.152 to .207). However, parent-child relationship quality assessed from childhood to adolescence and orientation to parents assessed during adolescence were significantly, negatively associated with adolescent substance use, with 71% of correlations being statistically significant (r = -0.88 to -0.11). There was little evidence of sex differences in the associations. Environmental mediation, rather than passive or evocative gene-environment correlation, explained most associations.

Alcohol Misuse among English Youth, Are Harms Attributable to Alcohol or to Underlying Disinhibitory Characteristics?

INTRODUCTION

Alcohol use by young people is associated with a range of psychological and physical harms. However, similar harms are also reported with disinhibitory conditions such as conduct problems that are said to precede and predispose to alcohol misuse. We explored whether alcohol use or indicators of underlying disinhibition predict psychological and physical harms in a cohort of young people.

METHODS

We used data from a randomised controlled intervention trial that identified young people who consumed alcohol (n = 756), mean age = 15.6 years, attending emergency departments (EDs) in England. Disinhibition was measured by the self-report Strengths and Difficulties Questionnaire hyperactivity and conduct problem items, and alcohol-related harms by questions from the ESPAD, a major European school survey. We conducted a mediation analysis with a primary outcome of frequency of engaging in alcohol-related harms 12 months after screening in ED, exploring for the mediating influence of alcohol consumed at six months. We included age, gender, allocated group and baseline consumption as covariates and adjusted for the multi-level nature of the study, where young people were nested within EDs.

RESULTS

Conduct problems and to a lesser extent hyperactivity predicted harms at twelve months. This effect was not mediated by alcohol consumed at 6 months.

CONCLUSIONS

Among young drinkers underlying behavioural attributes predict harm independently of alcohol use. This suggests that the harms associated with alcohol use are attributable more to underlying disinhibitory characteristics than the quantity of alcohol consumed.