Beyond risk: Prospective effects of GABA Receptor Subunit Alpha-2 (GABRA2) × Positive Peer Involvement on adolescent behavior

An update on the assessment of culture and environment in the ABCD Study®: Emerging literature and protocol updates over three measurement waves

Advances in our understanding of risk and resilience factors in adolescent brain health and development increasingly demand a broad set of assessment tools that consider a youth's peer, family, school, neighborhood, and cultural contexts in addition to neurobiological, genetic, and biomedical information. The Culture and Environment (CE) Workgroup (WG) of the Adolescent Brain Cognitive Development (ABCD) Study curates these important components of the protocol throughout ten years of planned data collection. In this report, the CE WG presents an update on the evolution of the ABCD Study® CE protocol since study inception (Zucker et al., 2018), as well as emerging findings that include CE measures. Background and measurement characteristics of instruments present in the study since baseline have already been described in our 2018 report, and therefore are only briefly described here. New measures introduced since baseline are described in more detail. Descriptive statistics on all measures are presented based on a total sample of 11,000+ youth and their caregivers assessed at baseline and the following two years. Psychometric properties of the measures, including longitudinal aspects of the data, are reported, along with considerations for future measurement waves. The CE WG ABCD® components are an essential part of the overall protocol that permits characterization of the unique cultural and social environment within which each developing brain is transactionally embedded.

Genetic interactions with stressful environments in depression and addiction

Stress is the most important proximal precipitant of depression, yet most large genome-wide association studies (GWAS) do not include stress as a variable. Here, we review how gene × environment (G × E) interaction might impede the discovery of genetic factors, discuss two examples of G × E interaction in depression and addiction, studies incorporating high-stress environments, as well as upcoming waves of genome-wide environment interaction studies (GWEIS). We discuss recent studies which have shown that genetic distributions can be affected by social factors such as migrations and socioeconomic background. These distinctions are not just academic but have practical consequences. Owing to interaction with the environment, genetic predispositions to depression should not be viewed as unmodifiable destiny. Patients may genetically differ not just in their response to drugs, as in the now well-recognised field of pharmacogenetics, but also in how they react to stressful environments and how they are affected by behavioural therapies.

Longitudinal Links between Adolescent and Peer Conduct Problems and Moderation by a Sensitivity Genetic Index

The most extensively studied influence on adolescent conduct problem behaviors is peers, and the literature points to genetics as one source of individual differences in peer influence. The purpose of this study was to test the hypothesis that an environmental sensitivity genetic index comprised of DRD4, 5-HTTLPR, and GABRA2 variation would moderate the association between peer and adolescent conduct problems. Latent growth modeling was applied to PROSPER project longitudinal data from adolescents and their peers. Results showed the hypothesis was supported; adolescents with more copies of putative sensitivity alleles were more strongly influenced by their peers. The interaction form was consistent with differential susceptibility in follow-up analyses. Strengths and weaknesses of genetic aggregates for sensitivity research are discussed.

A review of psychosocial factors linked to adolescent substance use

PURPOSE

Informed by ecological theories and models of influence, this review discusses various psychosocial risk and protective factors that contribute to adolescent substance use behavior. Given typical patterns of substance use initiation during this developmental period, an emphasis is placed on alcohol, cigarette, and marijuana use.

FINDINGS

Consistent with bioecological theories, peers and parents tend to have the strongest effect on adolescent substance use behavior. Influences can be both direct, such as offers and availability to use substances, as well as indirect influences, such as the perception of substance use approval. Schools and neighborhoods also contribute to adolescent substance use behavior, but this effect is often less direct. Moreover, the effect of neighborhoods on adolescent behavior reflects both structural components (e.g., neighborhood racial composition, teacher-student ratios) in addition to social process (e.g., neighborhood social cohesion, school connectedness). A review of parallel studies conducted with animals is also provided.

SUMMARY

Adolescent substance use behavior does not occur in a vacuum. Investigations must encompass the relevant social ecologies that affect adolescent behavior, including family, peer, school, and neighborhood contexts to provide a more complete understanding of substance use etiology.

Time-varying Effects of GABRG1 and Maladaptive Peer Behavior on Externalizing Behavior from Childhood to Adulthood: Testing Gene × Environment × Development Effects

Engagement in externalizing behavior is problematic. Deviant peer affiliation increases risk for externalizing behavior. Yet, peer effects vary across individuals and may differ across genes. This study determines gene × environment × development interactions as they apply to externalizing behavior from childhood to adulthood. A sample (n = 687; 68% male, 90% White) of youth from the Michigan Longitudinal Study was assessed from ages 10 to 25. Interactions between γ-amino butyric acid type A receptor γ1 subunit (GABRG1; rs7683876, rs13120165) and maladaptive peer behavior on externalizing behavior were examined using time-varying effect modeling. The findings indicate a sequential risk gradient in the influence of maladaptive peer behavior on externalizing behavior depending on the number of G alleles during childhood through adulthood. Individuals with the GG genotype are most vulnerable to maladaptive peer influences, which results in greater externalizing behavior during late childhood through early adulthood.

The Impact of Genes on Adolescent Substance Use: A Developmental Perspective

Purpose

This review discusses the importance of understanding the impact of genetic factors on adolescent substance use within a developmental framework. Methods for identifying genetic factors, relevant endophenotypes and intermediate phenotypes, and gene-environment interplay effects will be reviewed.

Findings

Prior work supports the role of polygenic variation on adolescent substance use. Mechanisms through which genes impact adolescent phenotypes consist of differences in neural structure and function, early temperamental differences, and problem behavior. Gene-environment interactions are characterized by increased vulnerability to both maladaptive and adaptive contexts.

Summary

Developmental considerations in genetic investigations highlight the critical role that polygenic variation has on adolescent substance use. Yet, determining what to do with this information, especially in terms of personalized medicine, poses ethical and logistic challenges.

Child and adolescent predictors of smoking involvement in emerging adulthood

OBJECTIVE

This study examined the differential relationship of externalizing behavior, internalizing behavior, social context, and their interactions to three developmental indicators of smoking involvement: onset (age), amount of smoking, and dependence symptomatology.

METHOD

Participants (n = 504, 73% male) from a high-risk community-based longitudinal study were followed from age 12-14 to young adulthood (18-20). Smoking involvement was conceptualized as a process involving differences in (a) age of onset of smoking, (b) amount of smoking at age 18-20, and (c) level of nicotine dependence symptomatology at age 18-20. Survival analysis was used to predict onset of smoking, regression for smoking level, and zero-inflated Poisson regression for nicotine dependence.

RESULTS

Externalizing (teacher report) and internalizing behavior (youth self-report), prior to the onset of smoking, predicted different components of smoking and nicotine dependence in young adulthood. Parental smoking predicted all levels of smoking involvement. Peer smoking was related to early onset of smoking, but not higher levels of smoking involvement. Externalizing and internalizing behavior interacted to predict nicotine dependence level, with higher levels of internalizing behavior predicting higher levels of dependence symptoms, even at low levels of externalizing behavior.

CONCLUSIONS

Externalizing and internalizing behavior and social context are independent and interacting risk factors that come into play at different points in the developmental process occurring between smoking onset and dependence. This study provides important information for theoretical models of smoking progression and shows that different types of risk should be targeted for prevention at different points in smoking progression. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Developmental Change in Adolescent Delinquency: Modeling Time-Varying Effects of a Preventative Intervention and GABRA2 Halpotype Linked to Alcohol Use

Better integrating human developmental factors in genomic research is part of a set of next steps for testing gene-by-environment interaction hypotheses. This study adds to this work by extending prior research using time-varying effect modeling (TVEM) to evaluate the longitudinal associations between the PROSPER preventive intervention delivery system, a GABRA2 haplotype linked to alcohol use, and their interaction on adolescent delinquency. Logistic and Poisson analyses on eight waves of data spanning ages 11 to 19 (60% female, 90% Caucasian) showed the intervention reduced delinquency from ages 13 to 16. Moreover, interaction analysis revealed that the effect of the multicomponent intervention was significantly greater for T-allele carriers of the GABRA2 SNP rs279845, but only during the 13 to 16 age period. The results are discussed in terms of adolescent delinquency normativeness, implications for preventive intervention research, and the utility of incorporating development in GxE research.

Pathways to Youth Behavior: The Role of Genetic, Neural, and Behavioral Markers

Neural and temperamental mechanisms through which a genetic risk marker in the γ-amino butyric acid α2 receptor subunit (GABRA2) impacts adolescent functioning were investigated. Participants (N = 80; 29 female) completed an emotional word task during functional magnetic resonance imaging. Behavioral control, negative emotionality, and resiliency temperament constructs were assessed. Externalizing and internalizing problems were the outcomes. Those with the GABRA2 minor allele had reduced activation to positive words in the angular gyrus, middle temporal gyrus, and cerebellum, and to negative words in frontal, parietal, and occipital cortices. Reduced activation in the angular gyrus predicted greater negative emotionality and, in turn, elevated externalizing problems. Reduced activation in the inferior parietal cortex predicted greater resiliency and, in turn, low externalizing problems.