The impact of polygenic risk, parental separation, and parental relationship discord on heavy episodic drinking across adolescence and young adulthood in a high-risk sample

Objective. Parental separation and parental relationship discord are cross-sectionally associated with alcohol use behaviors in youth and adults, but less is known about whether and how parental separation and discord are associated with the longitudinal course of alcohol misuse behaviors (i.e., trajectories), and how these family stressors interact with genetic predispositions. The purpose of this project was to examine how the longitudinal course of heavy episodic drinking across adolescence and young adulthood varied as a function of polygenic risk, parental separation, and parental relationship discord.Methods. Participants included genetically inferred continental groups of European (EA, N=1761) and African (AA, N=894) American from the Collaborative Study on the Genetics of Alcoholism (COGA) Prospective sample who were reassessed biennially (M = 4.65 assessments). Alcohol misuse was indexed by frequency of heavy episodic drinking during the past year. Predictors included parental separation, parental relationship discord, and problematic alcohol use polygenic scores (PGSPAU). Data were analyzed with linear mixed effects growth models. Results. Heavy episodic drinking frequency increased between adolescence and young adulthood and then decreased. Among EA participants, parental separation was associated with heavy episodic drinking intercepts, but was not related to linear slope or quadratic curvature of the course. Higher PGSPAU was associated with a faster initial growth and slower decline in the longitudinal course of heavy episodic drinking. Among AA participants, parental relationship discord was not associated with heavy episodic drinking at baseline but was associated with a faster initial growth and slower decline later on. No interaction was found between PGSPAU and parental separation and discord for predicting heavy episodic drinking trajectories in either EA or AA samples. Discussion. Genetic risk and exposure to parental separation and discord are associated with the course of heavy episodic drinking trajectories from adolescence through young adulthood, with some differences across continental groups.