Moderators of Intergenerational (Dis)Continuity in Substance Use: A Dual Trajectory Model Approach

There is a well-documented association of intergenerational continuity in substance use between parent and child across adjacent generations. Evidence from multiple, prospective longitudinal studies of multiple generations suggests an important association between parent and child substance use during the same developmental period, notably adolescence. However, recent evidence indicates that when heterogeneity in substance use is accounted for, a considerable amount of discontinuity in behavior from child to parent also emerges. Relatively little is known, however, about moderators of continuity and discontinuity of adolescent substance use across these associations.

This paper merges two existing lines of research—one examining intergenerational continuity in substance use between parent and child with a second investigating parent substance use during the life of the child as a risk factor for onset of adolescent substance use. Using multigenerational, prospective data from the Rochester Intergenerational Study (RIGS), and in line with previous IG studies, we consider prospective data during adolescence (ages 14-18) across both generations to describe developmental trajectories of adolescent marijuana and other substance use in n=264 father-child dyads (father sample primarily African American). We account for heterogeneity in substance use using dual group-based trajectory models which allow for a richer description of continuity and discontinuity. First, we incorporate contemporaneous parent substance use, during the life of the child, to test for moderation of continuity between parent and child substance use. Second, we consider a unique range of measures of contemporaneous parent and other caregiver measures which could function as risk or protective factors. Finally, we seek to establish temporal ordering between the timing of each risk factor and parent developmental history. This allows us to segment the child’s life into different developmental periods (i.e., early childhood, late childhood, early adolescence) to test the differential impact of parental use during each stage conditional on the parent’s developmental history.

Preliminary results indicate that parental substance use at any point during the child’s life increases the probability of the child transitioning to a high or moderate drug use trajectory compared to the low use one, net of parent adolescent history. Although the effect varies in magnitude, in all cases it is significant and positive. Furthermore, this effect on a child transitioning to a chronic group varies by developmental stage, and moderation is strongest when the parent reports using drugs in adulthood. These findings suggest that intergenerational continuity is moderated by parent behavior during the life of the child.