The role of parental illicit substance use and interparental conflict frequency on children's externalizing behaviors over time

Parental illicit substance use is associated with increases in both interparental conflict frequency and children's externalizing behaviors. There is a paucity of research examining the pathways linking these constructs. Assessing parental illicit substance use and interparental conflict frequency simultaneously can illustrate a process that potentially undermines children's behavioral adjustment. Using a sample of stable, long-term couples and their children from the Future of Families and Child Wellbeing Study (n = 1,011), the current study used path modeling and a multi-informant approach to examine the link between parental substance use and children's later externalizing behaviors and if interparental conflict frequency mediated this association. Results indicated that parental substance use, assessed at the couple-level, was not associated with children's later externalizing behavior, nor did interparental conflict frequency mediate this association. Post-hoc exploratory analyses found that mothers' substance use was associated with children's later externalizing behaviors, and this effect was stronger than fathers' substance use, which was not associated with children's later functioning. These results highlight the importance of examining how various aspects of substance use and different dimensions of interparental conflict might differentially impact children's outcomes.