The impact of stepfamily relationship quality on emerging adult non-medical use of prescription drugs.

BACKGROUND: Emerging adults aged 18 to 25 are most at-risk for non-medical use of prescription drugs (NMUPD). While the literature dedicated to emerging-adult NMUPD has explored risk and protective factors at an individual level, much less is known regarding how interpersonal and familial factors relate to NMUPD. Because interpersonal bonds can have a significant impact on behavior, familial factors may be important predictors of NMUPD among emerging adults.

OBJECTIVES: Inasmuch as growing up in a stepfamily is increasingly common for children, this study aimed to determine whether perceived stepfamily quality within three stepfamily subsystems - child-biological parent, child-stepparent, and child-stepsibling - decreased the likelihood of NMUPD in emerging adulthood.

METHODS: Data came from the Stepfamily Experiences Project (STEP), a retrospective survey examining emerging adults' perceptions of their stepfamily life in 2013. A national quota sampling strategy was used, and the final sample consisted of 902 emerging adults (54.1% female). A structural equation model was constructed, with regression paths from each latent construct predicting the ordinal dependent variable, NMUPD.

RESULTS: Increased retrospective biological parent relationship quality in childhood significantly decreased the likelihood of intensifying NMUPD in emerging adulthood (e.g. moving from the "None" category to the "Once a month or less" category). However, stepparent and stepsibling relationship quality did not influence NMUPD.

CONCLUSION: Findings underscore the importance of the preservation of the child-biological parent relationship within a stepfamily context, and encourage further research on the impact familial systems and subsystems may have on NMUPD.