ECPN Student Poster Contestant: The Age-Varying Associations Among Parental Monitoring, Affiliation with Deviant Peers, and Adolescent Substance Use

Adolescent substance use is related to various negative outcomes such as impaired judgment and performance, abnormal brain development, addiction, mental health problems, and mortality. Past research underscores the importance of parent and peer relationships for adolescent substance use risk. However, the developmental timing and relative strength of parent and peer influence on substance use is less well understood.

The present study examined the age-varying associations among parental monitoring, affiliation with deviant peers (ADP), and adolescents’ past-month substance use (cigarettes, alcohol, and marijuana) using time-varying effect modeling (TVEM), which facilitates discovery of complex (i.e., non-linear) change in regression coefficients through spline-based modeling. The present longitudinal study followed adolescents (N=7498, 50.25% female) from age 11 to age 18.

Analyses revealed that adolescents reported steady increases in past-month use of cigarettes, alcohol, and marijuana across adolescence, starting from very low rates of use (< 5%) at age 11 to moderate rates of use by age 18 (cigarettes: 32%; alcohol: 54%; marijuana: 21%). Small but statistically significant gender differences in past-month substance use rates were observed.

In the cigarette use model, low parental monitoring was associated with cigarette use across adolescence. This association was strongest at age 11 (OR = 1.8) and gradually declined to non-significance at age 18. ADP was significantly associated with cigarette use across all ages, showing an inverted-U shaped curve peaking at around age 14 (OR = 2.3).

Regarding alcohol use, low parental monitoring was significantly associated with alcohol use across all ages (OR = 1.7 at age 11), although the magnitude decreased slightly with age. ADP had a stable association with alcohol use across adolescence (OR ≈ 1.8).

Low parental monitoring had a significant association with marijuana use across all ages, with the strongest association at age 11 (OR = 2.9). This association decreased in magnitude from age 11 to 14, and maintained a small but significant association through age 18. ADP exhibited a curvilinear trend in which the magnitude of association with marijuana was lowest (and non-significant) at age 11, with rapid increases in magnitude seen by age 13 (OR = 2.6), followed by a gradual decline from 13 to 17.

Parental monitoring and ADP were strongly associated with substance use and the associations varied as a function of age. Negative peer influence appears to have a stronger association with substance use than parental monitoring beginning around age 13. Findings highlight the most promising ages to target particular mechanisms in prevention and intervention efforts for adolescent substance use.