Longitudinal relations between substance use abstinence motivations and substance use behaviors in adolescence: A self-determination theory approach

Objective We employed self-determination theory (SDT) as a framework for examining longitudinal relations between adolescents' motivations to abstain from substances and their subsequent substance use. Method Participants were 475 adolescents in the United States. The data came from annual surveys following adolescents from age 16 to 19. The measures included self-reports of controlled and autonomous motivations to abstain from substances, as well as substance use frequency. Results We used structural equation modeling to estimate autoregressive cross-lagged models of controlled and autonomous abstinence motivations predicting substance use a year later (with 3 years of data on abstinence motivations and 4 years of data on substance use). Autonomous motivation predicted decreases in substance use, while controlled motivation predicted increases. Follow-up analyses also revealed that relations between abstinence motivations and substance use increase in strength with greater time lags, and decreases in autonomous abstinence motivation partially mediate the link between controlled abstinence motivation and later substance use. Conclusions This study demonstrated the usefulness of SDT in understanding motivations to abstain from substance use during adolescence. In line with this theoretical approach, autonomous motivations for abstinence were adaptive while controlled motivations for abstinence were maladaptive.