RESUMO
Can positive transitions into young adulthood at age 25 prevent problematic substance use at age 31, even in the context of childhood adverse family environments, conduct problems, and adolescent substance use? We lean on John Schulenberg's developmental framework to examine this question, focusing on the potential young adult milestones of high school and college graduation, employment, residential independence, romantic partnership, and parenthood. Data came from a prospective-longitudinal multi-method study with N = 1199 participants who were first assessed at age 5 years old and followed to age 31. An accumulation of positive transitions in young adulthood (age 25) was associated with lower likelihood of age 31 problematic cannabis use. The protective effect for problematic cannabis use remained even when adjusting for childhood adverse family environments and was primarily driven by successful college graduation and/or home ownership. The accumulation of positive transitions protected individuals at modest to somewhat elevated risk due to childhood adverse family environments from experiencing age 31 cannabis use problems. However, for other individuals with very high numbers of conduct problems, or with high levels of adolescent substance use, the protective effects of accumulated positive transitions to young adulthood were less strong or nonexistent. Moreover, individuals who completed college or obtained full-time employment by 25 were more likely to report problematic age 31 alcohol use. These findings highlight the central tenets of John Schulenberg's developmental framework, including the examination of ontogenetic continuity and discontinuity, the interplay of developmentally distal and proximal effects, and the identification of developmental protective factors that may sway people toward or away from substance use.