Trajectories of marijuana use from adolescence into adulthood: Environmental and individual correlates.

Abstract

This study sought to identify trajectories of marijuana use in the Seattle Social Development Project (n = 808) sample from age 14 through 30, and to examine the extent to which individuals in these trajectories differed in their substance use problems, mental health, problem behavior, economic outcomes, and positive functioning at age 33. In addition, analyses examined between-trajectory differences in family, peer, school, neighborhood, individual, mental health, and substance use factors at key developmental points in adolescence and adulthood. Four trajectories of marijuana use were identified: nonusers (27%), adolescent-limited (21%), late-onset (20%), and chronic (32%) users. At age 33, the chronic trajectory was associated with the worst functioning overall. The late-onset group reported more substance use and sexual risk behavior than nonusers, but was otherwise not differentiated. The adolescent-limited group reported significantly lower educational and economic outcomes at age 33 than the late-onset and nonuser groups. In analyses at earlier ages, adolescent-limited and late-onset groups reported more problems in functioning during the period of escalation in use and improvement in functioning with the beginning of desistance. Implications for prevention are discussed, particularly the unique risks associated with early adolescent versus later onset of marijuana use.

Early predictors of maturing out of marijuana use among young men

“…Based on research cited in the conceptual model above, we hypothesize that all of these risk and protective factors will differentiate adolescent monthly marijuana users from nonusers. Conversely, we hypothesize that only lower impulsivity in adolescence will be related to maturing out of marijuana use (Epstein et al, 2015; Labouvie & White, 2002). …”

“…In a study that overcame several of the limitations of previous research, Epstein et al (2015) examined trajectories of marijuana use from ages 14 to 30. They compared a group that used marijuana in adolescence but reduced their use after age 18 and stopped using by age 30 to a group that used similarly in adolescence but escalated their use in young adulthood and continued through age 30; predictors were measured at ages 10–14.…”

The association between regular marijuana use and adult mental health outcomes

“…Many users initiate in adolescence, and some progress from occasional to persistent regular use (Substance Abuse and Mental Health Services Administration, 2013), but the associations between different developmental patterns of regular marijuana use over time and mental health outcomes are not well understood (Bechtold et al, 2015). A recent examination of trajectories of marijuana use from adolescence into adulthood using the present sample examined bivariate relationships between four identified patterns of marijuana users (chronic, adolescence-limited, late-onset, and nonusers) and a host of correlates at different developmental periods (Epstein et al, 2015). That study found mean differences in mental health outcomes at age 33; in general, chronic marijuana users had more symptoms of cannabis, alcohol, and tobacco use disorders than other types of users, and more symptoms of anxiety disorder than nonusers of marijuana.…”

“…Although previous studies that have examined mental health outcomes of long-term marijuana use have focused on empirically derived, probabilistic patterns of use over time (e.g., Bechtold et al, 2015; Epstein et al, 2015), they have not focused specifically on regular use defined by specific a priori criteria. Furthermore, studies of the effects of persistent regular marijuana use (defined as a 5-level variable distinguishing between no use, no regular use, and regular use in 1 through 3 or more assessment points), have been limited to neuropsychological decline (e.g., Meier et al, 2012) and economic and social problems (Cerdá et al, 2016) later in adulthood.…”

Neural mechanisms of sensitivity to peer information in young adult cannabis users

“…It is important to understand motivations for MJ use, as heavy use in adolescence/young adulthood has been robustly linked with harms such as future substance dependence (Berge et al, 2015; Green et al, 2015), worse psychosocial functioning (Lagerberg et al, 2015; Wilkinson, Stefanovics, & Rosenheck, 2015) and worse academic outcomes (Epstein et al, 2015; Meier, Hill, Small, & Luthar, 2015; Silins et al, 2015). Young adults may both initiate and continue to use MJ in part due to social factors.…”