Depression appears to reduce the effect of peer influence on marijuana use among adolescents participating in two separate studies.
Adolescent Peer Networks and the Moderating Role of Depressive Symptoms on Developmental Trajectories of Cannabis Use
Published in: Addictive Behaviors Volume 76 (January 2018), Pages 34–40. doi: 10.1016/j.addbeh.2017.07.019
Posted on RAND.org on October 13, 2017
Read MoreAccess further information on this document at Addictive Behaviors Volume 76 (January 2018)
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- How do peers affect adolescent use of cannabis?
- Are peer effects moderated by symptoms of depression?
This paper investigated how depressive symptoms moderate the role of peer cannabis use on developmental patterns of individual cannabis use from adolescence to young adulthood, controlling for a broad set of individual and family factors. Data from two sources were analyzed separately: two saturated schools in the National Longitudinal Study of Adolescent to Adult Health Waves I-III (N = 1550) covering 1994–2001; and three schools in the CARBIN study, covering 2012–2014. Discrete mixture models identified developmental trajectories of cannabis use in each data source, and logit models linked network and depressive symptom information to the trajectories. Five similar cannabis use trajectories were identified in both datasets: Nonuse, Low, Moderate, Increasing, and High. Peer cannabis use at baseline predicted higher individual cannabis use trajectories, controlling for a wide range of factors. However, the association between peer cannabis use and higher levels of use (Moderate and High) attenuated as the adolescent's level of depressive symptoms increased. Although these results may suggest that depression dampers adolescents' susceptibility to peer influence, these results are also consistent with the notion that depressed adolescents withdraw from their peer groups, distancing them from the initial source of peer influence over time. The resulting isolation may place adolescents at higher risk of adverse outcomes.
- In two data sets, separated by nearly 20 years, greater cannabis use within a peer network—proportion of friends or quantity of cannabis—was associated with a higher trajectory of cannabis use over time.
- As symptoms of depression increased, however, peer use of cannabis had less effect on the higher use trajectory.
- These results suggest that adolescents with depressive symptoms may be less susceptible to peer influence of cannabis use, but they could also mean that depressed adolescents are less motivated to use cannabis.
Future research should directly examine how changes in peer networks affect substance use behavior among adolescents with depressive symptoms, and vice versa.