Socioeconomic disparities in adolescent substance use: Role of enjoyable alternative substance-free activities.

OBJECTIVE: To examine whether reduced substance-free enjoyable activity (i.e., 'alternative reinforcers') is a mediating mechanism linking lower socioeconomic status and adolescent substance use risk.

METHOD: High school students in Los Angeles, CA (N = 2,553, 2013-2014, M age baseline = 14.1) were administered three semiannual surveys. Socioeconomic status was measured by highest parental education reported at Wave 1 (the beginning of 9th grade). Three elements of alternative reinforcement at Wave 2 (six-month follow-up) were assessed as mediators: ratings of frequency of engagement, level of enjoyment, and frequency × enjoyment product scores of substance-free typically pleasant activities (like participation in sports teams or school clubs). Study outcomes included prior six-month alcohol, marijuana, tobacco, and other substance use at Wave 3 (twelve-month follow-up). Logistic regression models adjusting for alternative reinforcers and substance use from the preceding wave as well as other co-factors were used to examine the association of Wave 1 parental education with Wave 3 substance use and mediation by Wave 2 alternative reinforcement.

RESULTS: Lower parental education at Wave 1 was associated with a greater likelihood of reporting alcohol (β = -0.122, 95% CI = -0.234, -0.009) and marijuana (β = -0.168, 95% CI = -0.302, -0.034) use at Wave 3. The inverse association between parental education and substance use was statistically mediated by each element of diminished alternative reinforcement at Wave 2. Lower parental education at Wave 1 was associated with lower alternative reinforcement at Wave 2, which in turn was associated with greater likelihood of alcohol (range of βindirect effects  : -0.007 [95% CI = -0.016, -0.001] to -0.01 [95% CI = -0.018, -0.004]) and marijuana (βs: -0.011 [95% CI = -0.022,-0.002] to -0.018 [95% CI = -0.035, -0.005]) use at Wave 3. Parental education was not associated with use of combustible tobacco products or other drugs at Wave 3 adjusting for Wave 1 combustible tobacco and other drug use, respectively (ps ≥ 0.061).

CONCLUSION: Diminished access to and engagement in substance-free enjoyable activity may in part underlie socioeconomic disparities in adolescent alcohol and marijuana use risk. Increasing substance-free enjoyable activities may be useful in substance abuse prevention in socioeconomically disadvantaged youth.