Although lower socioeconomic status has been linked to increased youth substance use, much less research has determined potential mechanisms explaining the association. The current longitudinal study tested whether alternative (i.e., pleasure gained from activities without any concurrent use of substances) and complementary (i.e., pleasure gained from activities in tandem with substance use) reinforcement mediate the link between lower socioeconomic status and youth substance use. Further, we tested whether alternative and complementary reinforcement and youth substance use gradually unfold over time and then intersect with one another in a cascading manner. Potential sex differences are also examined. Data were drawn from a longitudinal survey of substance use and mental health among high school students in Los Angeles. Data collection involved four semiannual assessment waves beginning in fall 2013 (N = 3395; M baseline age = 14.1; 47% Hispanic, 16.2% Asian, 16.1% multiethnic, 15.7% White, and 5% Black; 53.4% female). The results from a negative binomial path model suggested that lower parental socioeconomic status (i.e., lower parental education) was significantly related to an increased number of substances used by youth. The final path model revealed that the inverse association was statistically mediated by adolescents' diminished engagement in pleasurable substance-free activities (i.e., alternative reinforcers) and elevated engagement in pleasurable activities paired with substance use (i.e., complementary reinforcers). The direct effect of lower parental education on adolescent substance use was not statistically significant after accounting for the hypothesized mediating mechanisms. No sex differences were detected. Increasing access to and engagement in pleasant activities of high quality that do not need a reinforcement enhancer, such as substances, may be useful in interrupting the link between lower parental socioeconomic status and youth substance use.
Keywords: Adolescents; Behavioral economics; Cascade model; Health disparities; Socioeconomic status; Substance use.