Predictors of Illicit Marijuana Use Among a National Sample of Adolescents: The Impact of Poverty, Race, and Gender

Background and Purpose:  Marijuana is frequently used by adolescents, and perceived risk of marijuana use has been consistently decreasing in this age group.  Early substance use has been associated with mental health, social, and legal problems, which are predictive of decreased rates of high school graduation, participation in higher education, and employment in adulthood.  Social disadvantage (factors associated with low social status), such as female gender, racial/ethnic minority status, or living in poverty, has been postulated to contribute to substance use but it is not known how it impacts adolescent marijuana use.  Thus, this project sought to explore whether poverty, racial minority status, or female gender were predictive of illicit marijuana use in a large, nationally representative sample of adolescents.  

Methods:  Hierarchical logistic regression was used to test a model predicting illicit marijuana use in a nationally representative sample of 14-17 year olds (N = 13,125).  Secondary data from the NSDUH were used for this study.  The model included gender, poverty, and race as well as other risk and protective factors, including age, history of anxiety, history of depression, school performance, enjoyment of school, parental attitudes toward substance use, parental monitoring/involvement, peer acceptance of substance use, peer illicit substance use, and perception of marijuana-related risk. 

Results:   The total model accounted for over 50% of the variance in marijuana use. Female gender and poverty were significant predictors until parental and peer variables were added to the model, indicating potential mediation.  Indirect effects of gender and poverty via parental and peer attitudes toward substance use were tested using bootstrapped 95% confidence intervals with 1000 resamples of the data; parental and peer attitudes toward substance use  mediated the relationships between gender and marijuana use and between poverty status and marijuana use.  In the final model, Latino race, anxiety, depression, and higher age, parental disapproval of substance use, and perceived risk of use predicted increased odds of marijuana use.  Higher school performance, peer disapproval, peer substance use, and parental monitoring predicted decreased odds of marijuana use.

Conclusions and Implications:  Although prevention efforts should be targeted toward all adolescents, these findings inform prevention specialists which populations might need specifically targeted.  Significant indirect effects have implications for how prevention programs might intervene to impact marijuana use for at-risk adolescent groups.  Also, the finding that higher perceived risk was associated with increased odds of marijuana use has implications for the current state of prevention efforts used in many parts of the U.S.; fear-based programs that rely on information about marijuana-related consequences have repeatedly been found to be an ineffective deterrent for adolescents and the current research supports this finding.  Along with information about further implications for practice and policy, limitations of this research and suggestions for future research will be discussed, including the need for longitudinal research since time-order cannot be established in this cross-sectional dataset.