Socioeconomic status, depressive symptoms, and adolescent substance use

To determine the relationships among socioeconomic status (SES), depression, and substance use among teenagers. We hypothesized that, among teenagers, substance use was associated with SES in a graded fashion and that depression is a mechanism through which SES affects substance use behaviors.

Linear regression analyses of cross-sectional data from Wave I of the National Longitudinal Study of Adolescent Health (1995).

Fifteen thousand one hundred twelve adolescents whose parents answered questions assessing household income and parental education.

Use of cigarettes, alcohol, marijuana, and cocaine.

For all 4 substances, frequency of use varied by SES. In the total population, inverse SES gradients were present for cigarette use (education, mean change= -0.052; 95% confidence interval [CI], -0.081 to -0.023; income, mean change= -0.038; 95% CI, -0.069 to -0.007) and alcohol use (income, mean change= 0.044; 95% CI, 0.016-0.071). The relationship between marijuana use and education was also significant but inverse-U-shaped, not linear. This relationship was only present among nonwhite teenagers. Race/ethnicity also moderated the relationships between SES and cigarette use and SES and cocaine use. For cigarette use, stratification by race/ethnicity revealed an inverse graded relationship among white non-Hispanic teenagers and a direct, graded relationship among nonwhite teenagers (ie, mean change for education among white non-Hispanic teenagers, -0.012; 95% CI, -0.016 to -0.075; mean change for education among nonwhite teenagers, 0.040; 95% CI, 0.014-0.072). For cocaine use, a weak, inverse linear relationship existed only between education and cocaine use among white non-Hispanic teenagers (mean change for education, -0.013; 95% CI, -0.026 to -0.0004). The relationship between the SES indicator and substance use weakened when depressive symptoms were entered into the model for the SES-cigarette use relationship (23% decrease in mean change associated with a 1-unit change in both education and income) and for the association between education and cocaine use among white non-Hispanic teenagers (31% decrease).

Socioeconomic status is associated with substance use among teenagers but the nature of the relationship is not consistent across SES indicators or across race/ethnicity groups. Depressive symptoms are a mechanism through which SES affects cigarette and cocaine use behaviors among teenagers. However, these data indicate that interventions targeted toward decreasing depressive symptoms will not have a strong impact on the effects of SES on teenage substance use.