Grade-Level Differences in the Profiles of Substance Use and Behavioral Health Problems: A Multi-Group Latent Class Analysis.

We investigated associations between polysubstance use and behavioral problems among adolescents. Because substance use becomes more developmentally normative with age, we examined whether polysubstance use was less likely to co-occur with behavioral problems among older (vs. younger) adolescents. Using data from a nationally representative survey of US high school students, we compared the association between polysubstance use (i.e., use of alcohol, cannabis, tobacco/nicotine, and illicit drugs) and behavioral problems (i.e., suicide attempts, depressive symptoms, poor school performance, and sexual risk behaviors) by grade level. We conducted latent class analysis (LCA) to characterize patterns of polysubstance use, and multi-group LCA to estimate invariance by grade. Among the three latent classes that emerged, classes were distinguished by having low, moderate, and high probabilities for behavior problems and use of substances. Class I comprised 52% of the sample, whereas classes II and III comprised 35% and 12% of the sample, respectively. The multi-group LCA showed that younger adolescents had a higher relative probability of co-occurring problem behaviors and polysubstance use. Findings may be helpful in targeting screening and prevention efforts of high school students by grade. Specifically, our results provide evidence that associations between behavioral problems and alcohol/drug use are weaker in later high school grades, suggesting that substance use may not be a weaker marker of behavioral problems for students in higher grades.