Comorbid Trajectories of Tobacco and Marijuana Use as Related to Psychological Outcomes

ABSTRACT

Heterogeneous classes of comorbid trajectories of tobacco and marijuana use were examined in order to determine how they are related to subsequent antisocial behavior, poor self-control, and internalizing behavior. Data are from a 4-wave longitudinal study of African American (n = 243) and Puerto Rican (n = 232) adolescents and adults in the community. Logistic regression analyses were employed to measure the association between the comorbid trajectories of tobacco and marijuana use and the psychological difficulty variables. The authors found 6 joint trajectory groups. The authors compared the non-or-experimental tobacco/marijuana use group with the other user groups in each of the psychological difficulty domains. The infrequent tobacco/late-onset marijuana use and chronic tobacco/marijuana use groups differed most strongly from the non-or-experimental tobacco/marijuana use group across the antisocial behavior, poor self-control, and internalizing problems domains. The chronic tobacco/maturing out marijuana use group also had significant associations in each of these domains. The infrequent tobacco/marijuana use and late-onset tobacco/infrequent marijuana use groups had no or weak associations with the psychological outcomes. Tobacco and marijuana cessation programs should identify and address comorbid use of tobacco and marijuana, and antisocial behavior, poor self-control, and internalizing problems, which are associated with histories of comorbid use of the 2 substances.

KEYWORDS:

• Comorbidity
• logistic regression analysis
• psychological problems and drug use
• tobacco and marijuana use

Acknowledgments

This work was supported by a Research Scientist Award (DA00244) and a research grant (DA005702) from the National Institutes of Drug Abuse, and by a research grant from the National Cancer Institute of the National Institutes of Health (CA084063). The National Institutes of Drug Abuse and the National Cancer Institute were not involved in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, and approval of the manuscript. The authors thank Dr. Martin Whiteman and David W. Brook, MD, for critical review of the manuscript.