Introduction: This longitudinal study examined the psychosocial factors associated with the comorbidity of pairs of tobacco and marijuana use trajectories from adolescence extending into adulthood in two ethnic groups, Blacks and Puerto Ricans.
Methods: Data on psychosocial functioning and tobacco and marijuana use at four points in time were obtained.
Results: The association between the trajectories of tobacco and marijuana use was quite high. Pairs of comorbid trajectories of tobacco and marijuana use may share at least three kinds of influence: (a) a constellation of externalizing personality risk factors, (b) Depressive Mood and low Ego Integration, and (c) identification with certain group values.
Discussion: Knowledge of the risk and protective factors for pairs of comorbid trajectories of use may strengthen the foundation for individual and group targets for prevention and treatment programs.