This study goes beyond its predecessors by employing prospective longitudinal data from a community sample in order to (1) assess the developmental patterns of substance use and SUDs, including a gender comparison, and (2) examine whether comorbidity across substances as well as the progression from use to SUD support a generalized versus substance-specific model of liability for alcohol, tobacco, and marijuana related problems. Furthermore, it adds to the limited number of studies that have explored the comorbidity between substances across developmental stages. Significant age trends confirm that alcohol, tobacco, and marijuana use and SUDs are developmental phenomena which increase gradually with age. Risk models suggest that while being exposed to a particular substance in adolescence increases the risk for problems with the same substance later in young adulthood, the risk is also elevated once there is involvement with other substances. Lastly, the magnitude of substance-specific risk differs between substances; tobacco confers the greatest degree of risk of a SUD diagnosis followed by marijuana and alcohol.
