Relations Among Adolescent Alcohol and Cannabis Co-Use, Adolescent Impulsive Traits, and Prospective Change in Impulsive Traits into Emerging Adulthood.

Models of personality suggest that adolescent substance use may be associated with adolescent impulsive traits as well as changes in impulsive traits from adolescence into emerging adulthood. However, little research has focused on how adolescent alcohol and cannabis co-use, an increasingly popular and risky substance use pattern, may relate to adolescent impulsive traits as well as changes in impulsive traits from adolescence to emerging adulthood. Therefore, the current study tested patterns of adolescent co-use and their links with adolescent impulsive traits and changes in impulsive traits into emerging adulthood. Data come from the Add Health study and encompassed two timepoints spanning adolescence (age 13-18) and emerging adulthood (age 19-25). A combination of latent profile analysis, mean comparisons, and latent difference scores were estimated. Results suggested that four profiles of co-users and alcohol-only users emerged, and profiles differed in levels of adolescent personality and prospective personality change. Importantly, frequent adolescent co-users had higher levels of adolescent sensation seeking and impulsivity, but also reported the steepest decline in both traits into emerging adulthood. Findings are discussed in terms of personality theory and public health implications.