The first paper uses longitudinal data from 387 adolescents (aged 10-12 years at baseline) to model heterogeneous trajectories of common drug use from early-mid adolescence and examines linkages between early patterns of use and later risk for substance dependence in young adulthood (ages 18-22). Findings suggest that early progression in drug use during adolescence, as opposed to early experimentation, predicts later dependence. Further, early progression in drug use was predicted by individual differences in impulsivity, that were linked to pre-existing weaknesses in working memory, assessed during pre-adolescent years. Findings suggest that interventions to reduce adverse drug use outcomes should focus preventatively on weaknesses in self-control at earlier ages.
The second paper evaluates the factor structure of impulsivity and examines the role of different dimensions of impulsivity in predicting substance use and dependence outcomes during young (18-25 years) and middle adulthood (25-40 years). A three-factor solution representing impulsive trait, impulsive action, and impulsive choice emerged as the best fitting model for both young and older adults. The impulsive trait factor was significantly associated with alcohol and drug dependence in both groups, while the impulsive choice factor predicted alcohol dependence only. Further, in the case of older adults, impulsive action was also associated with greater drug use. Findings support the multidimensionality of impulsivity and its predictive validity for drug use outcomes across the lifespan.
The third paper advances our understanding of the neuropsychological bases for individual differences in impulsivity by examining its relation to executive functioning. Specifically, using three waves of longitudinal data from typically developing adolescents, the authors find that changes in impulsive action (acting-without-thinking) are better predicted by executive attention (i.e., ability to maintain and flexibly switch attentional focus), whereas changes in impulsive choice (delay discounting) are better predicted by the broader factor of working memory ability. Given that these effects remained significant after controlling for more pervasive influences of SES and age suggests that cognitive training interventions may hold promise as a preventive approach to reducing adverse effects of adolescent impulsivity.