Changes in neuropsychological functioning over 10 years following adolescent substance abuse treatment

Previously, Anderson, Ramo, Cummins, and Brown (2010) described six distinct patterns of alcohol and other drug (AOD) use during the decade following adolescents' treatment for alcohol and other substance use disorders (A/SUD). This time period represents a phase of significant neurodevelopment, and the influence of substance use on the brain is a concern. In the present study, we examined patterns of neuropsychological function over these 10 years in relation to the AOD trajectories identified for youth as they transition into their twenties. Participants were part of a longitudinal research project following adolescents with and without A/SUD who received neuropsychological examinations at baseline and up to 7 times thereafter spanning 10 years (N = 213; 46% female at baseline). Neuropsychological trajectories were significantly related to substance involvement patterns over time on measures of verbal learning and memory (ps = .011 to <.0001), visuospatial memory (p = .0002), and verbal attention/working memory (p = .020), with heavier use patterns generally followed by poorer cognition. Heavy use of alcohol alone was independently associated with poorer verbal memory over time. Furthermore, substance withdrawal symptoms during each follow-up time point were related to poorer verbal learning and memory scores (ps < .05), whereas substance abuse/dependence diagnostic criteria were not related to neuropsychological performance levels. These findings suggest that AOD use during adolescence and young adulthood may primarily influence performance that relies on later maturing brain structures, although further research is needed. Higher levels of AOD withdrawal symptoms may signify greater neuropsychological impairment, reflecting potential neurotoxic effects of AOD use.