Differential Effects of Cognitive Reserve on the Neurocognitive Functioning of Polysubstance Users: an Exploratory Analysis Using Mixture Regression

Abstract

We aimed to identify latent classes based on differential effects of cognitive reserve on neurocognitive variables, and to determine which variables of polysubstance use predict class membership. One hundred sixty-six male participants in residential treatment were recruited in Mexico City and evaluated with Montreal Cognitive Assessment, Tower of Hanoi, Cognitive Reserve Index Questionnaire, and a structured interview for substance use. We performed three independent mixture regression models with cognitive reserve as predictor and neurocognitive variables as outcomes, and we estimated covariate effects of age of onset, years of substance use, and past 30 days of use on class membership. Two class solutions for the three models, all demonstrating differential effects (e.g., for overall cognitive functioning, education seems to serve as a protective factor against impairment for most of the cases, whereas only for some few individuals both education and leisure may protect). No variable of substance use affected the probabilities of membership to latent classes. Individuals at risk of substance-induced neurocognitive impairment may be identified by the association between variables of cognitive performance and cognitive reserve.