Exploring the prevalence of substance-induced neurocognitive disorder among polysubstance users, adding subjective and objective evidence of cognitive impairment

Abstract 
The objective of this study was to explore the prevalence of substance-induced neurocognitive disorder (NCD) in a sample of polysubstance users, adding both objective- and subjective cognitive impairment. Method: We collected cross-sectional data from 33 community-based residential facilities in Mexico City. Montreal Cognitive Assessment was used for measurement of objective cognitive impairment, and a DSM-5-based interview for subjective impairment. Years and days of recent use of alcohol, marijuana, cocaine and inhalants were collected for regression analyses. Results: 753 participants were analyzed; from these, 50.5% show objective impairment, 71% and 58.5% self-reported any cognitive deficit and cognitive decline, respectively. Between 21.8%-36.5% would qualify for NCD when integrating both objective- and subjective impairment (deficit or decline). Significant weak associations were found between objective impairment and subjective deficits in all cognitive domains except social cognition. Regression models adding both objective- and subjective measures explained more variation in the years of alcohol, inhalant and cocaine use, and in recent marijuana use, than the objective measure alone, but associations were inconsistent. Conclusion: Though significant in proportion, the prevalence of NCD in this population can only be partially related to substance use. Further integrative approaches are needed to refine the epidemiology of this disorder.