Latent class analysis of discordance between results of drug use assessments in the CATIE data

Abstract

Objective The primary aim is to examine concordant/discordant results of drug use assessments in adults with schizophrenia. Methods Latent class analysis and multinomial logistic regression were used to examine concordance/discordance between drug use measures and identify characteristics differentiating participants across classes. Results Four classes – non-users, users, probable users, and RIA discordant –fit best. Age, sex, race/ethnicity, and psychiatric symptoms differed significantly across classes. Conclusions Findings showed that discordance between results occurs at non-trivial rates and is, in part, attributable to individual characteristics. Results suggest the need for strategies to limit discordance and improve detection of drug use in adults with schizophrenia.

Motivation deficits and use of alcohol and illicit drugs among individuals with schizophrenia

“…Given the potential for under-reported substance use, our findings may underestimate the actual rates of use (Bahorik et al, 2014). Biomedical measures of drug-use had the largest amount of missing data in the CATIE and recent investigations have cautioned that using multiple measures to confirm substance use may result in overestimates (Johnson et al, 2015). Given these concerns and the study design, we believe our use of self-report substance use is appropriate.…”