PSYCHOLINGUISTIC INDICATORS OF MOTIVATION FOR SUBSTANCE USE BEHAVIOR CHANGE AMONG INDIVIDUALS WITH SERIOUS MENTAL ILLNESS

Abstract

The co-occurrence of mental illness and substance use disorders (termed "dual diagnosis") represents a significant public health issue and is associated with significant impairment and negative health consequences, particularly among individuals with serious mental illness. Given the negative consequences associated with dual diagnosis, researchers have sought to identify treatment components that would improve outcomes among individuals with serious mental illness. Therefore, significant efforts have been made to increase motivation for change within severe mental illness populations using Motivational Interviewing, a client-centered therapy. The primary mechanism underlying the effect of Motivational Interviewing on behavior change is hypothesized to be the selective reinforcement of change talk by the therapist with the aim of reducing ambivalence. Change language has been found to predict substance use treatment outcomes; however, it is not clear if change language has similar predictive utility in individuals with serious mental illness. Therefore, the current study sought to validate change language as an indicator of motivation among 45 individuals with serious mental illness and co-occurring substance use disorders. Overall, we found that change language could be reliably coded in this sample. Evidence supported the predictive utility of Ability language (i.e., statements regarding self-efficacy) in prospectively predicting long term substance use treatment outcomes (i.e., six months after the Motivational Interview session) above and beyond negative symptoms, depressive symptoms, and substance use severity. These findings suggest that the investigation of client language during MI represents a promising avenue for understanding motivational processes underlying substance use treatment outcomes among individuals with serious mental illness. Specifically, elicitation of client statements regarding self-efficacy to reduce or stop substance use is particularly important in predicting favorable outcomes in this population. Future studies should evaluate the utility of incorporating treatment components aimed at cultivating self-efficacy for substance use behavior change among individuals with serious mental illness.