Construct, concurrent and predictive validity of the URICA: data from two multi-site clinical trials.
BACKGROUND: A better understanding of how to measure motivation to change and how it relates to behavior change in patients with drug and alcohol dependence would broaden our understanding of the role of motivation in addiction treatment. METHODS: Two multi-site, randomized clinical trials comparing brief motivational interventions with standard care were conducted in the National Institute on Drug Abuse Clinical Trials Network. Patients with primary drug dependence and alcohol dependence entering outpatient treatment participated in a study of either Motivational Enhancement Therapy (n=431) or Motivational Interviewing (n=423). The construct, concurrent, and predictive validity of two composite measures of motivation to change derived from the University of Rhode Island Change Assessment (URICA): Readiness to Change (RTC) and Committed Action (CA) were evaluated. RESULTS: Confirmatory factor analysis confirmed the a priori factor structure of the URICA. RTC was significantly associated with measures of addiction severity at baseline (r=.12-.52, p<.05). Although statistically significant (p<.01), the correlations between treatment outcomes and RTC were low (r=-.15 and -18). Additional analyses did not support a moderating or mediating effect of motivation on treatment retention or substance use. CONCLUSIONS: The construct validity of the URICA was confirmed separately in a large sample of drug- and alcohol-dependent patients. However, evidence for the predictive validity of composite scores was very limited and there were no moderating or mediating effects of either measure on treatment outcome. Thus, increased motivation to change, as measured by the composite scores of motivation derived from the URICA, does not appear to influence treatment outcome.