Sixth Version Of The Addiction Severity Index: Assessing Sensitivity To Therapeutic Change And Retention Predictors

The main purpose of this multicenter ex post facto prospective study is to examine the psychometric properties of the Addiction Severity Index version 6.0 (ASI-6) in Spanish outpatients and determine the predictor variables of treatment adherence. A total of 186 outpatients with a substance dependence diagnosis (mean age 40 years; 80% male) were assessed with the ASI-6 and Clinical Global Impression (CGI). Results revealed a moderate decrease in ASI-6 recent summary scores (RSSs) in the Alcohol (I = 4.77; p <= .001), Drug (t = 2.01; p = .035), Psychiatric Status = 5.47; p <= .001) and Family/Social Relationships areas (t = 3.55; p <= .001) from baseline to six months. The adjusted odds ratio (OR) related to an increased probability of adherence was 1.23 for the CGI-S score (95% CI 1.10-1.38). On the contrary, lower adherence was predicted by Severity in the Drug Scale with an OR of .95 (95% CI .92-.98). The Spanish ASI-6 appears to be a valid instrument that is sensitive to therapeutic change, providing relevant and reliable information not only about severity of addiction but also about substance abuse treatment adherence prediction.