The pre-post treatment change of 112 patients in two therapeutics Spanish communities is described. The Addiction Severity Index (ASI) was used at intake and at the end of the treatment program. Results of the treatment program were evaluated by applying composite scores (CS) of the ASI, and the evolution of each patient was evaluated using the Reliable Change Index (RCI). 69.7% of the sample completed treatment, and 30.3% dropped out prematurely. At intake, the percentage of people who could improve in the different areas of the ASI ranged between 35.1% for alcohol consumption and 95.3% for family relationships. At the follow-up, the percentage of subjects who showed significant statistical improvements in the different areas varied between 7.9% in family relations and 66.7% in alcohol consumption. The percentage of patients who deteriorated was less than 10% for all variables. Implications for further research and clinical practice are commented upon.
