Evaluation of Treatment Programs for Dual Disorder Individuals: Modeling Longitudinal and Mediation Effects

This study evaluated the effectiveness of the three approaches for treating dual disorder clients who were homeless at intake: integrated assertive community treatment (IACT), assertive community treatment only (ACTO), and standard care (SC). Multilevel Random Coefficient Modeling (MRCM) was used to analyze longitudinal effects and to identify mediators of significant treatment effects. The outcome variables were consumer satisfaction, stable housing, psychiatric symptoms, and substance abuse. The eight mediators were service utilization variables: program contacts, phone contacts, substance abuse contacts, assistance with activities of daily living, transportation assistance, help finding permanent housing, help with emotional problems, and medication assistance. The 191 eligible participants were randomly assigned to one of the three conditions and followed for a period of 30 months. Both ACTO and IACT produced better outcomes than SC on consumer satisfaction and stable housing. There were no differences on any of the outcome variables between ACTO versus IACT when comparing main effects. However, there were several treatment by time interactions. In addition, there were many mediation effects.