In Project MATCH (Project MATCH Research Group, 1993), patients that had heavy drinking social networks at the start of treatment who were randomly assigned to a treatment designed to facilitate AA participation (i.e., Twelve-Step Facilitation [TSF]) had better long-term outcomes after three years than patients assigned to either a cognitive behavioral or motivational intervention. This treatment matching effect was partially mediated by AA attendance during the 3-year follow-up period (Longabaugh et al, 1998, 2001). This matching effect was not observed at the 1-year follow-up on measures of alcohol use. However, a further analysis of Project MATCH data examined this same attribute by treatment interaction matching effect but on 1-year post-treatment alcohol-related consequences using growth mixture modeling. Results from this analysis once again revealed greater benefit for outpatients assigned to TSF, but in this case at 1 year post-treatment (Wu and Witkiewitz, 2008).
