Controlling for a number of confounding variables, including MATCH treatment assignment and the intake level of each hypothesized mechanism, attending AA during the first 3 months of the trial was associated with significant subsequent increases in the two social network support mediators and in the two social activity mediators. These results indicate that, over and above the therapeutic impact of the outpatient-delivered MATCH treatments, participation in AA increases network ties associated with abstinence and reduces network ties associated with drinking. It also enhances engagement in abstinent activities and reduces engagement in drinking activities. This pattern of findings was consistent across both the aftercare and outpatient arms of the trial, suggesting AA appears to mobilize adaptive social network and activity changes across individuals exhibiting a broad range of alcohol-related involvement and impairment.
