Lagged mediation model* of the effects of 12-step meeting attendance (3 m) on social network changes (6 m) and PDA and PDHD (12 m).

*All models controlling for predictors of attrition (education), baseline levels of Percent Days Abstinent (PDA)Percent Days Heavy Drinking (PDHD), baseline levels of the mediator, and predictors of PDA/PDHD (age, gender, commitment to sobriety, motivation, prior hospitalization for alcohol/drug problems and meeting with other mutual help group members outside of meetings at baseline).