The influence of posttreatment mutual help group participation on the friendship networks of substance abuse patients.

The effect of 12-step mutual help groups (e.g., Narcotics Anonymous) on members' friendship networks has received little attention. This 1-year longitudinal study examined such effects in a sample of 2,337 male substance abuse inpatients, 57.7% of whom became significantly involved in 12-step activities (e.g., reading program literature, attending meetings) after treatment. An a priori model of the interplay of 12-step involvement) and friendship networks was tested using structural equation modeling, and found to have excellent fit to the data. Twelve-step group involvement after treatment predicted better general friendship characteristics (e.g., number of close friends) and substance abuse-specific friendship characteristics (e.g., proportion of friends who abstain from drugs and alcohol) at follow-up. Results are discussed in terms of how mutual help group involvement benefits patients and how the self-help group evaluation paradigm should be broadened.