Twenty-one controlled studies including approximately 7000 participants (10 randomised controlled trials (RCTs) and 11 non-RCTs).
Effect sizes:
1. RCTs of conventional AA meetings.
Overall (n=5) -0.54 (95% CI: -0.98, -0.11; p<0.05).
AA vs. no treatment (n=2) -0.25 (95% CI: -0.54, 0.05).
AA vs. alternative treatment (n=3) -0.61 (95% CI: -1.31, 0.10).
2. Non-randomised studies of conventional AA meetings.
Overall (n=10) 0.40 (95% CI: 0.19, 0.61; p<0.05).
Attended vs. not (n=7) 0.39 (95% CI: 0.11, 0.66; p<0.05).
Attended more vs. less (n=2) 0.55 (95% CI: 0.27, 0.82; p<0.05).
Attended vs attended plus treatment (n=1) 0.27 (95% CI: -0.18, 0.71).
3. RCTs of AA residential treatments.
Overall (n=2) 0.39 (95% CI: -0.16, 0.95).
4. Non-randomised studies of AA residential treatments.
Overall (n=2) 1.33 (95% CI: 0.28, 2.39; p<0.05).
5. RCTs of components of AA programme (i.e. dismantling studies).
Overall (n=5) 0.38 (95% CI: 0.13, 0.63; p<0.05).
Three studies looked at the use of recovered alcoholic counsellors (vs. non-alcoholic counsellors) 0.31 (95% CI: 0.03, 0.59); and two studies at training participants in the AA twelve steps or the AA honest inventory (vs. discussion groups, hypnotherapy, or pharmacotherapies) 0.54 (95% CI: 0.16, 0.92).
Study quality and methodological issues:
The results from the non-randomised studies (vs. RCTs) of conventional AA meetings showed significantly larger more positive results (chi-squared=14.56, df=1, p=0.0001). Studies that used collateral reports to check outcome status yielded non-significantly smaller effect sizes (0.10, 95% CI: -0.32, 0.53) than when no collateral checks were used (0.49, 95% CI: 0.18, 0.81). However, the pooled effects sizes were not significantly different when the analyses were repeated using only collateral reports. For pooled effects sizes of conventional AA meeting data all of the RCTs used coerced participants while 8/9 of the non-randomised studies used volunteers. Therefore volunteer-coercion status was nearly completely confounded with non-random-random assignment for conventional AA meetings. Some of the other studies reported in the review also used a mixture of volunteers and coerced participants, which may bias their findings.