Because the subject is so meaningful to me I will continue to try to answer what I can with what little knowledge I have. I still do not have empirical data or any research results to support my observations; I only have the observations and experiences.
Once again it is my experience that support groups can be invaluable. I have seen people at AA/NA meetings who have attended regularly for 20-30 years, with all those years having been lived clean and sober. I have seen people attending 2-3 times a DAY in order to maintain a tenuous link to sobriety. And after a period of time, 2-3 times a day was no longer necessary, BUT continuing attendance was necessary. There are some who say totally buying into the AA/NA program (which is usually needed to get and stay clean) is just trading one addiction for another. My question to them is which of the 2 addictions (I don't believe total immersion in NA is an addiction) is most destructive? Which of the addictions can result in years of sobriety, complete functioning, lifetime friendships and support and possible happiness, and which one can result in years of suffering and premature death? AA/NA is much like group therapy, which itself has many benefits. There is no downside to trying the program.
I think they learn hope; they find they are not alone in their suffering and addiction; I think they learn techniques for avoiding triggers and for dealing with high-stress situations without having to fall back on the substances they abused. But most importantly they learn there are others willing to help them, to be their anchor in a storm, to be available when they are thinking about picking up. The group dynamic is, I think, undervalued when it comes to issues like addiction. Many times a group dynamic (peer pressure for example) is what initially leads to using. The same dynamic can help to stop using. Oh and by the way, thank you for the 'Thank you'.
Aftercare as part of a treatment program is not the same as support groups. The way I interpreted this excellent question is in terms of self-help groups like 12-Step programs such as AA, NA, CA, etc.). However, there are many alternatives to 12-Step groups. In addition, an addiction can refer to a substance or a behavior. I know I didn't say anything most of us are aware of, but my answer will refer to 12-Step groups for substance dependence.
The early research on 12-Step groups, while positive, most were methodologically flawed and not as accepted by the academic community as the current, better designed studies. A frustration that seemed to run through the recovering community was how clinicians and researchers often did not see 12-Step groups as anything, but an optional adjunct to formal treatment. When former-patients, who regularly attend 12-Step meetings are asked why the program works, a common response is “Because it does.” Many alcohol and other drug dependent people continue to find recovery through AA and NA, and do not feel formal treatment did anything past stabilization. While treatment can be important and even necessary, it is not something we can generalize to everyone. The one most common constant seen in those with long-term recovery is attending AA, NA, or CA. As our methodology became better, those same outcomes were seen, but now with statistical significance.
12-Step groups are effective by themselves and as part of a system of recovery resources. The additive effect of 12-Step attendance, treatment, and intervention at the systems level is showing longer abstinence, better sobriety, and more effective recovery. There is a body of literature attesting to the need for a system approach to addiction prevention and treatment. The best example of that is Recovery Management. I believe that Recovery Management is currently the best hope for long-term treatment of addiction (see the attached monograph).
Research tells us that regularly attending a 12-Step group is effective because of the cognitive-behavioral interventions that happen. Members of those same groups have said it works because one addict or alcoholic is helping another. Most of the members I talk with don’t care why it works. They explained that they follow the 12-Steps as their sponsor instructed, and as long as they do that, they can remain clean and start changing their behavior. Yes, it sounds simplistic, but the 12-Steps are not difficult to understand. The difficulty is in working the steps (that’s a request for someone to respond to the question I posted about that).
Support group is effective because all participants have been there and understand. Also addiction often means being rather alone and we know that social support per se is an effective healing ingredient. When we support each other we
also sort of control each other, in Weight Watchers it works so that those emotional needs we eat, are needs which are more fulfilled by the group and therefore decrease or fall off while the appreciation of the group grows.