„[…] To me, telling my story gave me an incredible feeling of being accepted by a group. All these awful things I had inside didn’t have to be secrets anymore. When the group accepted my story, all the shame I had melted away.“ — A. A.-participant (Alcoholics Anonymous) 
Being accepted and being able to share stories that one is ashamed of, while experiencing that other people have similar stories to share might bring a strong feeling of togetherness with the group members. An intensification of interpersonal relation within the group, that is. Kama Muta as described here: „[F]inding meaning and coherence in one’s suffering [leads to] finding oneself as a member of a moral community, as part of a larger whole.“ — A. A.-participant 
This might be as well one of the mechanisms of how group therapy can support and help people overcome their addictions and to maintain abstinence.