I have been in many forms of group therapy over the years. Some mandatory, some volunteer. I get a lot out the groups in the beginning, but after a while it becomes pretty boring. Honestly if you want to join a group to help your mental health, I would suggest something that interests you to get your mind off things.

I have recently joined a Spirituality group in my area. We gather in a circle and take turns reading positive spiritual affirmations before each group starts. I find it very helpful to my mental health. Yes, I do not know if anyone in the group has a mental illness or bipolar like me, but all we do is promote positive spiritual things and have discussions based on our individual faiths. I find that kind of group greatly beneficial.