Originally Posted by
doorknob 
People with mental health problems tend to have a harder time with sobriety, so that may not be specific to 12-Step participation. However, I think it's a no-brainer that people with religious/spiritual beliefs will be more successful with AA/NA, since, like a good luck charm or sugar pill, it's not gonna work if you don't believe it's going to.
Yes, people with MH issues do have a harder time. It's tough to treat two things at once and psychiatry is so hit and miss (which meds/combo of meds) is going to work, not to mention the fact how much time can be spent trying to find this out, and then the task becomes enduring sobriety long enough so that meds can kick in and avoiding picking up before that point, which can be hard. And of course, if one is predisposed to religious beliefs AA will be up their alley, as you point out.