There’s a really easy way to tell whether a mental health treatment is likely effective. If, when the treatment fails, the person gets blamed then the treatment’s effectiveness should be seriously called into question. For example religion often makes all these extravagant promises and then when they don’t come to fruition the person shoulders the blame for not “having enough faith”. Same with faith-based recovery group, if you fail you aren’t “letting go and letting God/working the steps” well enough. Non religious treatments do this too, like the “power of positive thinking” pop psychology, if the person isn’t recovering it’s because they just aren’t thinking enough positive thoughts.
Underlying all of this is the fact that all the effective treatments for mental illness are expensive. Most people without money or who grew up without money will refer people to the religion or pop psychology based treatments because they can’t afford anything else. They’ll refer people with mental health problems to pastors (who have no training dealing with the mentally ill) instead of trained mental health professionals. They generally don’t do this out of spite but out of ignorance. Religion and faith-based recovery group’s extravagant promises of recovery tend to hook people in the same way those “Down Payment Fairy” ads get poor people to buy homes they can’t afford.