Yes, countless patients have prayed for health, or been prayed for, and then recovered, but countless prayers have not yielded the hoped-for results.
As a philosophy professor wrote: "The fact that a person feels that a prayer was heard by a spirit is not proof that there was an intervention. A baseball fan may cross his fingers and hope a batter gets a hit, but if the batter does or doesn't get a hit, the fan's feelings are not relevant to whether the superstitious action had any effect on the batter's performance."
Faith will not treat schizophrenia, prayer will not alleviate bipolar disorder, belief will not ameliorate Alzheimers, spirituality will not conquer clinical depression. Relying on religion without resorting to medical intervention is lunacy.
Rabbi Mark S. Miller
Temple Bat Yahm
It depends on the nature of the mental health problem, the qualifications of the clergy, the availability of other resources, and the client's motivation to develop or apply spiritual values. I have a private practice as a psychotherapist and pastoral counselor, one of the few professions which offer specialization in the integration of spirituality and psychology.
Pastoral counseling programs are often interfaith, and certification requires at least a master's in psychology, a master's in theology, and clinical supervision. However, most clergy do receive basic training in seminary to respond to common concerns such as marital problems, parenting issues, depression and grief, and they can provide brief therapy as well as make good referrals where ongoing professional help is needed.