Herbal treatments can be as effective as medications, but they take longer to be effective. For severe mental illness, I would default to medications, and as always, any treatment should be discussed with your doctor. I am not sure how psychiatrists in general feel about herbal medications, though. It might be hard to find one who will work with herbals. The specialist really depends on the preferences of the main psychologist working with the client.
Osteopaths are generally more holistically inclined.
As far as effectiveness, herbal medications work with individual body chemistry and it usually takes at least two weeks for herbal treatments to show effects when treating depression. I have heard 400 mg of Same will work, but then I have heard it must be much much more. I cannot take standard antidepressants, i.e. Prozac, etc., because they upset my colon. I have depression and I need help. First, I would say that it is important to consult with your doctor or an herbal specialist who has your case history.