We have been debating about depression and therapy, medication and what works. I wrote my therapist, PhD, and asked for a list where we could get more info on this subject. Check it out. Lots to learn here whether you are for or against meds, therapy. By the way he is awesome. I wrote last night and had an answer this morning. That is how ya pick a therapist!
Any book covering cognitive-behavioral therapy for depression will have a chapter on efficacy of the treatment (which has been well-documented). Usually it's journal articles that are cited in such documentation of the efficacy of psychotherapy. Typically psychotherapy plus medication is found to be superior to either one alone in terms of duration of improvement and in relapse prevention. Here are a couple of citations I pulled from the Internet:
He went on to say that there are many studies, most technical and in major journals, but many available studies.