The theory behind nude psychotherapy is quite logical. It consists about mental disorders giving muscular tensions or the opposite, pathological muscular laxness. By having the patient nude the therapist can look at the body and see much of what is going on in the mental setup, and he can see if the patient makes progress.
This kind of psychotherapy is often combined with special methods of physical therapy that have a combined physical and psychological aim.
But the hysteria of these days have mostly made this kind of therapy a taboo, and even talking about it has become a taboo.
Norway had a tradition of nude psychotherapy combined with physical manipulations, but it was individual therapy, not groupwise. One famous therapist branding this mode was Harald Scheldrup. Many famous patients came to Norway to have sessions with him, among others famous movie stars.
The taboo has reach Norway too, but a remnant of it remains. It is calle Psychomotoric physical therapy, which has the double psychological-physical aim an it is often combined with psychological sessions.
Those performing it has a special education, but they tend to hold much of its methods and theory secret. You cannot find a book to learn it. It is thought only in closed schools.
It is easy to find superficial descriptions aimed to recruit patients, aimed at sending doctors to the therapy, and describing the cooperation with doctors, but little is said about the concrete things done.
I am actively investigating them, though, and some dey I will find their manuals.
I was once sent by a doctor to such a therapy institute. I had one examination session, where I only had on me my underpants. I was asked to get in several poitions and tell what I felt. But when I understood that the therapy was rather expensive I backed out. I never paid the bill for the first session. The therapist did not like that I did yoga. She wanted me only to do exercises she told me to do. This I did not like, which also was a reason why I backed out.
The patient is at least nearly nude during the sessions, and I suspect they sometimes will be completely nude, but I do not know for sure yet.
What I know, though is that the pelvic zone gets much attention during this therapy, and from there the therapy extends to all of the body.
But I am inestigatiing, not because I find nude therapy wrongful, but because I do not like experts holding things secret for the public, and theraby making knowledge a sort of private property they can proffit exsessive from.