Other similar studies, for example:

DIFFERENTIAL FUNCTIONING OF LAY AND PROFESSIONAL HELPERS. By CARKHUFF, ROBERT R.
Journal of Counseling Psychology, Vol 15(2), Mar 1968, 117-126.

- "EVIDENCE INDICATES THAT WITH OR WITHOUT TRAINING
AND/OR SUPERVISION THE PATIENTS OF LAY COUNSELORS DO
AS WELL OR BETTER THAN THE PATIENTS OF PROFESSIONAL
COUNSELORS."

I recommend reading the research summaries in such books as "The Art of Helping", or "Helping and Human Relations" in so much as they give a long list of research done that details, in part, how dysfunctional professionals can be. I thought this was all known. It can't be a surprise, given all the work that was done in the past to research this.