This study (1977; n=34) found that peak experiences may be an important factor in determining the efficacy of DPT-assisted psychotherapy for cancer patients.
From the conclusion of the paper:
“In conclusion, it may be observed that peak experiences may constitute an intrinsic element of effective psycho therapy for some persons. The explicit causative role of such unique experiences in contributing to psychotherapy in general still constitutes an intriguing research question; the correlation of such experiences with rapid therapeutic progress in the course of short-term psychotherapy with cancer patients, however, is indicated by this study. Clinical impressions would suggest that, when a peak experience does occur, its continuing relevance for daily living may be strongly dependent on the degree to which the associated insights are assimilated or transferred into the everyday self-concept and world view of the patient.”
Authors: William A. Richards, John C. Rhead, Francesco B. Dileo, Richard Yensen & Albert A. Kurland