"An analysis by researchers at the Norwegian University of Science and Technology found that LSD, hallucinogenic mushrooms and peyote don’t increase one's risk of developing mental health problems. The study also suggested a correlation between the use of psychedelic drugs and fewer mental health problems."
Thus confirming what Dr. John C. Lilly and others knew 50 years ago.
There was ample evidence at the time of positive therapeutic results, albeit under controlled, medically-supervised conditions. Spurious press reports and uninformed government hysteria are what led to the ban.