As a retired clinical psychologist, Clark Martin was well acquainted with traditional treatments for depression, but his own case seemed untreatable as he struggled through chemotherapy and other grueling regimens for kidney cancer. Counseling seemed futile to him. So did the antidepressant pills he tried.
Nothing had any lasting effect until, at the age of 65, he had his first psychedelic experience. He left his home in Vancouver, Wash., to take part in an experiment at Johns Hopkins medical school involving psilocybin, the psychoactive ingredient found in certain mushrooms.