Psychiatrist John Halpern discusses the psychotherapeutic potential of peyote, ayahuasca, psilocybin, MDMA and other psychedelics By John Horgan on July 10, 2017 I first met psychedelic expert John H. Halpern, M.D., in 1999 at a conference on altered states in Basel, Switzerland (where I also interviewed Albert Hofmann, LSD’s discoverer, and tripped on magic mushrooms). […]