Psychedelic experience sources of some psychedelic drugs such as ayahuasca and mescaline-containing cacti are sometimes referred to as "plant teachers". Similarly, in a follow-up to the psilocybin and mysticism study at Johns Hopkins, researchers observed that psilocybin: "occasions personally and spiritually significant mystical experiences that predict long-term changes in behaviors, attitudes and values". Psychedelic experience includes the full range of mystical or religious experiential phenomena. Two scientific studies have concluded that psilocybin (a typical psychedelic compound that occurs naturally in psilocybin mushrooms) reliably triggers mystical-type experiences. The more recent study at Johns Hopkins University identified mystical experiences by means of several questionnaires
Mescaline deemed too controversial and ultimately omitted from the show, Mayhew praised the experience, calling it "the most interesting thing I ever did". Mescaline has a wide array of suggested medical usage, including treatment of alcoholism and depression. However, its status as a Schedule I controlled substance in the Convention on Psychotropic Substances limits availability of the drug to researchers. Because of this, very few studies concerning mescaline's activity and potential therapeutic effects in humans have been conducted since the early 1970s. Mescaline is biosynthesized from tyrosine or a hydroxylated phenylalanine. In "Lophophora williamsii" (Peyote), dopamine converts into mescaline in a