I was pleased to see the BCMJ publish Dr Mark Elliott’s piece, “The age of mushrooms is upon us in medicine.” Psychedelics such as LSD and psilocybin showed great promise as investigational tools and, in the case of LSD, as a treatment for addiction, until politics and irrational fears essentially ended all research into these agents for decades. Fortunately, this is changing and a number of studies, as imperfect as they are, suggest that psychedelics, combined with appropriate psychotherapy, may hold great promise in treating end-of-life anxiety, depression, and addiction.

Dr Elliott incorrectly states that psychedelics “seem to affect serotonin and/or monoamine oxidase (MAO) receptors in the brain.” MAO is not a receptor but rather an enzyme that is widely distributed throughout the body (including the CNS). It is generally agreed that the actions of psychedelic agents are primarily mediated through agonism at the 5-HT2A receptor (a class of serotonin receptor) in the brain. I suspect that Dr Elliott was referring to ayahuasca, a plant-derived psychoactive brew containing Banisteriopsis caapi and DMT containing vines (such as Psychotria viridis or Acacia sp). B. caapi contains natural MAO inhibitors that may have some minor CNS effects but act primarily by preventing metabolism of DMT in the gut. This allows the DMT to be absorbed and to exert its effects on the CNS.

Thank you for publishing this otherwise excellent brief overview of the emerging field of psychedelic medicine.
—Jeffrey Eppler, MD
Kelowna

This letter was submitted in response to “The age of mushrooms is upon us in medicine [10].”