In a small pilot sample of two older adults with amnestic mild cognitive impairment and three healthy controls, two doses of 25 mg psilocybin given one week apart were safe and well tolerated, with no unexpected or serious adverse events. Expected side effects included dizziness and altered perception, all of which resolved without lasting effects. This double-blind, placebo-controlled randomized study uses PET imaging to measure psilocybin's effect on synaptic density in the hippocampus and prefrontal cortex, and whether changes relate to improved cognition. Preliminary findings support the feasibility of investigating psilocybin in supervised medical settings as a potential treatment for amnestic mild cognitive impairment.
Psychedelic compounds have been used by humans for millennia, originally derived from plants and fungi by ancient and indigenous peoples. Western society was reintroduced to them in the mid-20th century, first through Albert Hofmann's synthesis of LSD in the 1940s and then through Gordon Wasson's introduction to psilocybin mushrooms by Maria Sabina in the 1950s. These substances became subjects of scientific and cultural interest, but their prominence declined sharply in the 1970s due to international drug laws. A resurgence began in the 1990s, leading to an ongoing renaissance in psychedelic science.