This double-blind placebo-controlled pilot study seeks to investigate whether psilocybin can
be safely administered to people with chronic phantom limb pain (PLP) in a supportive setting
with close follow-up, and its effects on pain symptoms and other moods, attitudes, and
behaviors. The investigators' primary hypotheses are that psilocybin is safe to administer in
people with PLP and that it will reduce scores on measures of pain. The investigators will
also assess a number of secondary measures related to the behavioral and neural responses to
pain after psilocybin treatment.