Resumo do estudo

Eighteen healthy subjects underwent a double-blind, between-group, randomized placebo-controlled trial to test whether the previous findings on the effects of psilocybin occur in a dose-dependent manner. In one-month intervals, subjects received psilocybin doses either in ascending or descending order, along with a placebo (0, 5, 10, 20, 30 mg/70 kg). Acute and persisting effects were measured immediately after and one month after each session, with a follow-up at fourteen months. At the two highest doses, psilocybin produced effects such as extreme anxiety and fear (39% of subjects) and/or mystical experiences in 72% of subjects. With greater positive effects at higher doses, subjects attributed their substantially significant psilocybin experience to positive changes in attitudes, mood and behaviour, while these ratings did not change after 14 months.