Acute psychological and physiological effects of psilocybin in healthy humans: a double-blind, placebo-controlled dose?effect study
Psychopharmacology March 1, 2004 Felix Hasler, Ulrike Grimberg, Marco A. Benz et al. 458 citations
Psilocybin, a serotonin 5-HT(2A) receptor agonist, dose-dependently altered consciousness, attention, and mood in eight healthy subjects. At medium and high doses (215 and 315 micrograms per kilogram body weight), performance on an attention test dropped by 50%, and participants reported increased emotional excitability, dreaminess, and general inactivation. Only one person experienced transient anxiety at the highest dose. Blood pressure rose modestly after the high dose, and levels of the hormones TSH, ACTH, cortisol, and prolactin increased during peak effects, with prolactin rising after both medium and high doses. No changes occurred in heart rhythm or body temperature. The authors conclude psilocybin affects core dimensions of consciousness and physiology in a dose-dependent manner and found no evidence of harm to physical health.