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Acute psychological and physiological effects of psilocybin in healthy humans: a double-blind, placebo-controlled dose?effect study

Felix Hasler, Ulrike Grimberg, Marco A. Benz, Theo Huber, Franz X. Vollenweider

Psychopharmacology March 1, 2004 DOI: 10.1007/s00213-003-1640-6 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Randomized controlled trial Placebo-controlled Double-blind Peer reviewed
Sample size 8
Population Healthy human subjects
Intervention Psilocybin
Dose 45, 115, 215, and 315 microg/kg body weight
Topics Psilocybin Serotonin
Keywords Prolactin Endocrinology Placebo Mood Agonist Hormone
Citations 458
Key findings Psilocybin dose-dependently altered consciousness, reduced attention performance by 50% at medium and high doses, and increased plasma prolactin, TSH, ACTH, and cortisol levels without affecting heart rhythm or body temperature.

Abstract

RationaleSerotonin (5-Hydroxytryptamine, 5-HT) receptors play an important role in perception, affect regulation and attention. Pharmacological challenge with the 5-HT(2A) agonist psilocybin (PY) is useful in studying the neurobiological basis of cognition and consciousness.ObjectiveInvestigation of dose-dependent effects of PY on psycho(patho)logical and physiological parameters.MethodsEight subjects received placebo (PL), and 45 ("very low dose, VLD"), 115 ("low dose, LD"), 215 ("medium dose, MD"), and 315 ("high dose, HD") microg/kg body weight PY. The "Altered States of Consciousness Rating Scale" (5D-ASC), the "Frankfurt Attention Inventory" (FAIR), and the "Adjective Mood Rating Scale" (AMRS) were used to assess the effects of PY on psycho(patho)logical core dimensions, attention, and mood. A 24-h electrocardiogram (EKG) was recorded and blood pressure was measured. Plasma concentrations of thyroid-stimulating hormone (TSH), prolactin (PRL), cortisol (CORT), adrenocorticotropic hormone (ACTH), and standard clinical chemical parameters were determined.ResultsPY dose dependently increased scores of all 5D-ASC core dimensions. Only one subject reacted with transient anxiety to HD PY. Compared with PL, MD and HD PY led to a 50% reduction of performance in the FAIR test. "General inactivation", "emotional excitability", and "dreaminess" were the only domains of the AMRS showing increased scores following MD and HD PY. The mean arterial blood pressure (MAP) was moderately elevated only 60 min following administration of HD PY. Neither EKG nor body temperature was affected by any dose of PY. TSH, ACTH, and CORT plasma levels were elevated during peak effects of HD PY, whereas PRL plasma levels were increased following MD and HD PY.ConclusionPY affects core dimensions of altered states of consciousness and physiological parameters in a dose-dependent manner. Our study provided no cause for concern that PY is hazardous with respect to somatic health.

Comparable studies

Other randomized controlled trials on psilocybin, most cited first.

Study Year Design Participants
Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial Cancer patients with life-threatening diagnoses and symptoms of depression and/or anxiety 2016 Randomized controlled trial n = 51
Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial Patients with cancer-related anxiety and depression 2016 Double-blind, placebo-controlled, crossover trial n = 29
Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance Hallucinogen-naïve adults reporting regular participation in religious or spiritual... 2006 Double-blind study n = 36
Trial of Psilocybin versus Escitalopram for Depression Selected group of patients with depression 2021 Randomized controlled trial
Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder Adults aged 21 to 75 years with major depressive disorder, not currently using... 2020 Randomized controlled trial n = 24

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