Effects of psilocybin on time perception and temporal control of behaviour in humans

• Published in: Journal of psychopharmacology (Oxford) Vol. 21; no. 1; pp. 50 - 64
• Main Authors: Wittmann, Marc, Carter, Olivia, Hasler, Felix, Cahn, B. Rael, Grimberg, Ulrike, Spring, Philipp, Hell, Daniel, Flohr, Hans, Vollenweider, Franz X.
• Format: Journal Article
• Language: English
• Published: Thousand Oaks, CA Sage Publications 01-01-2007; Sage; Sage Publications Ltd. (UK); Sage Publications Ltd
• Subjects: Adult; Analysis; Analysis of Variance; Biological and medical sciences; Brain; Clinical trials; Consciousness; Depersonalization - chemically induced; Dopamine Agonists - adverse effects; Dopamine Agonists - pharmacology; Dose-Response Relationship, Drug; Double-Blind Method; Female; Hallucinogens; Hallucinogens - adverse effects; Hallucinogens - pharmacology; Health aspects; Health behavior; Humans; Male; Medical sciences; Memory - drug effects; Mushrooms, Hallucinogenic; Neuropharmacology; Perceptions; Periodicity; Pharmacology; Pharmacology. Drug treatments; Psilocybin - adverse effects; Psilocybin - pharmacology; Psychomotor Performance - drug effects; Reference Values; Serotonin 5-HT1 Receptor Agonists; Serotonin 5-HT2 Receptor Agonists; Space Perception - drug effects; Time; Time Factors; Time Perception - drug effects; United States; Switzerland; 5-HT2A receptor; altered states of consciousness; temporal processing; human study; working memory; psilocybin; sensorimotor synchronization; Human; Consciousness; Cognition; Synchronization; Time perception; Behavior; Working memory; Biological receptor
• ISSN: 0269-8811; 1461-7285
• DOI: 10.1177/0269881106065859

Hallucinogenic psilocybin is known to alter the subjective experience of time. However, there is no study that systematically investigated objective measures of time perception under psilocybin. Therefore, we studied dose-dependent effects of the serotonin (5-HT)2A/1A receptor agonist psilocybin (4-phosphoryloxy-N, N-dimethyltryptamine) on temporal processing, employing tasks of temporal reproduction, sensorimotor synchronization and tapping tempo. To control for cognitive and subjective changes, we assessed spatial working memory and conscious experience. Twelve healthy human volunteers were tested under placebo, medium (115μg/kg), and high (250μg/kg) dose conditions, in a double-blind experimental design. Psilocybin was found to significantly impair subjects’ ability to (1) reproduce interval durations longer than 2.5 sec, (2) to synchronize to inter-beat intervals longer than 2 sec and (3) caused subjects to be slower in their preferred tapping rate. These objective effects on timing performance were accompanied by working-memory deficits and subjective changes in conscious state, namely increased reports of ‘depersonalization’ and ‘derealization’ phenomena including disturbances in subjective ‘time sense.’ Our study is the first to systematically assess the impact of psilocybin on timing performance on standardized measures of temporal processing. Results indicate that the serotonin system is selectively involved in duration processing of intervals longer than 2 to 3 seconds and in the voluntary control of the speed of movement. We speculate that psilocybin’s selective disruption of longer intervals is likely to be a product of interactions with cognitive dimensions of temporal processing -presumably via 5-HT2A receptor stimulation.