title: Effects of psilocybin on time perception and temporal control of behaviour in humans.
abstract: 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 (115 microg/kg), and high (250 microg/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.
authors.affiliation: Generation Research Programme, Human Science Centre, Ludwig-Maximilian University Munich, Bad Tölz, Germany, and Heffter Research Centre, University Hospital of Psychiatry, Zürich, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Wittmann
authors.forename: Olivia
authors.initials: O
authors.lastname: Carter
authors.forename: Felix
authors.initials: F
authors.lastname: Hasler
authors.forename: B Rael
authors.initials: BR
authors.lastname: Cahn
authors.forename: Ulrike
authors.initials: U
authors.lastname: Grimberg
authors.forename: Philipp
authors.initials: P
authors.lastname: Spring
authors.forename: Daniel
authors.initials: D
authors.lastname: Hell
authors.forename: Hans
authors.initials: H
authors.lastname: Flohr
authors.forename: Franz X
authors.initials: FX
authors.lastname: Vollenweider
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003861:Depersonalization / Q000139:chemically induced; D018491:Dopamine Agonists / Q000009:adverse effects / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006213:Hallucinogens / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects; D010507:Periodicity; D011562:Psilocybin / Q000009:adverse effects / Q000494:pharmacology*; D011597:Psychomotor Performance / Q000187:drug effects*; D012016:Reference Values; D058825:Serotonin 5-HT1 Receptor Agonists; D058826:Serotonin 5-HT2 Receptor Agonists; D013028:Space Perception / Q000187:drug effects; D013997:Time Factors; D013998:Time Perception / Q000187:drug effects*
chemical_list: D018491:Dopamine Agonists; D006213:Hallucinogens; D058825:Serotonin 5-HT1 Receptor Agonists; D058826:Serotonin 5-HT2 Receptor Agonists; D011562:Psilocybin