title: Effects of varied doses of psilocybin on time interval reproduction in human subjects.
abstract: Action of a hallucinogenic substance, psilocybin, on internal time representation was investigated in two double-blind, placebo-controlled studies: Experiment 1 with 12 subjects and graded doses, and Experiment 2 with 9 subjects and a very low dose. The task consisted in repeated reproductions of time intervals in the range from 1.5 to 5s. The effects were assessed by parameter kappa of the 'dual klepsydra' model of internal time representation, fitted to individual response data and intra-individually normalized with respect to initial values. The estimates kappa were in the same order of magnitude as in earlier studies. In both experiments, kappa was significantly increased by psilocybin at 90 min from the drug intake, indicating a higher loss rate of the internal duration representation. These findings are tentatively linked to qualitative alterations of subjective time in altered states of consciousness.
authors.affiliation: Department of Empirical and Analytical Psychophysics, Institute for Frontier Areas of Psychology and Mental Health, Wilhelmstrasse 3a, D-79098 Freiburg i. Br., Germany. jw@igpp.de
authors.forename: Jirí
authors.initials: J
authors.lastname: Wackermann
authors.forename: Marc
authors.initials: M
authors.lastname: Wittmann
authors.forename: Felix
authors.initials: F
authors.lastname: Hasler
authors.forename: Franz X
authors.initials: FX
authors.lastname: Vollenweider
mesh_terms: D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D003071:Cognition / Q000187:drug effects* / Q000502:physiology; D003244:Consciousness Disorders / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D005260:Female; D006213:Hallucinogens / Q000008:administration & dosage*; D006801:Humans; D007600:Judgment / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008606:Mental Processes / Q000187:drug effects / Q000502:physiology; D011562:Psilocybin / Q000008:administration & dosage*; D013997:Time Factors; D013998:Time Perception / Q000187:drug effects* / Q000502:physiology
chemical_list: D006213:Hallucinogens; D011562:Psilocybin