Effects of varied doses of psilocybin on time interval reproduction in human subjects

Neurosci Lett. 2008 Apr 11;435(1):51-5. doi: 10.1016/j.neulet.2008.02.006. Epub 2008 Feb 9.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / drug effects*
  • Brain / physiology
  • Cognition / drug effects*
  • Cognition / physiology
  • Consciousness Disorders / chemically induced
  • Dose-Response Relationship, Drug
  • Female
  • Hallucinogens / administration & dosage*
  • Humans
  • Judgment / drug effects*
  • Judgment / physiology
  • Male
  • Mental Processes / drug effects
  • Mental Processes / physiology
  • Psilocybin / administration & dosage*
  • Time Factors
  • Time Perception / drug effects*
  • Time Perception / physiology


  • Hallucinogens
  • Psilocybin