Effects of the hallucinogen psilocybin on habituation and prepulse inhibition of the startle reflex in humans
Euphrosyne Gouzoulis‐mayfrank, Karsten Heekeren, B. Thelen, Hiltrud Lindenblatt, K.‐a. Kovar, Henning Saß, M.a. Geyer
Behavioural Pharmacology November 1, 1998 DOI: 10.1097/00008877-199811000-00011 via OpenAlex
Summary
AI-generated from the abstractIn a small double-blind, placebo-controlled study with 12 healthy subjects, the hallucinogen psilocybin increased prepulse inhibition (PPI) of the startle reflex, contrary to findings from animal models where hallucinogens disrupt PPI. Psilocybin had no clear effect on habituation of the startle reflex. These preliminary results suggest that the effects of hallucinogens on sensorimotor gating may differ between humans and animals, possibly due to differences in dose regimens or experimental parameters. Further research is needed to understand the relationship between hallucinogen-induced states and naturally occurring psychoses.
Study at a glance
| Characteristics | Double-blind, placebo-controlled human study Peer reviewed |
|---|---|
| Sample size | 12 |
| Population | Healthy subjects |
| Intervention | Psilocybin |
| Topics | Psilocybin |
| Keywords | Prepulse inhibition Habituation Hallucinogen Moro reflex |
| Citations | 79 |
| Key finding | Psilocybin increased prepulse inhibition of the startle reflex in healthy human subjects, with no clear effect on habituation. |
Abstract
Schizophrenic patients exhibit deficits in indices of sensorimotor gating, such as habituation and prepulse inhibition (PPI) of the startle reflex. Hallucinogenic drug-induced states are putative models for the early and acute stages of schizophrenic and schizophrenia-spectrum disorders. Hallucinogenic drugs have been shown to disrupt PPI and/or retard habituation of the startle reflex in animal models of schizophrenia, consistent with the view of hallucinogen-induced states as 'model psychoses'. We evaluated the effects of the hallucinogen psilocybin on PPI and habituation of the startle reflex in a double-blind, placebo-controlled human study with 12 healthy subjects. In contrast to animal studies, in our small human sample, psilocybin increased PPI, while having no clear effect on habituation (n = 6). These findings must be considered preliminary because several factors, including dose regimens and experimental parameters, may influence the results of studies on startle plasticity. Further investigations both with psychotic patients in different stages of the disease and with human and animal models of schizophrenia are needed in order to explore the effects of hallucinogens on sensorimotor gating and the relationship between information processing in hallucinogenic drug-induced states and the naturally occurring psychoses.