Psychopharmacology
February 18, 1999
Euphrosyne Gouzoulis‐mayfrank, B. Thelen, Elmar Habermeyer et al.
145 citations
A double-blind study with 32 healthy volunteers compared the effects of the entactogen MDE (a drug similar to ecstasy), the hallucinogen psilocybin, the stimulant d-methamphetamine, and a placebo. MDE produced pleasant emotional experiences such as relaxation, peacefulness, contentment, and closeness to others, along with stimulant and mild hallucinogen-like effects. It caused the strongest endocrine and autonomic responses among the three drugs, including rises in cortisol, prolactin, blood pressure, heart rate, and a moderate increase in body temperature. The contrast between subjective relaxation and physical activation was unique to MDE. Results support entactogens as a distinct class between hallucinogens and stimulants.
Behavioural Pharmacology
November 1, 1998
Euphrosyne Gouzoulis‐mayfrank, Karsten Heekeren, B. Thelen et al.
79 citations
In 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.
Neuropsychobiology
January 1, 2002
Euphrosyne Gouzoulis‐mayfrank, B. Thelen, Stefanie Maier et al.
69 citations
Psilocybin, a serotonergic hallucinogen, and the ecstasy-like drug MDE both slowed reaction times in a spatial attention task, while methamphetamine did not. Psilocybin caused especially slow responses to invalid cues at short intervals and a failure to inhibit responses to valid cues at long intervals for right visual field targets. These patterns resemble bilateral attention disengagement and a lateralized impairment of inhibition of return seen in acute psychotic states. The study used a double-blind design with 8 healthy volunteers per group. Limitations include small sample size, and the authors call for larger studies with other hallucinogens to explore links between visuospatial attention dysfunction and psychosis.
Pharmacopsychiatry
July 1, 1998
Euphrosyne Gouzoulis‐mayfrank, Frank Schneider, J. Friedrich et al.
16 citations
Hallucinogenic drugs like psilocybin can help identify links between psychological conditions and brain changes seen in both drug-induced and naturally occurring acute psychotic states. This paper discusses methodological considerations for such studies, including subject selection, repeated measures, and control groups. Two example studies are described: one examined psychopathological changes, facial expression, and semantic priming during a psilocybin-induced state; the other compared semantic priming effects after psilocybin, MDE, and d-methamphetamine. Results confirmed time-dependent effects of psilocybin and showed that increased priming effects were restricted to the psilocybin group.