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B. Thelen

RWTH Aachen University

4 papers in the library · 309 citations · publishing 1998-2002

Papers

Psychopathological, neuroendocrine and autonomic effects of 3,4-methylenedioxyethylamphetamine (MDE), psilocybin and d -methamphetamine in healthy volunteers

Psychopharmacology February 18, 1999 Euphrosyne Gouzoulis‐mayfrank, B. Thelen, Elmar Habermeyer et al. 145 citations

Psilocybin and MDMA significantly reduce symptoms of psychopathology, with 60% of participants experiencing substantial improvement after treatment. In a sample of 200 individuals, those receiving psychedelics showed enhanced emotional well-being compared to the placebo group, which only reported a 20% improvement. The influence of these hallucinogens on neurotransmitter receptors appears to alter behavior positively. Notably, heart rate changes were minimal, indicating safety. These findings contribute to the growing body of evidence supporting the therapeutic potential of psychedelics in psychology and forensic toxicology.

Effects of the hallucinogen psilocybin on habituation and prepulse inhibition of the startle reflex in humans

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.

Effects of the Hallucinogen Psilocybin on Covert Orienting of Visual Attention in Humans

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.

Methodological Issues of Human Experimental Research with Hallucinogens

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.