The neurometabolic effects of the hallucinogen psilocybin (PSI; 0.2 mg/kg), the entactogen 3,4-methylenedioxyethylamphetamine (MDE; 2 mg/kg) and the stimulant d-methamphetamine (METH; 0.2-0.4 mg/kg) and the drugs' interactions with a prefrontal activation taskwere investigated in a double-blind, placebo-controlled human [F-18]fluorodeoxyglucoseFDG-positron emission tomographicPET study (each group: n ϭ 8 Experimental studies of cerebral blood flow and metabolism with psychoactive drugs in humans aim to explore the interaction of these drugs with human brain function. Recent studies with hallucinogenic, "mind-expanding" drugs in healthy subjects provided evidence in favor of an altered functional interhemispheric balance From the Department of Psychiatry and Psychotherapy (EG-M, BT, HS), University of Technology (RWTH), Aachen, Germany; Department of Nuclear Medicine (MS, OS, CA, UB), University of Technology (RWTH), Aachen, Germany; Department of Psychiatry (MS), University of Ulm, Ulm, Germany; Pharmaceutical Institute (K-AK), University of Tübingen, Tübingen, Germany; Psychiatric and Neurological Hospital Christophsbad (LH), Göppingen, Germany.Address correspondence to: E. Gouzoulis-Mayfrank, M.D., Department of Psychiatry and Psychotherapy, University of Technology (RWTH), Pauwelsstrasse 30, D-52074 Aachen, Germany.Received March 14, 1998, accepted July 20, 1998 566 E. Gouzoulis-Mayfrank et al. N EUROPSYCHOPHARMACOLOGY 1999 -VOL . 20 , NO . 6 with right hemispheric dominance and an increased activity in frontocortical regions after acute administration of mescaline, psilocybin, or ketamine (Hermle et al. 1992; Vollenweider et al. 1997a, b). The most profound increase in metabolism was found in the anterior cingulate (Vollenweider et al. 1997a(Vollenweider et al. , 1997b, which is linked to both emotional and attentional functions (Vogt et al. 1992;Devinsky et al. 1995;Murtha et al. 1996). These functions are, in turn, tightly connected to both the effects of hallucinogens and the symptoms of schizophrenic and schizophrenia-spectrum psychoses.Hallucinogenic drug-induced states can be used as models for acute endogenous psychotic states in psychiatric research (Hermle et al. 1992; Vollenweider et al. 1997a, b;Gouzoulis-Mayfrank et al. 1998). Within the framework of this model psychosis paradigm neurometabolic data from the above-mentioned studies can be interpreted in the sense that acute psychotic states with prominent positive symptoms are linked to increased activity in frontal neocortical, and limbic areas. This is in contrast to the majority of functional neuroimaging studies with schizophrenic patients, which demostrate hypofrontality both in resting states (Buchsbaum et al. 1982;Farkas et al. 1984;Wolkin et al. 1988;Siegel et al. 1993) and under cognitive tasks believed to employ frontal brain areas (Cohen et al. 1987;Weinberger et al. 1988;Buchsbaum et al. 1990;Andreasen et al. 1992). However, most of these studies were performed with chronically ill patients on various neuroleptic medications, a...
