[Significance of historical and current hallucinogenic research in psychiatry]. / Zur Bedeutung der historischen und aktuellen Halluzinogenforschung in der Psychiatrie.

Research in experimental psychosis has a long tradition extending through several stages. With the world wide abuse of psychoactive substances it came to an abrupt end. Systematic questions within this framework of research are still unresolved, and research on newly developed compounds is almost completely lacking. A review of the pharmacological and psychological effects of various psychoactive agents is provided, and results of recent experimental studies on arylalkylamines are discussed. It is argued that from a systematic as well as from a methodological viewpoint the traditional approach of experimental psychosis represents a valuable tool in psychiatric research.

Mescaline-induced psychopathological, neuropsychological, and neurometabolic effects in normal subjects: experimental psychosis as a tool for psychiatric research.

The psychological, neuropsychological, and neurometabolic effects of the hallucinogenic agent mescaline were investigated in 12 normal men who were volunteers. Mescaline produced an acute psychotic state 3 1/2-4 hr after drug intake, as measured by the Brief Psychiatric Rating Scale (BPRS) and Paranoid Depression Scale (PDS). The Assessment of Altered States of Consciousness (APZ) questionnaire revealed specific effects of mescaline in the visual system. Neuropsychological effects were studied with a face/nonface decision task with known right-hemisphere advantage, in which mescaline induced a decrease of functioning of the right hemisphere. In functional brain imaging using single photon emission computed tomography (SPECT), mescaline produced a "hyperfrontal" pattern with an emphasis on the right hemisphere, which was correlated with mescaline-induced psychotic psychopathology. Our findings question the validity of the concept of hypofrontality as an explanation for schizophrenic symptomatology. The study of psychoactive substances under controlled laboratory conditions has the methodological advantage of intraindividual control, and hence, minimal variability of data.

Schizophrenia--an emotional hypersensitivity of the right cerebral hemisphere.

While modern neuropsychological and electrophysiological studies claim a functional disturbance of the left hemisphere (LH) in schizophrenia, historical clinical and anatomical work rather points to the right hemisphere (RH) as the main site of psychosis. In the light of an interhemispheric functional balance of inhibition and release, LH-dysfunction in schizophrenia could be interpreted as a consequence of an overactive and inhibiting RH. Since the RH is especially activated by emotional stimuli, and exaggerated distractability and sensitivity to emotional stimuli are hallmarks of schizophrenia, we compared the emotional irritability of the RH and LH in 35 acute schizophrenics and 22 matched controls. Using tachistoscopic half-field presentation we found in acute schizophrenics a selective impairment of RH-function with simultaneous improvement of LH-performance induced by emotional distractors. We therefore suggest that a right hemispheric dysfunction and hypersensitivity to emotional material plays an essential catalytic role in acute schizophrenia.