Blood Flow and Cerebral Laterality in the Mescaline Model of Psychosis

Abstract

The psychological, neuropsychological, and neurometabolic effects of the hallucinogenic agent mescaline were investigated in 12 normal male volunteers. Between 3 1/2 and 4 hours after drug intake, mescaline produced an acute psychotomimetic state, as measured by the BPRS and PDS-P. The APZ questionnaire revealed the specific effects of mescaline in the visual system. Neuropsychological effects were studied with a face/ non-face decision task with known right hemisphere advantage, in which mescaline induced a decrease in functioning of the right hemisphere. In functional brain imaging using SPECT, mescaline produced a "hyperfrontal" pattern with an emphasis on the right hemisphere, which was correlated with mescalineinduced psychotomimetic psychopathology. Our findings question the validity of the concept of hypofrontality as an explanation for acute psychotic symptomatology.