HUMAN EEG SPECTRA BEFORE AND DURING CANNABIS HALLUCINATIONS

Abstract

EEG correlates of subjective experiences induced by .DELTA.9-trans-tetrahydrocannabinol (THC) and EEG correlates of individual disposition to such experiences were investigated. Twelve normal volunteers took 200 .mu.g/kg THC orally. The subjects were asked to signal subjective experiences. The EEG was analyzed (period analysis) before and repeatedly after THC ingestion, during resting, attention, eye closure, visual hallucinations and body image disturbances. EEG frequency spectra differed significantly between resting and visual hallucinations and body image disturbances. The differences included slower .alpha. and more .theta. during THC experiences, reminiscent of initial drowsiness EEG, and of some results in schizophrenia. The differences between spectra during visual hallucinations and during body image disturbances indicate different functional brain states. Subjects with a high tendency to cannabinol-induced experiences exhibited resting spectra before and after THC with higher modal .alpha. frequencies (reminiscent of subjects with high neuroticism scores) than subjects with a low tendency.