Human EEG spectra before and during cannabis hallucinations

Area of Science:

• Neuroscience
• Psychopharmacology

Background:

• Delta-9-tetrahydrocannabinol (THC) is the primary psychoactive component of cannabis.
• Understanding THC's effects on brain activity and individual variability is crucial.

Purpose of the Study:

• To investigate the electroencephalogram (EEG) correlates of subjective experiences induced by THC.
• To examine EEG markers of individual disposition to THC-induced experiences.

Main Methods:

• Twelve healthy volunteers received an oral dose of 200 µg/kg THC.
• EEG data were collected during resting, attention, eye closure, visual hallucinations, and body image disturbances.
• Period analysis of EEG frequency spectra was performed before and after THC administration.

Main Results:

• Significant EEG spectral differences were observed between resting states and THC-induced visual hallucinations or body image disturbances.
• THC experiences were associated with slower alpha and increased theta frequencies, resembling drowsiness and some schizophrenia findings.
• Distinct EEG patterns emerged during visual hallucinations versus body image disturbances, suggesting different functional brain states.
• Individuals with a higher tendency for THC-induced experiences showed higher modal alpha frequencies in resting EEG compared to those with a low tendency.

Conclusions:

• THC significantly modulates EEG spectral characteristics, correlating with specific subjective experiences.
• EEG can differentiate between various THC-induced states and may reflect individual susceptibility to THC.
• Resting EEG alpha frequency may serve as a potential biomarker for individual differences in THC response.