JPBS

Marijuana is the most widely consumed recreational drug in the world. In Canada, physicians are experiencing increasing pressure to prescribe medical marijuana, with proposed legalization coming in late 2018. The use of marijuana in the psychiatric population is increasing, and the prescribing process is largely unregulated. In spite of several medicinal indications, chronic marijuana use is associated with serious consequences including early-onset psychosis, addiction, persistent psychosocial dysfunction, and neuropsychological abnormalities. In this paper, we present the first spectral electroencephalography (EEG) study of brain changes during cannabis-induced psychosis coupled with a comprehensive review of the literature on medicinal and recreational marijuana use. The findings suggest that psychotic symptoms following cannabis are distinct from schizophrenic and affective psychoses, and occur as the consequence of a generalized shift to right hemispheric dominance. This is coupled with abnormal activation sources in the excitatory beta and gamma bands in the left temporo-parietal region, with impaired engagement of the relevant networks in both cognitive and spatial goal-directed tasks. Detailed recommendations for public education and prescribing process of medicinal marijuana use are discussed.

Jacques-Joseph Moreau de Tours, author of “Du hachisch et de l’aliénation mentale: études psychologiques,” 1845