Hair concentrations of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in cannabis consumers psychiatric patients
medRxiv April 16, 2022 Yann Barguil, Laura Chiaradia, Guy Southwell et al. preprint
Among young cannabis consumers, a brief psychotic disorder may signal either acute cannabis psychosis or the onset of schizophrenia, yet no clinical or paraclinical criteria reliably differentiate them. In a study of 256 New Caledonian cannabis users, delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD) concentrations in head hair were measured at initial psychiatric consultation and after a 6-month follow-up. A high hair THC level (>0.7 ng/mg) combined with a low CBD/THC ratio (<0.26) emerged as a potential marker for chronic psychosis. For acute cannabis psychosis, the CBD/THC ratio was higher (>0.43) than for other personality disorders (<0.32). The findings suggest CBD may protect against THC's harmful effects, and hair cannabinoid analysis could aid psychiatric diagnosis and early management.