Hair cannabinoids for distinguishing acute psychosis from chronic psychosis in cannabis users with brief psychotic disorder

To make an early differential diagnosis, in cannabis users with psychotic disorders, between disorders of the schizophrenic field and disorders induced by cannabis. Among young consumers of cannabis, a brief psychotic disorder (BPD) can be either the clinical manifestation of acute cannabis psychosis (ACP) or an announcement of schizophrenia's onset. The clinical presentation is of the same order, and only the evolution of disorders makes it possible to differentiate between these entities. To date, no clinical or even less paraclinical criteria have made it possible to differentiate syndromes whose prognoses and management are different (Hirschtritt M. Perm J 2021;25:20.179). Since 2010, we measured delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD) concentrations in head hair among New Caledonian patients, all cannabis consumers (n = 256) (Barguil Y. medRxiv 2022.04.13.22273751). We wanted to determine if these patients, cannabis users, suffering from different mental pathologies, present particular phenotypes of capillary cannabinoid concentrations (THC and CBD). At the time of initial psychiatric consultation, a sample of 3 cm proximal length of head hair was prepared for analysis. Capillary THC and CBD were then assayed by GC-MS (LOQ: 0.05 ng/mg) (Kintz P. Forensic Sci Int 1995;70:175–82). At the end of the 6 months medico-psychologic follow-up from the initial evaluation, four groups of cannabis users were identified according to the final psychiatric diagnosis: control, acute cannabis psychosis (ACP), chronic psychosis (CP), and other personality disorders (OPD) groups. Samples for which CBD and/or THC were not detected were considered in this study because these patients are known to be cannabis consumers (urine samples were positive for THC-COOH prior to hair sampling). A threshold value was arbitrarily set at 0.0024 ng/mg for the calculation of ratios. In this study, a “high” level of THC detected (> 0.70 ng/mg) associated with a low CBD/THC ratio (< 0.26) are two parameters that taken together could be good markers of CP development. For OPD and ACP, discriminating between the two types of disease development is more ambiguous. Indeed, values for THC and CBD found in hair overlap and cannot discriminate between these two groups, even though THC seems to be lower and CBD higher in the ACP group than in the OPD group. It is necessary to calculate the CBD/THC ratios for patients to discriminate ACP from OPD. The ratios were higher in the ACP group (> 0.43) than in the OPD group (< 0.32). In this study, the CP group was composed of people who possessed high levels of THC in their hair. This data may be correlated with the fact that patients with CP smoke more joints, or smoke more potent cannabis joints than people from other groups. Moreover, in the CP group, values obtained for CBD and for CBD/THC ratios were lower than in the control and the ACP groups. CBD may play a role in the protection against chronic or periodic mental disease development. This study highlights, once again, the protective role of CBD against the deleterious effects of THC. In association with clinical evaluation, this toxicological approach could be helpful for psychiatric diagnosis and would allow early management of BPD in cannabis consumers. Schizophrenia, for example, is a progressive disease, and a delay in therapeutic management compromises the chances of socio-professional reintegration. Close collaboration between psychiatrists, medical biologists, and analysts allows assistance with the therapeutic approach. It would be possible to make a first diagnosis just after the initial psychiatric evaluation.