The contribution of addictovigilance data to the French medical cannabis experimentation.

In France, cannabis is the most widely used illicit psychoactive substance. Recently, a new market for cannabidiol (CBD) products has emerged called "cannabis light" or "cannabis well-being". In parallel, the experimentation of medical cannabis began on March 26, 2021, for specific indications. Some clinical effects of cannabis have been put forward for medical purposes; however, these are counterbalanced by adverse events (AEs). Data from addictovigilance and international literature on the risks associated with non-medical cannabis use have helped establish exclusion criteria for patients at risk of complications when using medical cannabis (such as those with psychotic disorders, severe cardiovascular, renal, or liver conditions). This also enables the early identification of AEs. Cannabis-based medications are composed of cannabidiol (CBD) and/or delta-9-tetrahydrocannabinol (THC) in varying concentrations. We aimed to present the contribution of the addictovigilance data regarding cannabis-related reports to the ongoing French experimentation on cannabis used for medical purposes, to anticipate potential adverse drug reactions in the treated patients. Among the 3164 patients included in the French experimentation, 1186 of them presented at least one AE. Some of the AEs reported in addictovigilance surveys on non-medical cannabis and CBD were observed during the experimentation of medical cannabis such as cardiovascular AEs (myocardial infarction, strokes, transient ischemic attack), psychiatric AEs (suicidal idea and attempt, depression), worsening of epilepsy, cognitive and/or sedative disorders. Given the potential for pharmacodependence of cannabis medications, it seems important for clinicians to gather the addiction history of their patients (past or present), particularly the use of non-medical cannabis (illicit) and non-medical CBD, to prevent and early detect any risk of abuse. The generalization of the use of medical cannabis was adopted and defined in the 2024 Social Security Financing Act. These medications will be accessible to patients by medical prescription for defined indications. Addictovigilance as well as pharmacovigilance monitoring is crucial in this context of continuing to make medical cannabis available in France. Adverse effects of interest will need to be monitored in particular, including neurological disorders (epilepsy exacerbation, cognitive disorders), psychiatric disorders (substance use disorder, suicidal behaviour), and cardiovascular disorders as well as any unexpected AEs. Close addictovigilance monitoring contributes to increasing the awareness of professionals involved in the clinical management of patients treated with medical cannabis.