Phd Student Division of Clinical Pharmacy, School of Pharmacy, The Hebrew University Jerusalem, Israel
Background: Medical cannabis use is rising for vast medical conditions. However, there are concerns that its use might increase the risk of psychiatric events. To date, no real-world study has investigated this possible association.
Objectives: This study assesses the association between exposure to medical cannabis and risk for psychiatric hospitalizations.
Methods: Data were acquired from the Israeli Ministry of Health databases: the Israeli Medical Cannabis Agency and the mental health department. The linked data was used to create a self-controlled case series model to investigate the association between medical cannabis and the incidence of psychiatric hospitalization. The study period included records from April 2018 to February 2022, including patients who were treated with medical cannabis and were hospitalized during the study period. Based on dispensing data, we calculated the period of cannabis exposure, starting from 01-Apr-2018 until the date of hospitalization, while adding 40 days of exposure after the last dispensing since the prescribed amount suffices for one month of treatment. The self-controlled period of no exposure was calculated similarly when no cannabis exposure was documented. A washout period was defined for 30 days after the exposure period.
Results: 688 eligible patients were identified with at least one medical cannabis dispensed history during the study period. The mean age of the hospitalized patients was characterized by young age (29.6), slightly more than 50% were males, and the leading medical cannabis indication was post-traumatic stress disorder. The relative rate ratio for psychiatric hospitalization among all patients prescribed medical cannabis was 9.16 (95%CI: 2.60 to 31.63), comparing exposed with unexposed periods. During the washout period of 30 days after treatment, the rate ratio was lower and not statistically significant (3.15, 95%CI: 0.01-31.04. Subgroup analyses demonstrated a similar rate ratio for patients receiving cannabis for pain (9.54, 95%CI: 1.08-97.39), while the rate ratio for post-traumatic stress disorder patients was 11.70 (95%CI: 1.92-60.22).
Conclusions: Medical cannabis exposure was associated with a substantially increased risk of psychiatric hospitalization. Medical cannabis should be further investigated to evaluate its associated risk of psychiatric hospitalization.
