The perils of recreational marijuana use: relationships with mental health among emergency department patients

Risk of depressive disorders associated with medical cannabis authorization: A propensity score matched cohort study

There is an increase in the medical use of cannabis. However, the safety of medical cannabis, particularly for mental health conditions, has not yet been clearly established. Thus, this study assessed the risk of emergency department (ED) visits and hospitalization for depressive disorders among medical cannabis users. We conducted a retrospective longitudinal cohort study of patients who received medical authorization to use cannabis from 2014 to 2019 in Ontario, matched (1:3 ratio) to population-based controls using propensity scores. Conditional Cox regressions were used to assess the association between cannabis authorization and the outcome. A total of 54,006 cannabis-authorized patients and 161,265 controls were analyzed. Approximately 39% were aged under 50 years, 54% were female, and 16% had a history of anxiety or mood disorders. The adjusted hazard ratio (aHR) for depressive disorders was 2.02 (95%CI: 1.83-2.22). The aHR was 2.23 (1.95-2.55) among subjects without prior mental health disorders. The interaction between sex (or age) and exposure was not significant. In conclusion, medical cannabis authorization was associated with an increased risk of depressive disorders. This finding highlights the need for a careful risk-benefit assessment when authorizing cannabis, particularly for patients who seek cannabis to treat a depressive condition.

When Cannabis Use Goes Wrong: Mental Health Side Effects of Cannabis Use That Present to Emergency Services

Cannabis use is a modifiable risk factor for the development and exacerbation of mental illness. The strongest evidence of risk is for the development of a psychotic disorder, associated with early and consistent use in youth and young adults. Cannabis-related mental health adverse events precipitating Emergency Department (ED) or Emergency Medical Services presentations can include anxiety, suicidal thoughts, psychotic or attenuated psychotic symptoms, and can account for 25-30% of cannabis-related ED visits. Up to 50% of patients with cannabis-related psychotic symptoms presenting to the ED requiring hospitalization will go on to develop schizophrenia. With the legalization of cannabis in various jurisdiction and the subsequent emerging focus of research in this area, our understanding of who (e.g., age groups and risk factors) are presenting with cannabis-related adverse mental health events in an emergency situation is starting to become clearer. However, for years we have heard in popular culture that cannabis use is less harmful or no more harmful than alcohol use; however, this does not appear to be the case for everyone. It is evident that these ED presentations should be considered another aspect of potentially harmful outcomes that need to be included in knowledge mobilization. In the absence of a clear understanding of the risk factors for mental health adverse events with cannabis use it can be instructive to examine what characteristics are seen with new presentations of mental illness both in emergency departments (ED) and early intervention services for mental illness. In this narrative review, we will discuss what is currently known about cannabis-related mental illness presentations to the ED, discussing risk variables and outcomes both prior to and after legalization, including our experiences following cannabis legalization in Canada. We will also discuss what is known about cannabis-related ED adverse events based on gender or biological sex. We also touch on the differences in magnitude between the impact of alcohol and cannabis on emergency mental health services to fairly present the differences in service demand with the understanding that these two recreational substances may impact different populations of individuals at risk for adverse events.