Cannabis-induced psychosis presenting to a psychiatric emergency department: a case series

Background The trend of legalizing medical cannabis is related to its increased illicit use worldwide. In Taiwan, cannabis has become the fifth most used illicit substance, with continuous increases in its use since 2018; yet, the potential risk of adverse mental health due to cannabis use has not been sufficiently emphasized.Methods In this study, we present the findings from a case series of six patients with cannabis-induced psychosis.Results Two of them had prior psychotic disorders in remission. Four patients showed violent behaviors, and other two showed lethal suicidal behaviors under the influence of cannabis. Two of the six patients were hospitalized for more than 2 weeks owing to the prolonged psychotic state.Conclusions Clinicians, patients with psychosis, and cannabis users in Eastern countries should pay more attention to the complex models of cannabis use and the public risk of related violent behaviors exhibited by patients under psychosis.