Cannabis use among patients presenting to the emergency department for psychosis: Associations with restraint use, medication administration, psychiatric hospitalization, and repeat visits

Psychiatry Res. 2023 May:323:115151. doi: 10.1016/j.psychres.2023.115151. Epub 2023 Mar 20.


Cannabis use is associated with increased severity of psychotic symptoms and the risk of acute agitation and aggressive behavior in inpatient (IP) and outpatient settings. Whether or not cannabis use is associated with increased acuity of psychosis-related ED presentations and risk of repeat ED visits for psychosis is unclear. In this retrospective study of 2,134 ED visits for acute psychosis, we investigated the risk of physical restraint, parenteral medication administration, psychiatric hospitalization, and recurrent ED visits. We examined ED visits between March 1, 2019 and February 28, 2021 based on urinary Tetrahydrocannabinol (THC) screen status (positive vs negative vs no screen). The risk of physical restraint, parenteral antipsychotic, and benzodiazepine administration was significantly greater in ED visits with a positive THC screen compared to those with a negative or no THC screen. We did not find an association between a positive urinary THC screen and IP hospitalization or the risk of recurrent ED presentation for psychosis within 90 days. These findings suggest that positive urinary THC may predict acute agitation or acuity of symptoms in ED settings and underscores the importance of screening for THC during ED presentations for psychosis.

Keywords: Antipsychotic; Cannabis; Emergency department; Psychosis; Restraint; Schizophrenia.

MeSH terms

  • Cannabis*
  • Emergency Service, Hospital
  • Hallucinogens* / adverse effects
  • Hospitalization
  • Humans
  • Psychotic Disorders* / drug therapy
  • Psychotic Disorders* / psychology
  • Restraint, Physical
  • Retrospective Studies


  • Hallucinogens