A Community-Based Study of Transient Cannabis-Induced Psychosis in the Emergency Department

Authors

• CJ Whitford, Michigan State University College of Human Medicine Medical Student
• Casey O'Brien, Michigan State University College of Human Medicine Medical Student
• Reed Stevens, Michigan State University College of Human Medicine Medical Student
• Andi Nations, Michigan State University College of Human Medicine Medical Student
• Cassidy Bachman, Michigan State University College of Human Medicine Medical Student
• Nawal Bennet, Pulmonary and Acute Health Research Operations - Corewell Health West
• Brian Lewis, Emergency Medicine - Corewell Health West
• Jason Seamon, Orthopedic Surgery - Corewell Health West
• Jeffrey Jones, Emergency Medicine - Corewell Health West

Document Type

Conference Proceeding - Restricted Access

Publication Date

5-8-2026

Abstract

An association between cannabis and psychosis has been described in the medical literature since the 1930s. Since the legalization of cannabis in 2018, emergency departments (EDs) in Michigan have reported a notable rise in visits related to neuropsychiatric toxicity. The purpose of this study was to describe the incidence, clinical features, and disposition of transient cannabis-induced psychosis (CIP) in West Michigan.

We performed a retrospective cohort study at seven EDs across 13 Michigan counties, reviewing consecutive cases of acute cannabis toxicity (ICD-10 code F12) over 24 months. Sites included rural, university-affiliated, and children's hospitals. Demographics, clinical features, and outcomes were extracted from electronic records. CIP cases were identified using DSM-5 criteria and compared with those patients presenting with other forms of acute cannabis toxicity. Chi-squared and t-tests were used to compare groups on key variables.

Of 1,617 patients with cannabis toxicity, 630 (39.0%) presented with neuropsychiatric symptoms, and 186 (11.5%) met criteria for CIP. CIP presentations included delusions (43.5%), hallucinations (29.0%), severe anxiety (21.5%), suicidal or homicidal ideation (16.6%), paranoia (11.8%), and behavioral disturbances (8.1%). Symptoms typically lasted 2-4 hours; the mean ED stay was 4.8 hours. Sedation or restraint was required in 33.9%. One-third were admitted, transferred to psychiatric care, or jailed. Compared to 712 patients with other forms of cannabis toxicity, CIP patients were younger, more likely to be male, consumed edibles, and had higher rates of pre-existing mental health conditions and polysubstance use. Data abstraction demonstrated excellent interrater reliability (kappa = 0.87).

Transient CIP accounted for more than one in ten ED visits for cannabis toxicity and was frequently associated with severe agitation, need for sedation, and hospital or psychiatric disposition. Clinicians should systematically screen for cannabis use in high-risk patients and integrate brief intervention and follow-up to mitigate recurrent psychosis and downstream psychiatric morbidity.

Recommended Citation

Whitford CJ, O'Brien C, Stevens R, Nations A, Bachman C, Bennet N, Lewis B, Seamon J, Jones J. A community-based study of transient cannabis-induced psychosis in the emergency department. Presented at: Research Day Corewell Health West; 2026 May 8; Grand Rapids, MI.

Comments

2026 Research Day Corewell Health West, Grand Rapids, MI, May 8, 2026. Abstract 1881