Comparing the Impact of Tetrahydrocannabinol on 30-Day Readmission Rates and Hospital Length of Stay in Patients With...

Delta-9-tetrahydrocannabinol (THC), the psychoactive constituent of cannabis, continues to be critically evaluated for its potential therapeutic efficacy and associated safety concerns in major depressive disorder (MDD). Length of stay and readmission rates are key indicators of treatment response and prognosis. With rising cannabis use, understanding the effects of THC is essential. The objective of this study is to evaluate THC's impact on 30-day readmission and length of stay among inpatient MDD individuals at an academic hospital.

A single-center retrospective chart review evaluated adult patients admitted for MDD between August 2018 and May 2025. Patients were categorized by positive or negative THC urine drug screen on admission. The primary outcomes were 30-day psychiatric readmission and hospital length of stay. Unadjusted and adjusted analyses were performed. Logistic regression was used to evaluate 30-day readmission, and multiple linear regression was used to evaluate length of stay. Adjusted models included age, gender at birth, psychiatric comorbidities, and polysubstance use.

Among 743 cases, 211 (28.4%) were THC positive. A THC-positive urine drug screen was not independently associated with 30-day psychiatric readmission (adjusted odds ratio [OR]: 0.821; 95% CI 0.319-2.115; p = 0.683) or difference in hospital length of stay (mean difference -0.242 days; 95% CI -0.983 to 0.499; p = 0.521). Older age was associated with longer length of stay, while female gender at birth was associated with shorter length of stay.

THC-positive urine drug screens were not independently associated with 30-day psychiatric readmission or differences in hospital length of stay among patients hospitalized for MDD. Larger studies are needed to further evaluate the relationship between cannabis use and psychiatric hospitalization outcomes.