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

Khedr M.; Lee Y.; Mirza M.; Jimenez H.; Greer D. · Brain and behavior · 2026

**Background & Methods** This single-center retrospective chart review analyzed 743 adult patients admitted for major depressive disorder (MDD) between August 2018 and May 2025 at an academic hospital. Patients were stratified by THC urine drug screen status on admission, with primary outcomes of 30-day psychiatric readmission and hospital length of stay assessed using logistic and multiple linear regression models adjusted for age, gender, psychiatric comorbidities, and polysubstance use. **Key Findings** • THC-positive urine drug screen was not independently associated with 30-day psychiatric readmission (adjusted OR: 0.821; 95% CI 0.319-2.115; p = 0.683) among the 211 THC-positive patients (28.4% of cohort). • THC positivity showed no significant difference in hospital length of stay compared to THC-negative patients (mean difference -0.242 days; 95% CI -0.983 to 0.499; p = 0.521). • Older age was independently associated with longer hospitalization, while female gender at birth was associated with shorter length of stay; polysubstance use and psychiatric comorbidities were not statistically significant in adjusted models. **Dosage & Administration** Not reported. The study used urine drug screening to detect THC presence but did not characterize dosage, frequency, route of administration, or timing of use. **Safety & Adverse Effects** Not reported. The study did not evaluate specific adverse effects or safety outcomes associated with THC use during hospitalization. Safety assessment was limited to readmission and length-of-stay metrics as proxy measures of clinical stability. **Evidence Quality** This retrospective chart review represents relatively low-level evidence (Level 4). Key limitations include: single-center design reducing generalizability; inability to establish causation from observational data; lack of characterization regarding THC dose, frequency, and timing; potential unmeasured confounding variables; and absence of standardized depression severity assessments or treatment protocols. The study's negative finding (no association between THC and outcomes) should be interpreted cautiously, as underpowered analyses or inadequate adjustment for confounders may explain null results. Authors appropriately acknowledge the need for larger prospective studies to clarify cannabis use's relationship with psychiatric hospitalization outcomes.

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