Clinical Summary
Clinical Summary: Impact of Cannabis Use on Time to Psychiatric Rehospitalization in Young Adults With Bipolar and Psychotic Disorders: A Survival Analysis
Young adults hospitalized for bipolar or psychotic disorders often have concurrent cannabis use, and the period just after discharge is when relapse and rehospitalization can happen fast. This study helps clinicians identify whether cannabis use at admission marks a higher near-term rehospitalization risk and where postdischarge efforts should be concentrated.
Design
This historical cohort study
N
200 patients
Population
young adults with psychotic or bipolar disorders
Duration
Patients included in the study were followed up between January 1, 2017, and May 31, 2023.
Key Findings
- Excluding tobacco and alcohol use, 87 (44%) young adults had current drug use at the time of index hospitalization; cannabis was the first drug used currently, with a prevalence rate of 43%, and 67% of current cannabis users were daily users.
- In the Cox regression model analysis, 95 of 187 patients had a readmission to full-time hospitalization over the year following index hospitalization, with a median delay of 95 days (interquartile range 1–3: 15; 349) since the discharge.
- After adjustment for covariates, current cannabis use at the time of index hospitalization was not associated with an increased risk of readmission during the 12 months following discharge (hazard ratio [HR]=1.6; 95% CI, 1.0–2.5).
- Sensitivity analyses showed a higher early risk: current cannabis use was associated with readmission over the first 3 months following discharge (HR=1.9; 95% CI, 1.1–3.3), while the association was nonsignificant over the first 6 months (HR=1.3; 95% CI, 0.8–2.2).
- Independent risk factors for readmission were absent or conflicted family relationship (HR =2.2; 95% CI, 1.4–3.2) and psychiatric hospitalization history (HR =2.1; 95% CI, 1.4–3.2).
Clinical Bottom Line
Cannabis use in young adults with bipolar or psychotic disorders is a marker of higher early rehospitalization risk, especially within the first 3 months after discharge, even though it did not predict readmission across the full 12 months after adjustment. The highest-yield clinical window is the immediate postdischarge period.
Practice Implications
- Prioritize follow-up planning during the first month after discharge for current cannabis users, because the study found the strongest excess readmission risk early and a median time to readmission of 95 days.
- Routinely assess cannabis use at admission in young adults hospitalized for bipolar or psychotic disorders, as 43% were current users and 67% of current cannabis users were daily users.
- Look beyond cannabis alone when stratifying rehospitalization risk: absent or conflicted family relationship (HR =2.2; 95% CI, 1.4–3.2) and psychiatric hospitalization history (HR =2.1; 95% CI, 1.4–3.2) independently identified patients at higher risk.
- Strengthen addiction assessment and referral during inpatient care, because 37% presented with a SUD diagnosis while only 12% received specialized care for addiction.
