Cannabis Withdrawal May Trigger Psychiatric Crises 3-5 Days After Hospital Admission | Research

The takeaway

Cannabis users admitted to psychiatric wards were 36% more likely to be transferred to intensive psychiatric care during the 3-5 day window when withdrawal symptoms peak, with women and older adults most affected.

Mental health professionals, cannabis users with psychiatric conditions, and anyone interested in cannabis withdrawal effects.

36% higher odds of psychiatric intensive care transfer during withdrawal window

What the researchers found

Among 52,088 psychiatric admissions in London over 16 years, cannabis users were 44% more likely than non-users to require psychiatric intensive care overall. During the specific 3-5 day post-admission window when cannabis withdrawal peaks, transfers to intensive care were more common in cannabis users (31.0%) than non-users (24.2%). The association was strongest in women (2x the odds) and adults over 35 (2.5x the odds).

Why it matters

Cannabis withdrawal is often overlooked in psychiatric settings. This study provides evidence that forced abstinence during hospitalization may trigger a predictable worsening of psychiatric symptoms during the withdrawal peak window, potentially leading to unnecessary escalation of care.

The numbers in context

N = 52,088 admissions. PICU admission overall: 9.0%. Cannabis users vs non-users for PICU: aOR 1.44. Transfer at 3-5 days: 31.0% vs 24.2% (aOR 1.36). Women: aOR 2.03. Over 35: aOR 2.53.

How the study worked

Retrospective cohort study using electronic health records from four psychiatric hospitals in London (2008-2023). Cannabis use status was determined through natural language processing of clinical records combined with manual review. Multivariable models adjusted for age, gender, ethnicity, diagnosis, tobacco use, stimulant use, and comorbid substance use disorders.

What this study cannot tell us

Cannabis use was identified from clinical records, which may undercount actual users. The study cannot definitively prove that withdrawal caused the transfers rather than other factors associated with cannabis use. The London population may not be representative of all psychiatric settings.

How to read the evidence

Large retrospective cohort (52,088 admissions) over 16 years with robust statistical adjustment. The temporal specificity of the 3-5 day window strengthens the withdrawal hypothesis.

When this study was published

Published in 2025 in JAMA Psychiatry with data through 2023.

The bigger picture

If cannabis withdrawal is causing predictable psychiatric deterioration in the first week of admission, hospitals could potentially plan for it with targeted interventions during the withdrawal window rather than reactive transfers to intensive care.

Questions still open

Would managing cannabis withdrawal symptoms proactively during admission reduce PICU transfers? Why are women and older adults disproportionately affected?

Common questions

What are cannabis withdrawal symptoms?

Cannabis withdrawal can include agitation, irritability, aggression, insomnia, and anxiety, typically peaking 3-5 days after stopping use. These symptoms can be particularly disruptive in people who already have severe mental illness.

Why were women more affected?

The study found women had twice the odds of transfer during the withdrawal window but did not determine why. Possible explanations include hormonal differences in cannabinoid metabolism or different patterns of cannabis use.

Read the original research

Cannabis Withdrawal and Psychiatric Intensive Care.

JAMA psychiatry, 82(8), 838-843

View on PubMed ↗Publisher’s paper ↗

Citation

Malik, Aliyah; Shetty, Hitesh; Oliver, Dominic; Reilly, Thomas J; Di Forti, Marta; McGuire, Philip; Chesney, Edward. (2025). Cannabis Withdrawal and Psychiatric Intensive Care.. JAMA psychiatry, 82(8), 838-843. https://doi.org/10.1001/jamapsychiatry.2025.1216