Cannabis Withdrawal and Psychiatric Intensive Care

Area of Science:

• Psychiatry
• Addiction Medicine
• Public Health

Background:

• Cannabis use is prevalent among individuals with severe mental illness.
• Cannabis withdrawal syndrome (CWS) can manifest with symptoms like agitation and irritability, typically peaking 3-5 days post-abstinence.
• Adverse outcomes in this population may be linked to CWS, not solely cannabis use itself.

Purpose of the Study:

• To investigate the association between pre-admission cannabis use and the risk of transfer to a psychiatric intensive care unit (PICU).
• To determine if this risk is elevated during the established cannabis withdrawal risk period (3-5 days post-admission).

Main Methods:

• Retrospective cohort study utilizing a secondary mental health care database from 4 London psychiatric hospitals (2008-2023).
• Included adult patients admitted to general psychiatric wards and PICUs.
• Cannabis use identified via clinical records using natural language processing and manual review. Outcomes analyzed using multivariable models adjusting for key demographic and clinical factors.

Main Results:

• Over 52,000 admissions were analyzed; 9.0% involved PICU admission.
• Cannabis users had a significantly higher likelihood of PICU admission (aOR, 1.44).
• Transfer to PICU between 3-5 days post-admission was more common in cannabis users (31.0% vs 24.2%, aOR, 1.36), particularly in women and individuals over 35 years old.

Conclusions:

• Cannabis use prior to psychiatric admission is associated with an increased risk of PICU transfer, especially during the CWS risk period.
• Cannabis withdrawal syndrome may exacerbate psychiatric conditions, leading to higher care needs.
• The findings highlight the importance of considering cannabis use and potential withdrawal in managing patients with severe mental illness.