• Article

Cannabis and bipolar disorder Does quitting cannabis use during manic/mixed episode improve clinical/functional outcomes?

Objective
To examine whether bipolar disorder patients who stop cannabis use during a manic/mixed episode have better clinical and functional outcomes than continued use or never use.

Method
Data from the European Mania in Bipolar Longitudinal Evaluation of Medication (EMBLEM), a 2-year prospective observational study in adults with a manic/mixed episode of bipolar disorder, was used. Three cannabis use groups were: current use (between 12-week and 24-month visits); no current but previous use (during first 12 weeks); and never use. Associations between cannabis use and outcomes were analyzed using regression models.

Results
Of 1922 patients analyzed, 6.9% were current users, 4.6% previous users, and 88.5% never users. Clinical outcomes differed between groups (P < 0.019): previous users had highest rates of remission (68.1%) and recovery (38.7%), and lowest rates of recurrence (42.1%) and relapse (29.8%). Logistic regression showed previous users had similar outcomes to never users (all P > 0.05), whereas current users had lower recovery (P = 0.004) and remission (P = 0.014), higher recurrence (P = 0.014), greater work impairment (P = 0.016), and were more likely not to be living with partner (P = 0.006) than never users.

Conclusion
Bipolar patients who stop using cannabis during manic/mixed episode have similar clinical and functional outcomes to never users, while continued use is associated with higher risk of recurrence and poorer functioning.

Citation

Zorrilla, I., Aguado, J., Haro, JM., Barbeito, S., Lopez Zurbano, S., Ortiz, A., ... Gonzalez-Pinto, A. (2015). Cannabis and bipolar disorder: Does quitting cannabis use during manic/mixed episode improve clinical/functional outcomes? Acta Psychiatrica Scandinavica, 131(2), 100-110. DOI: 10.1111/acps.12366

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