Cannabis use was common before first manic episodes in bipolar disorder

What the researchers found

This review examined the relationship between cannabis use and the onset of mania in bipolar disorder. Across the studies reviewed, lifetime cannabis use among bipolar patients was approximately 70%, with about 30% meeting criteria for cannabis abuse or dependence.

Cannabis use was associated with younger age at onset of first manic episode and with more frequent depressive and manic episodes, though the evidence was somewhat inconsistent. Cannabis consumption was also related to poorer overall outcomes and an increased risk of rapid cycling or mixed episodes.

An unexpected finding emerged regarding cognition: neurocognitive functioning appeared to be better in bipolar patients who used cannabis compared to those who did not, though this may reflect a selection effect where higher-functioning individuals are more likely to access and use cannabis.

Why it matters

Bipolar disorder affects approximately 1-2% of the population, and cannabis is the most commonly used drug among bipolar patients. Understanding whether cannabis triggers or accelerates manic episodes has direct implications for clinical management of bipolar disorder.

The numbers in context

Approximately 70% lifetime cannabis use in bipolar patients. About 30% comorbid cannabis abuse or dependence. Cannabis use was associated with earlier first mania onset and more frequent mood episodes.

How the study worked

Literature review searching Medline and PsychInfo databases for articles published between 1972 and December 2013 using keywords related to first manic episode, onset of mania, bipolar disorder, and cannabis.

What this study cannot tell us

Definitions of cannabis use and dependence varied across studies. No controlled studies directly tested whether cannabis causes mania. The temporal relationship between cannabis use and first manic episode was often unclear. Selection biases in clinical samples may affect prevalence estimates.

How to read the evidence

Narrative review of existing studies with consistent associations but no controlled trials to establish causation.

When this study was published

Published in 2014. The relationship between cannabis and bipolar disorder continues to be studied.

The bigger picture

The high rate of cannabis use among bipolar patients raises the question of whether cannabis is a trigger, a self-medication attempt, or both. The association with earlier onset and worse course, combined with the unresolved causal direction, makes this a critical area for longitudinal research.

Questions still open

• Does cannabis trigger mania in genetically vulnerable individuals, or do early bipolar symptoms drive cannabis use? Would cannabis abstinence reduce episode frequency in bipolar patients? Do THC and CBD have different effects on mood cycling?

Common questions

Read the original research

Cannabis use and first manic episode.

Journal of affective disorders, 165, 103-8

Citation

Bally, Nathalie; Zullino, Daniele; Aubry, Jean-Michel. (2014). Cannabis use and first manic episode.. Journal of affective disorders, 165, 103-8. https://doi.org/10.1016/j.jad.2014.04.038

Explore the wider topic

• LGBTQ+ and Cannabis: Higher Use Rates and Recovery
• Cannabis-Induced Psychosis: What It Is, Who's at Risk, and What to Do
• BetterHelp, Cerebral, and Online Therapy: Honest Review
• Quitting Weed with ADHD: Why It Is Harder and What Actually Helps
• Quitting Weed with Depression: What You Need to Know
• Quitting Weed with PTSD: A Practical Guide
• Self-Medicating with Weed: Why It Works Until It Doesn't
• Weed and OCD: Self-Medicating Intrusive Thoughts
• Weed and PTSD: What the Research Actually Shows
• Weed and Childhood Trauma: ACEs, Self-Medication, and the Path to Real Healing
• Weed and Suicidal Thoughts: What You Need to Know