People with bipolar disorder who used cannabis regularly showed decision-making and daily functioning comparable to healthy non-users, while cannabis impaired decision-making in healthy people.
Bipolar disorder researchers, psychiatric clinicians, patients with bipolar exploring cannabis
Bipolar cannabis users matched healthy non-users on decision-making tasks
What the researchers found
Among 87 participants, people with bipolar disorder who used cannabis regularly (4+ times/week) performed comparably to healthy non-users on decision-making and functional capacity measures. In contrast, healthy participants who used cannabis showed impaired decision-making. Non-using bipolar participants performed worst.
Why it matters
This counterintuitive finding suggests cannabis may have different cognitive effects depending on underlying brain conditions, potentially normalizing disrupted decision-making circuits in bipolar disorder.
The numbers in context
N=87. Four groups compared. Bipolar cannabis users matched healthy non-users on Iowa Gambling Task and UPSA-2 scores. Cannabis use defined as 4+ times per week.
How the study worked
Observational study comparing 87 participants across four groups (healthy cannabis users, healthy non-users, bipolar cannabis users, bipolar non-users) on the Iowa Gambling Task and UCSD Performance-based Skills Assessment.
What this study cannot tell us
Small observational sample cannot establish causation. Selection bias: bipolar patients who use cannabis regularly may differ in important ways from those who do not. Cross-sectional snapshot does not capture long-term trajectories.
How to read the evidence
Small observational study with important selection bias concerns. Intriguing but needs replication in larger, controlled studies.
When this study was published
2025 study with novel findings on cannabis-bipolar cognitive interactions.
The bigger picture
This challenges the assumption that cannabis uniformly impairs cognition. If cannabis normalizes decision-making in bipolar disorder while impairing it in healthy brains, this could reflect fundamentally different underlying neurochemistry.
Questions still open
- Does cannabis genuinely improve bipolar cognition, or are higher-functioning bipolar patients more likely to use cannabis? Could cannabinoid-based treatments be developed specifically for bipolar cognitive deficits?
Common questions
Can cannabis help with bipolar disorder symptoms?
Does cannabis affect everyone's cognition the same way?
Read the original research
Chronic cannabis use in people with bipolar disorder is associated with comparable decision-making and functional outcome to healthy participants.
Translational psychiatry, 15(1), 506
Citation
Miranda, Alannah; Roberts, Benjamin Z; Holloway, Breanna M; Peek, Elizabeth; Rosberg, Holden; Ayoub, Samantha M; Piomelli, Daniele; Jung, Kwang-Mook; Barnes, Samuel A; Rossi, Steven; Geyer, Mark A; Perry, William; Minassian, Arpi; Young, Jared W. (2025). Chronic cannabis use in people with bipolar disorder is associated with comparable decision-making and functional outcome to healthy participants.. Translational psychiatry, 15(1), 506. https://doi.org/10.1038/s41398-025-03718-4
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