Chronic cannabis use in people with bipolar disorder is associated with comparable decision-making and functional outcome to healthy participants.

Impaired decision-making is often seen in people with bipolar disorder (BD), even those undergoing treatment. Targeted therapeutics are therefore needed. People with BD report that cannabis use (CU) attenuates such cognitive and behavioral symptoms. We hypothesized that 1) people with BD who do not use cannabis would exhibit poor decision-making and functional capacity relative to healthy comparison (HC) participants and 2) CU in people with BD would be associated with decision-making and functional capacity comparable to that of HC participants who do not use cannabis. HC and BD participants that either reported regular (≥4x/weekly) CU or no-CU were recruited (n = 87). Participants were tested on decision-making and functional capacity using the Iowa Gambling Task and UCSD Performance-based skills assessment (UPSA-2), respectively. CU was associated with impaired decision-making in healthy participants while CU in participants with BD was associated with better decision-making than their non-using counterparts and equivalent to decision-making in non-CU HC participants. Additionally, CU in people with BD was associated with UPSA-2 scores comparable to non-CU HC participants. Studies are needed to determine whether cannabinoid-related treatments improve such decision-making and function in people with BD.