Multimodal Correlates of Cannabis Use among U.S. Veterans with Bipolar Disorder: An Integrated Study of Clinical, Cognitive, and Functional Outcomes

Abstract

Objective: Cannabis use (CU) is common among persons with bipolar disorder (BD). Evidence suggests that CU is associated with poorer outcomes among persons with BD; however, these findings remain inconsistent. The present exploratory study aims to examine clinical, functional, and cognitive correlates of CU among persons with BD. Methods: U.S. veterans with BD type I who participated in a large-scale, nationwide study were categorized into four groups: current CU, past CU, past other drug use, and no drug use. Bivariate analyses, univariate analyses of covariance, and Levene’s Test for Equality of Variance were used to compare groups on clinical, cognitive, and functional measures. Results: Of 254 (84.6% male) veterans with BD type I included in the analyses, 13 (5.1%) had current CU, 37 (14.5%) past CU, 77 (30.3%) past other drug use, and 127 (50%) reported no drug use. BD with CU was associated with post-traumatic stress disorder (PTSD) and experiencing lifetime suicidal ideation. Notably, current CU was associated with higher working memory performance, compared to both past CU and no drug use. Likewise, current CU was associated with higher functional capacity, compared to past CU as well as no drug use. Conclusions: These findings contribute to the growing literature on the complex effects of cannabis on BD. As the commercialization and legalization of cannabis increases, further research in this area is warranted to quantify posed risks to this population, and thereby guide clinical decision-making.

Keywords:

• Bipolar disorder
• cannabis use
• veterans
• multimodal correlates

Acknowledgments

The authors acknowledge Alysia Maffucci and John Concato, from the VA Connecticut Clinical Epidemiology Research Center (CERC), for their instrumental role in making data VA CSP 572 Study available.

Disclosure statement

The authors have no conflicts to report. Dr. Ranganathan has received research grant support from Roche. Dr. Ranganathan has served as a consultant to Bioxcel Therapeutics in the past 3 years. The authors have no additional income to report.

Additional information

Funding

This study was supported by National Institute of Mental Health (NIMH) [grant no. 5R25MH071584].