The elevated prevalence of substance misuse in bipolar disorder (BD) has been well documented [1], with evidence that rates of comorbid substance use disorders (SUDs) are among the highest in BD relative to the other major psychiatric disorders [2,3]. As in the general population, tobacco and alcohol represent the most widely abused substances in BD, with cannabis representing the most common illicit substance of abuse [2,4]. Rates of lifetime cannabis use have been reported in up to 64% of individuals with BD [5], and data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) [2] reveal a 12-month prevalence rate of 7.2% for cannabis use disorders (CUDs) among those with a lifetime BD diagnosis [6]. This figure represents a 6-fold increased risk for CUDs in BD compared to the general population estimate of 1.2%, and increased risk relative to the other major psychiatric disorders, with CUD comorbidity rates ranging from 2.9 – 5.7% [6,7]. Among those with a more recent history of bipolar disorder (i.e., 12-month diagnosis), CUD comorbidity has been reported to be even higher, with rates as high as 9.4% [7].
