Bipolar disorder (BIPD) is a chronic and disabling illness with frequent comorbid addictive disorders (ADD). Little is known about the prevalence and correlates of cannabis use disorders (CUD) in that population.

We sought to characterize clinical, sociodemographic, childhood trauma and psychological correlates associated with CUD in bipolar patients.

Our main hypothesis was that BIPD + CUD patients would be more impulsive and affectively unstable than those without.

Patients enrolled in a French national network underwent a thorough assessment including lifetime diagnoses using the SCID-IV questionnaire and measures of current symptomatology (Altman and MADRS), impulsivity (BIS-10), emotional instability (AIM and ALS), hostility (BDHI) and history of childhood trauma (CTQ). Univariate and multivariate analyses were used to identify specific associations between several correlates and CUD status.

Among the 718 patients included, 414 (57.7%) were women, with a mean age of 43 years, and 546 (76.4%) were diagnosed with type I bipolar disorder and 190 (26.9%) had at least one lifetime substance use disorder. CUD were associated with lifetime history of suicidal behavior, psychotic symptoms during an affective episode, rapid cycling and CTQ sub-scores, clinical and psychological dimensions. Parts of these associations remained after controlling for comorbid alcohol use disorders.

These results suggest a high prevalence of CUD in BIPD, which was associated with a higher severity and worse outcomes of illness. Although the retrospective nature of this study prevents causal interpretations, our results suggest that at-risk traits among CUD+BIPD patients may induce these clinical features.