Sex differences in bipolar disorder: Impact of lifetime cannabis use on clinical course, functioning, and quality of life in bipolar disorder.

BACKGROUND: Cannabis use is markedly prevalent among patients with bipolar disorder (BD). However, to date, there have been no studies on this issue with a sex-based approach. This study examines if lifetime cannabis use (LCU) is differently associated with clinical course, functioning, and quality of life (QoL) in patients with BD by sex. METHODS: Secondary analysis of a cross-sectional, naturalistic, multicentre study. LCU was defined as having had at least one day of use per month for at least 12 consecutive months in a patient's life. RESULTS: A total of 224 patients with BD were included (65.2% women). Patients with LCU were younger (p = 0.001) and had their first hospitalization earlier (p<0.005) than those without LCU, regardless of sex. Among women, LCU was associated with being single (p = 0.006), worse sexual functioning (p = 0.006), financial functioning (p = 0.009), QoL [bodily pain (p = 0.009), vitality (p = 0.027), social functioning (p = 0.037), emotional role (p = 0.038), mental health (p = 0.001), and mental summary component (p = 0.012)]. After controlling for confounders, among women, LCU was associated with worse QoL, specifically on bodily pain (p = 0.049) and mental health (p = 0.016) subscales. Among males, no statistically significant differences were found between LCU and no LCU (NLCU) in any of the variables of the study. LIMITATIONS: This study was a secondary analysis not powered specifically to analyze cannabis use. CONCLUSIONS: LCU was associated with a younger age at first hospitalization in both women and men, while only women reported worse QoL on bodily pain and mental health subscales. Clinicians and public health providers should be aware of this and inform their patients and the general population of these detrimental effects.