Impact of Cannabis Use Disorder on the Course and the Prognosis of Bipolar Disorder Type 1

Abstract: Objectives Bipolar Disorder (BD) is a psychiatric pathology marked by a significant socio-professional impact. Its comorbidity with other disorders would make the prognosis more severe. Addictive co-morbidities, particularly the Cannabis Use Disorder (CUD), are of great interest. The objective of our study was to determine the impact of cannabis use disorder on the course and prognosis of type 1 Bipolar Disorder (BD1). Methods: This is a cross-sectional and comparative study carried out on 75 patients with Bipolar Disorder type 1 (BD1) including 30 with a comorbid Cannabis Use Disorder (CUD+ group) without any other substance use disorder, compared to 45 without cannabis or any other substance use disorder (CUD- group). The CUD was evaluated according to the DSM-V criteria. The euthymia was verified by the Hamilton depression and Young mania scales. Compliance was assessed by the Medication Adherence Rating Scale questionnaire, insight by the Q8 scale and functioning by the Global Functional Assessment scale. Results: In our population of patients with BD1, CUD was associated with celibacy (p=0.021), residence in an urban area (p=0.013), professional instability (p=0.001) and a family dynamic marked by violence (p=0.04). CUD was also associated with tobacco use disorder (p=0.042), occasional alcohol consumption (p=0.001), personality disorders (p=0.003) especially the antisocial type (p=0.008), a history of stay abroad (p=0.008) and a criminal record (p = 0.016). Clinically and therapeutically, CUD was associated with more frequent manic relapses (p <0.001), poor insight (p<0.001), poor adherence to therapy (p=0.001), and prescription of antipsychotics long-acting (p=0.007) and benzodiazepines (p=0.036). The prognostic factors associated with CUD in a multivariate study and after adjusting for confounding variables were more frequent manic relapses (p<0.001; ORa=18; 95% CI 3.9-88), sub syndromic symptoms (p=0.007; ORa=3.7; 95% CI 1.4-9.8), more frequent hospitalizations (p<0.001; ORa=36; 95% CI 4.3-310) and more prolonged (p <0.001; ORa = 5; 95% CI 1.6- 5.5), lack of socio-professional reintegration (p=0.001; ORa=5.3; 95% CI 1.5-14.6) and overall poor functioning (p=0.001; ORa=6,8; 95% CI 2-22.6). Conclusion: Our study highlighted the deleterious impact of cannabis use disorder on the course and prognosis of bipolar disorder. Common in Tunisia and around the world, cannabis use disorder is a real scourge with negative consequences, especially on mental health. As a result, developing strategies for managing these comorbidities and developing international consensuses could constitute targets for curative actions and could have a positive impact on mental health.