JAMA Psychiatry. Published online May 24, 2023.
Question: Is cannabis use disorder associated with an increased risk of psychotic and nonpsychotic unipolar depression and bipolar disorder?
Findings: In this cohort study of 6 651 765 individuals in Demark, cannabis use disorder was associated with an increased risk of both psychotic and nonpsychotic unipolar depression and bipolar disorder.
Meaning: The findings suggest that cannabis use disorder is independently associated with bipolar disorder and unipolar depression.
Importance: Cannabis use is increasing worldwide and is suspected to be associated with increased risk of psychiatric disorders; however, the association with affective disorders has been insufficiently studied.
Results: A total of 6 651 765 individuals (50.3% female) were followed up for 119 526 786 person-years. Cannabis use disorder was associated with an increased risk of unipolar depression (HR, 1.84; 95% CI, 1.78-1.90), psychotic unipolar depression (HR, 1.97; 95% CI, 1.73-2.25), and nonpsychotic unipolar depression (HR, 1.83; 95% CI, 1.77-1.89). Cannabis use was associated with an increased risk of bipolar disorder in men (HR, 2.96; 95% CI, 2.73-3.21) and women (HR, 2.54; 95% CI, 2.31-2.80), psychotic bipolar disorder (HR, 4.05; 95% CI, 3.52-4.65), and nonpsychotic bipolar disorder in men (HR, 2.96; 95% CI, 2.73-3.21) and women (HR, 2.60; 95% CI, 2.36-2.85). Cannabis use disorder was associated with higher risk for psychotic than nonpsychotic subtypes of bipolar disorder (relative HR, 1.48; 95% CI, 1.21-1.81) but not unipolar depression (relative HR, 1.08; 95% CI, 0.92-1.27).
Conclusions and Relevance: This population-based cohort study found that CUD was associated with an increased risk of psychotic and nonpsychotic bipolar disorder and unipolar depression. These findings may inform policies regarding the legal status and control of cannabis use.
(Source: https://jamanetwork.com/journals/jamapsychiatry/article-abstract/2804862 )