Longitudinal trajectories of anxiety, depression, and bipolar disorder in inflammatory bowel disease: a population-based cohort study.

Background: Inflammatory bowel disease (IBD) is associated with psychiatric diseases, but it is unclear to what degree patients with IBD are affected over their lifetime. We aimed to longitudinally investigate the risk of anxiety, depression, and bipolar disorder before and after IBD diagnosis to understand the full burden of these diseases in patients with IBD.

Methods: In this population based cohort study, we identified 22,103 patients diagnosed with IBD between January 1, 2003 and December 31, 2013 in the Danish National registers and 110,515 matched reference individuals from the general population. We calculated yearly prevalence of hospital contacts for anxiety, depression, and bipolar disorder and dispensed prescriptions for antidepressants from five years before to ten years after IBD diagnosis. We used logistic regression to calculate prevalence odds ratios (OR) for each outcome prior to IBD diagnosis, and Cox regression to calculate hazard ratios (HR) of new outcomes after IBD diagnosis.

Findings: During >150,000 person years follow-up, patients with IBD had higher risk of anxiety (OR 1.4; 95% confidence interval (CI) 1.2-1.7) and depression (OR 1.4; 95% CI 1.3-1.6) starting at least five years before and continuing until at least ten years after IBD diagnosis (HR 1.3; 95% CI 1.1-1.5 for anxiety and HR 1.5; 95% CI 1.4-1.7 for depression). The risk was particularly high around IBD diagnosis and in patients diagnosed with IBD after the age of 40 years. We found no association between IBD and bipolar disorder.

Interpretation: This population-based study suggests that anxiety and depression are clinically significant comorbidities of IBD both before and after IBD diagnosis, which warrant thorough evaluation and management, particularly around the time of IBD diagnosis.

Funding: The Danish National Research Foundation [DNRF148], the Lundbeck Foundation [R313-2019-857], and Aage og Johanne Louis-Hansens Fond [9688-3374 TJS].