Risk of mood disorders after epilepsy diagnosis: A nationwide retrospective cohort study in South Korea

Objective: Epilepsy is a globally prevalent neurological condition associated with mood disorders such as depression and bipolar disorder. This study analyzed the prevalence of and hazard ratios for mood disorders, as well as risk factors, among patients with newly diagnosed epilepsy using a comprehensive South Korean national health database. Method: Health insurance and health examination data (2004-2013) were utilized in this retrospective cohort study. Patients newly diagnosed with epilepsy based on International Classification of Diseases-10th revision codes and without a mood disorder history were included. Mean follow-up duration was 3.6 years and 4.1 years for the epilepsy and control cohorts, respectively. Cox proportional hazards models adjusted for demographic and health variables were used to estimate the risk of developing mood disorders post-epilepsy diagnosis. Results: A total of 2210 patients with epilepsy and 22,100 matched controls without epilepsy were included. Those with epilepsy exhibited a 3-fold increased risk of developing mood disorders compared with controls (incidence rate ratio: 3.10 [95% confidence interval (CI): 2.75-3.49]). The risk was highest in the first two years post-diagnosis (adjusted hazard ratio: 3.42 [95% CI: 2.90-4.03]). A notable increase in risk was also observed 8-10 years post-diagnosis (adjusted hazard ratio: 3.07 [(95% CI: 1.14-8.22]), indicating a sustained long-term risk. Conclusions: Epilepsy significantly increases the risk of mood disorders, with the highest risk observed shortly after diagnosis. Continuous monitoring and tailored interventions are essential for managing patients’ mental health. Integrated care approaches are needed to treat epilepsy and associated mood disorders.