Major depressive disorder in epilepsy clinics: A meta-analysis

Background and purpose: Although depression is a frequent psychiatric comorbidity in people with epilepsy (PWE), its prevalence has been underestimated. Comorbid depression has negative impacts on treatment outcomes and quality of life (QOL). It also causes various problems in PWE, such as fatigue, irritability, and suicidality. This meta-analysis was performed to estimate the frequency of major depression disorder (MDD) in clinics managing PWE.

Methods: We searched MEDLINE, EMBASE, Cochrane Library, Web of Science, and SCOPUS to identify studies. Hospital-based studies and original research presenting information regarding prevalence of MDD, determined using a gold standard diagnostic tool in adult PWE, were considered for inclusion. The prevalence of depression was examined by meta-analysis. In addition, subgroup analysis was performed based on the continent where the selected studies were conducted, the strictness of selection criteria, and gender. Strict selection criteria were defined as any mention of the use of exclusion criteria.

Results: A total of 6607 studies were identified by searching the five databases outlined above. After screening and rescreening, 35 studies were included in the meta-analysis. The total number of PWE was 5434. In the test for heterogeneity of the studies, I² was 68.014, and the Cochran Q value was 106.296 (p < 0.01). As a pooled estimate, the point prevalence of MDD in PWE was 21.9% with a 95% confidence interval (CI) of 20.8-23.0 in a fixed effects model. In subgroup analyses, continent partly explained the heterogeneity among the selected studies, but the strictness of selection criteria did not. The prevalence of MDD was higher in females than in males (26.4% vs. 16.7%, respectively) with an odds ratio (OR) of 1.805 (95% CI: 1.443-2.258; p < 0.01).

Conclusions: The point prevalence of MDD is estimated at 21.9% among PWE in epilepsy clinics and is higher in females than in males. Based on this relatively high prevalence in PWE, measures are required to identify and resolve MDD. In addition, the female predominance of MDD among PWE indicates a need to pay greater attention to females. Such efforts may reduce the impact of depression in PWE and improve their QOL.