A protocol for a pooled analysis of cohort studies: The association between depression and anxiety in epileptic disorders

Background/Introduction: Depressive and anxiety disorders constitute major mental health challenges affecting adults of all ages globally. It has been reported that individuals with depressive or anxiety disorders face an elevated risk of developing neurological conditions, including seizures and epilepsy. Additionally, people with these disorders tend to exhibit distinct clinical outcomes compared to the general population. However, the associations between depressive or anxiety disorders and epilepsy remain contentious. Thus, this study aims to elucidate the associations between these neuropsychiatric disorders, including depressive and anxiety disorders, and epilepsy or seizures. Methods: We will systematically search three electronic databases—PubMed, EMBASE, and the Cochrane Library—from inception through March 2023 to identify relevant cohort studies investigating the associations between depressive or anxiety disorders and epilepsy or seizures. Two independent reviewers will extract data from eligible studies using pre-designed standardized data extraction forms, and cross-check results. A third author will resolve any discrepancies. Quality assessment will be performed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Pooled risk estimates (Relative risks or hazard ratios with their 95% CI) will be calculated using the DerSimonian-Laird random-effects model. If between-study heterogeneity is identified, we will conduct subgroup analyses or meta-regressions to explore the possible sources of heterogeneity (participants, exposure, outcome, and study design) stratified by various study characteristics. Potential publication bias will be detected through the inspection of funnel plot asymmetry, complemented by the Egger linear regression approach (Egger’s test) and the Begg rank correlation test (Begg’s test). Discussion: This pooled analysis will evaluate the association between depressive or anxiety disorders and epilepsy or seizures, providing high-level evidence to inform early identification and prevention strategies for epilepsy or seizures. Ethics and dissemination: Given that the data utilized for analysis in this pooled analysis does not involve human subjects or medical records, no ethical approval is required for this study. We intend to present the results of this study at national or international conferences or submit the findings to a peer-reviewed journal. OSF registration number: DOI 10.17605/OSF.IO/WM2X8