Abstract, originally published in Epilepsy Behav.
Purpose: Psychiatric comorbidity is common in epilepsy and has a considerable impact on patient quality of life (QoL). This study aimed to analyze the relationship between seizure frequency, irritability, and depression and describe how they mediate each other’s effect on QoL in epilepsy.
Methods: This is a cross-sectional study of consecutive adults seen at an outpatient epilepsy clinic of a tertiary hospital in Barcelona, Spain. All the patients were evaluated for psychiatric comorbidity and administered the State-Trait Anger Expression Inventory-2 (STAXI-2), the Hospital Anxiety and Depression Scale (HADS), and the Quality Of Life in Epilepsy Inventory-10 (QOLIE-10). Mediation analysis with multiple linear regression followed by the Sobel test was performed.
Results: We studied 157 patients. Seizure frequency (R = -0.193, P = .053), irritability (R = 0.216, P = .039), and depression (R = -0.598, P < .001) had all a negative effect on QoL. In the adjusted linear regression model, depression was the only independent predictor of impaired QoL (B = -2.453 [95% confidence interval (CI): -3.161, -1.744], P < .001). The Sobel test showed that depression exerted a significant mediating effect on seizure frequency (Z = -1.984; P = .047) and irritability (Z = -3.669; P < .001) in their influence on QoL.
Conclusion: Depression is an independent predictor of worse quality of life and significantly mediated the effects of irritability and poor seizure control on quality of life impairment in patients with epilepsy.