Relationships of depression and anxiety symptoms with seizure frequency: Results from a multicenter follow-up study

Purpose: Depressive and anxiety disorders are frequent among people with epilepsies. There are, however, only few longitudinal studies, which examine the relationship between these comorbid psychiatric disorders and epilepsy-related variables. Thus, we investigated the interrelationships of depression and anxiety symptoms with seizure frequency across time.

Methods: Before admittance to an epilepsy center (T1) and six months after discharge (T2), patients (n=198) with mainly difficult-to-treat epilepsies completed the Hospital Anxiety and Depression Scale (HADS). Correlation and path analyses were conducted.

Results: Depression and anxiety symptoms (HADS) as well as seizure frequency significantly decreased from baseline to follow-up. Both at T1 and T2, seizure frequency was slightly, but significantly correlated with depression and anxiety levels (r_s=0.17-.32). Cross-lagged-analyses showed that baseline (T1) level of depression significantly predicted frequency of seizures at follow-up (T2). However, anxiety at T1 was not a significant predictor of seizure frequency at T2 and seizure frequency at T1 did not predict either depressive or anxiety symptoms at T2.

Conclusion: The present findings emphasize the importance of psychiatric comorbidities, especially depression, for seizure frequency and its progress in patients with difficult-to-treat epilepsies referred to a specialized epilepsy center. Thus, comorbid psychiatric disorders need specific consideration as part of a comprehensive diagnostic and therapeutic treatment approach.