Interictal Non-Psychotic Affective Disorders in Patients With Epilepsy: Clinical and Neurophysiological Correlates

Background: Epilepsy is commonly accompanied by psychiatric comorbidities that adversely affect clinical outcomes and quality of life. Interictal non-psychotic affective disorders remain underrecognized despite their clinical relevance and are associated with mood instability and anxiety-depressive symptoms, potentially linked to dysfunction of limbic brain networks. Objective: To evaluate the clinical spectrum of interictal non-psychotic affective disorders in patients with epilepsy and to examine their associations with electroencephalographic (EEG) findings, structural brain abnormalities on MRI, and clinical characteristics of epilepsy. Methods: This single-center cross-sectional observational study included 136 patients with epilepsy aged 18–65 years, diagnosed according to the ILAE 2017 classification. Psychiatric assessment was performed using structured interviews and standardized scales, including the Montgomery–Åsberg Depression Rating Scale (MADRS), Hamilton Depression Rating Scale (HDRS), and Minnesota Multiphasic Personality Inventory (MMPI). All patients underwent EEG using the international 10–20 system and brain MRI. Clinical variables, including seizure frequency, disease duration, and antiseizure therapy, were recorded. Statistical analysis included χ² tests, t-tests, and logistic regression. Results: Psychiatric disorders were identified in 56% of patients, with interictal affective disorders observed in 25%. The most frequent manifestations included emotional lability, dysphoria, anxiety-depressive symptoms, and asthenic depression. EEG analysis demonstrated a predominance of temporoparietal and frontotemporal epileptiform activity in affected patients. MRI findings included hippocampal sclerosis and cortical atrophy. Logistic regression identified frontotemporal epileptiform activity, hippocampal sclerosis, and female sex as independent predictors of affective disorders. Conclusions: Interictal non-psychotic affective disorders are common in epilepsy and are associated with specific neurophysiological and structural brain abnormalities. These findings highlight the importance of routine psychiatric screening and a multidisciplinary approach in epilepsy management.