To explore the effects of depression on clinical outcomes in cognitively impaired patients with epilepsy. 

The robust association between dementia and epilepsy has been well demonstrated. The burden of depression in people with dementia and those with epilepsy is high. Preliminary studies suggest depression negatively affect disease outcomes in such population. Further investigation is needed to explore these relations to guide interventions for clinical outcome improvement.

This study used data from the United States National Alzheimer’s Coordinating Center (NACC) Uniform Data Set, conducted between September 2005 and September 2021. We included participants who had cognitive impairment (mild cognitive impairment or dementia) and were recorded as having seizures within the last year. Active depression was defined as depression within the last two years. Outcome assessment includes functional Assessment Questionnaire (FAQ) Score, Clinical Dementia Rating - Sum of Boxes (CDR-SB), Mini-Mental State Examination (MMSE) score and mortality. Logistic and linear regression analyses were used to assess the relationship between active depression and clinical outcomes. 

642 participants were diagnosed with both cognitive impairment and active seizures during the study period. 342 (53.3%) of them had active depression, and they were younger than participants without active depression (70.73±12.30 versus 73.34±11.51, p=0.01). Among our study population, the coexistence of active depression was associated with higher FAQ score (OR: 2.76, CI 1.29 - 5.89, p=0.01) and mortality (OR: 1.46, CI 1.07 - 1.99, p=0.02). Cognitively impaired patients with active seizures and depression had higher CDR-SB score (β= 0.68, CI -0.35 - 1.71, p=0.20) and lower MMSE score (β= -1.53, CI -3.50 - 0.45, p=0.13) than their counterpart without depression, but not statistically significant.

The comorbidity of depression in patients with cognitive impairment and epilepsy lead to worse functional status and higher mortality. It might also negatively impact cognitive outcomes. Effective screening and management of depression in these population is essential.