Disease and mood states are important determinants of quality of life (QOL). Low QOL, due to mood states, can be expected especially in psychiatric disorders such as depression. However, patients with seizure disorders may be even more affected because of the combined burden of physical episodes, psychiatric comorbidities, and psychosocial factors (e.g., stigma). In this study, we compare the quality of life in seizure disorders and clinical depression. Based on our earlier findings, we hypothesize that epilepsy patients fare better than patients with psychogenic, nonepileptic seizures (PNES), and we speculate that QOL in PNES is also lower relative to clinical depression. We estimate the relationships between type of seizures (epilepsy vs PNES), depression, and QOL (SF-36) using multiple regression, and we compare the SF-36 scores of patients with epilepsy and PNES (n = 194) with the normative data for clinical depression using one-sample t tests. Our findings indicate that depression contributes to the poor QOL in both epilepsy and PNES, but the patients with PNES, even those without depression, have worse QOL compared with both the epilepsy patients and the depression norms. We conclude that evaluating and treating mood states is as important as treating PNES itself when caring for patients with PNES, and it might be the first step toward improving their QOL. (C) 2003 Elsevier Inc. All rights reserved.