Interictal mood disorder and quality of life in active epilepsy

Although it is known that depressive symptoms have significant impact on quality of life (QOL) in epilepsy and that atypical symptoms are common in interictal depression, less is known about the clinical significance of the atypical form of interictal depression as opposed to major depressive disorder (MDD). We compared quality of life among 30 patients with epilepsy (1) with major depressive disorder (group D), (2) with interictal dysphoric disorder (group ID), and (3) without MDD or IDD (group ND). The mean t scores on the 31-item Quality of Life in Epilepsy questionnaire were lower in groups D (20.3, 95% CI 9.02-31.7, n=3) and ID (38.7, 95% CI 34.2-43.2, n=19) compared with group ND (59.1, 95% CI 52.2-66.1, n=8). These results underscore the clinical significance of IDD that not only accounts for a large portion of mood symptoms in the population with epilepsy, but also is not adequately captured by the DSM-IV criteria for MDD.