Depression in epilepsy: a frequently neglected multifaceted disorder.

Depressive disorders (DDs) are frequent psychiatric comorbidities of neurological disorders like multiple sclerosis, stroke, dementia, migraine, Parkinson's disease, and epilepsy. The clinical manifestations of DDs in these neurological disorders are identical to those of idiopathic mood disorders. In epilepsy, however, DDs can frequently also present with clinical characteristics that differ from those of idiopathic depression and fail to meet the criteria included in the Diagnostic and Statistical Manual of Psychiatric Disorders-Fourth Edition. Despite their multifaceted clinical expressions and their relatively high prevalence in epilepsy, DDs very often go unrecognized and untreated. The aim of this article is to review some of the more relevant aspects of DDs in epilepsy, to highlight their various clinical expressions, and their impact on the quality of life of patients with epilepsy, and to review the basic principles of treatment.