The relationship between epilepsy and depression: an update.

Several population-based studies and clinical data suggest the presence of strict relationships between epilepsy and depression. The incidence of depressive symptoms in patients with epilepsy is significantly higher than in the general population or in patients with other neurological disorders or chronic diseases, as shown by the majority, albeit not all, findings. Even the rate of suicide is higher in epileptic patients than in the general population. Such observations suggest the existence of common neurobiological substrates involving hyperactivity of the hypothalamus-pituitary-adrenal axis, as well as disturbances of different neurotransmitter systems, particularly serotonin and norepinephrine. The aim of this paper is to review the current literature on the prevalence, clinical manifestations and etiology of depression in epilepsy, with a particular focus on the possible pathophysiological mechanisms shared by the two conditions. In spite of the large amount of data, several questions remain open and further studies are necessary to explore more thoroughly the complex and bidirectional relationships between epilepsy and depression.