Left-sided EEG focus and positive psychiatric family history are independent risk factors for affective disorders in temporal lobe epilepsy

Abstract

To identify independent risk factors for affective disorders in temporal lobe epilepsy. We studied 97 patients with temporal lobe epilepsy (TLE) exploring variables like age, gender, family history of epilepsy and psychiatric disorders, duration of epilepsy, control of seizures, presence of aura and initial precipitant insult, abuse of substances, neuroimaging and EEG features. Forty-one patients (42.3% of the total population) had affective disorders. A positive family history of psychiatric disorders (O.R.=3.8; p=0.003) and interictal EEG epileptiform discharges involving the left temporal lobe (O.R.=2.9; p=0.041) were significantly associated with an increased risk for an affective disorder. These associations remained significant after logistic regression, confirming the independent effects of the risk factors observed. Moreover, a binary logistic regression model obtained was able to correctly predict presence or absence of a life-time affective disorder in 71.1% of patients. This study points out that a positive family history of psychiatric disorders and interictal EEG epileptiform discharges involving the left temporal lobe are isolated risk factors for affective disorders in TLE. Our results suggest that biological factors are crucial for affective disorders development in TLE. Further studies are necessary to better specify the genetic and anatomical substracts involved and how they come together to generate affective disorders in those patients.