Impact of depressed mood on neuropsychological status in temporal lobe epilepsy

Objectives-Depression is a common psychiatric complication of temporal lobe epilepsy. This study examined the effect of depressed mood on neuropsychol ogical performance among patients with chronic temporal lobe epilepsy. Methods-Seventy consecutive surgery candidates for medication resistant com plex partial seizures of unilateral temporal lobe origin were assessed for psychiatric symptoms and underwent comprehensive neuropsychological assessm ent. Results-Standardised psychiatric interview disclosed that 34% of the patien t sample exhibited significant depression. Controlling for seizure frequenc y, patients with comorbid depression at the time of neuropsychological asse ssment exhibited significantly poorer performance on measures of intelligen ce, language, visuoperceptual ability, memory, and executive function. With in lateralised temporal lobe epilepsy groups, the adverse effects of depres sion on cognitive function were greater in patients with left temporal lobe compared with those with right temporal lobe epilepsy. In addition, depres sion seemed to be underrecognised and undertreated as none of the patients with epilepsy and comorbid depression were treated for their psychiatric co ndition at the time of admission for monitoring. Conclusions-Depression, a common psychiatric comorbidity among patients wit h chronic temporal lobe epilepsy, seems to be undertreated and to have adve rse effects on cognitive functioning.