Bilateral electrodermal activity in depressive patients.

Integrated bilateral skin conductance response and reactive lateral eye movements were studied in 19 depressive patients and 14 normal subjects during visual and verbal tasks and tone habituation sequence. Distinct right-left differences between depressed and normal subjects in reactive lateral eye movements were revealed. Both endogenous and reactive depression patients were classified as 'left-movers'. Marked bilateral differences were observed in electrodermal activity (EDA) in patients during verbal and visual tasks. In endogenous depression EDA was higher on the left hand compared with the right under all the conditions studied (visual and verbal, and tone habituation sequence). In reactive depression EDA was higher on the left side during the verbal task and tone habituation sequence and on the right side in the visual task. Neither result in reactive depression group attained significance. The results are interpreted as a reflection of a different pathophysiology underlying reactive and endogenous depression.