Electrodermal and vascular orienting response in schizophrenic patients: relationship to symptoms and medication.

Peripheral indicators of autonomic nervous system activity, including electrodermal activity and finger-pulse volume, were investigated in 100 schizophrenic inpatients. Healthy siblings of the patients and healthy subjects matched for age and gender served as control groups. Acoustic stimuli (70 dB) were presented and orienting response (OR) parameters were determined independently for the two response systems. The relationship of both OR measures to negative symptoms and medication was studied. The two OR measures were found to be not interrelated, i.e. most of the subjects were discordant with regard to presence or absence of their OR in the two different response systems. The electrodermal, but not the vascular OR, differed between patients and control groups. Among patients receiving medication with anticholinergic effects there were significantly more electrodermal nonresponders than among patients without such medication. There was no indication that electrodermal nonresponders show more negative symptoms or generally more severe psychopathology than electrodermal responders.