Skin conductance responses in unmedicated recently admitted schizophrenic patients

Skin conductance responses to repeated identical stimuli (11 or 21 tones, 85dBA, 1000 Hz, 1-sec duration, sine wave, fast onset) were studied in unmedicated recently admitted RDC diagnosed patients (13 schizophrenic and five paranoid psychotic) and in age- and sex-matched controls. Subjects were classified as nonresponders, fast habituators, habituators, and nonhabituators. The distribution did not differ between patients and controls. There were no nonresponders among the patients and no evidence of bimodality. Schizophrenic patients had more skin conductance responses than controls and a more irregular response course. Analyses of heart rate responses excluded defensive responses, but no conclusions could be drawn as to whether startle or orienting responses had been elicited. The patients had psychophysiological signs of high arousal. They were in an early phase of their illness, with “positive” psychotic symptoms. The absence of nonresponding may be related to the type of patients studied and the characteristics of the stimuli used (high intensity, fast onset tones).