Skin conductance and schizophrenic symptomatology

Skin conductance is a psychophysiological parameter that reflects fundamental processes such as attention and arousal. The present study explored whether deviations in skin conductance activity are associated with severity of schizophrenic symptoms. For this purpose, Skin Conductance Responses (SCRs) to discrete stimuli (80 dB noises) and Skin Conductance Levels (SCLs) of 37 schizophrenic patients and 31 healthy volunteers were recorded. In accordance with previous studies, schizophrenic patients were found to be hyporesponsive compared to healthy controls. More specifically, almost half of the patients (46%) did not react with any SCR to the first 3 stimuli, whereas only 10% of the control group exhibited such a non-responding. Accordingly, the mean amplitude of the first 3 SCRs - as measured in u Siemens - was found to be significantly lower in patients compared to controls. As well, mean SCL was found to be (marginally) elevated in the patient group. This was especially the case for patients who did exhibit SCRs. In the patient group, a negative correlation was found between amplitude of SCRs and symptom severity. This association was mainly carried by a significant correlation between positive symptoms and reduced SCRs. The clinical relevance of these findings is discussed in detail.