Electrodermal activity and vulnerability to schizophrenia: a review.

Because electrodermal variables show consistency over time and situations, and evidence of genetic loading, it is of interest to examine such measures in adult schizophrenics and in children at risk for the disorder. Samples of adult schizophrenics are heterogeneous with regard to electrodermal activity. One group, the nonresponders, fails completely to respond to simple moderate intensity nonsignal stimuli. The other, the responders, does not differ from normals in frequency of response to nonsignal stimuli, but tends to show elevated tonic levels, and bilaterally asymmetrical and rapidly recovering responses. These two groups differ in other physiological and psychological measures, and in clinical picture. The responder pattern is predictive of poor outcome of acute schizophrenic episodes. A similar hyperactive pattern was found to differentiate children genetically at high or low risk for schizophrenia, and to predict psychiatric breakdown in the former group in Mednick and Schulsinger's original high risk study. The relationship to risk has been less evident in later studies, but similar, albeit weaker, tendencies have been reported. It is concluded that the nonresponding pattern may be secondary to a clinical picture of withdrawal and confusion, whereas the responder pattern may index vulnerability to schizophrenic episodes. On the psychological level, it is argued that this relationship is best conceptualized in attentional terms couched in information-processing language.