Skin conductance nonresponding and nonhabituation in schizophrenic patients.

Bilateral skin conductance (SC) and heart rate (HR) were measured for 18 RDC diagnosed schizophrenic patients during rest and during presentation of identical tones. Computed tomography scans were evaluated. All but two patients were on neuroleptic medication. Six patients were nonresponders, seven habituated to the tones and five were nonhabituators. Nonresponders had lower SC level, fewer SC spontaneous fluctuations and higher HR level than the other subgroups. On neuropsychological tests the performance of the habituator group was closest to that of healthy subjects. Nonresponders did not differ in clinical symptoms, anamnestic data or in the prevalence of psychiatric morbidity in their families. Seventeen percent of the nonresponders had poor premorbidity adjustment vs 80% of the nonhabituators. Nonhabituators had higher ranks in the following symptoms: Presence of commenting voices, and inability to feel. They also tended to have wider third ventricles than the other two subgroups. The results support earlier findings in our laboratory suggesting nonhabituators as an important subgroup among schizophrenic patients.