Autonomic nervous system activity in acute schizophrenia: I. method and comparison with normal controls.

Many reports of autonomic dysfunction in schizophrenia may have been influenced by the chronicity or medication status of patients, or both. This study eliminates these sources of variation. Skin conductance (SC) and heart rate (HR) base levels and activity were compared in 118 controls and 46 recently admitted, drug-free, acute schizophrenic patients during rest, 20 mild-tone stimuli, and reaction time (RT) and mental arithmetic tasks. Patients showed higher than normal HR and spontaneous SC responses but lower SC base levels. Schizophrenics showed less SC and HR reactivity to tones and RT stimuli, slow habituation of the SC orienting response, an attenuated tonic response to stress, and disproportionately more spontaneous than elicited SC activity. The findings are similar to previous results for unmedicated, chronic schizophrenics and suggest that autonomic activity in schizophrenics is determined relatively more by endogenous factors than by external stimuli.