Electrodermal procedures have consistently yielded two groups of schizophrenic patients--responders and nonresponders--on the basis of their electrodermal responsivity to auditory stimuli. The reliability of this finding has proved to be a cornerstone of autonomic research in schizophrenia. Previous investigators have reported that neuroleptic medications have little or no effect on electrodermal responsivity to mild tones. The current research found that patients receiving neuroleptics with high anticholinergic properties showed significantly less electrodermal responsivity compared with those receiving low anticholinergic neuroleptics. This was true for both loud and mild auditory stimuli.