The skin conductance orienting response in neuroleptic-free schizophrenics: replication of the scoring criteria effect.

It has been suggested that the use of invalid scoring criteria might be responsible for the finding of excessive nonhabituation of the skin conductance orienting response (SCOR) in schizophrenia. Certain criteria may confuse SCOR and spontaneous SC activity in subjects with high rates of the latter (Levinson et al. 1984). To replicate this finding, data were reanalyzed from a study of 25 neuroleptic-free schizophrenic patients and 23 normal male subjects. Analysis of response latency and amplitude during a habituation paradigm of 11 78.5-dB tones confirmed the predictions. Broad scoring criteria (SCOR onset 1-5 sec poststimulus, and a three-no-response-trials habituation criterion) produced significantly different habituation scores than more restrictive criteria (1.6-3.0 sec latency window and a two-trials habituation criterion). Nonhabituation was scored in five patients and six normals by the former criteria, but in no patient and one normal by the latter. Nonhabituators, defined by using the broad criteria, had higher rates of spontaneous activity. The narrow latency window contained significantly more responses than could be explained by the spontaneous activity rate, but this was not true for the added time permitted by the broad window. It is concluded that the use of more restrictive scoring criteria may help to clarify the validity of SCOR nonresponse or hyporesponse as a marker for a type of schizophrenic illness.