The temporal stability of electrodermal variables over a one-year period in patients with recent-onset schizophrenia and in normal subjects.

Test-retest stability of electrodermal (EDA) variables indexing both general autonomic arousal (e.g., skin conductance level, number of nonspecific skin conductance responses) and attention to external stimuli (e.g., number of skin conductance orienting responses, electrodermal responder/nonresponder status) was assessed in 71 young, recent-onset schizophrenia patients and 36 demographically matched normal subjects. Significant stability over a 1-year period was found for both patients and normal subjects for most EDA variables and for responder/nonresponder status, with test-retest correlations generally being higher for normal subjects. The lower reliability for patients was not attributable to symptomatic fluctuations during the follow-up period and may reflect poorer arousal regulation among the patients. Among measures of responding to nontask stimuli, a simple count of the number of orienting responses occurring was more stable than was a traditional trials-to-habituation measure.