AUTONOMIC ABNORMALITIES IN SCHIZOPHRENIA - STATE OR TRAIT INDICATORS

Background: Tonic electrodermal measures have been widely used to inde x autonomic abnormalities : m schizophrenia, whereas phasic electroder mal nonresponsiveness has been frequently used to index attentional or ienting abnormalities. The primary objective of the present study was to assess whether these electrodermal abnormalities are episode indica tors or vulnerability indicators. Methods: Twenty patients with a rece nt first episode of schizophrenia were tested during symptomatically r emitted states and psychotic states. Twenty demographically matched no rmal controls were tested at two comparable intervals. Testing for sta bility of abnormalities across remitted and psychotic states allowed u s to determine whether tonic and phasic electrodermal measures qualify as episode indicators or vulnerability indicators. Results: Tonic ele ctrodermal activity was abnormally elevated only during the psychotic state, which indicates that it is an episode indicator in schizophreni a. Phasic hyporesponsiveness relative to levels of general activation was present in both the remitted and the psychotic states, most striki ngly during the psychotic state, and the proportion of patients who we re electrodermally nonresponsive tended to be abnormally high during t he remission test. Conclusion: Tonic electrodermal hyperarousal appear s to be a state-sensitive episode indicator, whereas phasic electroder mal hyporesponsiveness to innocuous stimuli relative to activation lev el appears to be a mediating vulnerability factor.