Abstract

Individual differences of activation, which determine levels of the responsiveness or excitation of individuals to the stimuli, can be considered personality characteristics reflecting the properties of nervous system. And activation level in man is presumed to vary diurnally in a circadian rhythm due to time variation and environmental influences. Present research aimed to investigate the characteristics of activation levels and it's diurnal rhythms in schizophrenics. For this purpose, two-dimensional activation of cortical arousal and autonomic activation in both trait and state was emphasized in this research. 9 chonic schizophrenics as the experimental group and 14 normals as the control group were asked to complete the Korean version Eysenck Personality Questionnaire(EPQ) and the short-form Activation-Deactivation Adjective Check List (AD-ACL). EPQ is a questionnaire which was devised so as to assess trait activation, and AD-ACL is also a instrument based upon self-report for assessing activation states. In this research diurnal variation of state activation depending on endogenous rhythm as well as semipermanent trait of activation was emphasized. Results were as follows : (a) schizophrenics were higher than normals on trait cortical arousal but lower than normals on state cortical arousal. (b) On a trait autonomic activation level, there were not significant differences between schizophrenics and normals but schizophrenics were higher than normals on a state autonomic activation level. (c) In diurnal rhythm of state cortical arousal, inverted U-shaped curve normals but flattened curve in schizophrenics were found. For these results, it would be concluded that schizophrenics with higher trait cortical arousal levels presented lower state cortical arousal levels than normals, and that this elevated state autonomic activation in schizophrenics. Moreover, these results suggested various possible modifications of Eysenck and Thayers' two-dimensional activation theory as following; a)In connection with Strelau's 'reactivity-activity' model, trait cortical arousal would be regarded as reactivity that is a temperamental trait, compared with state cortical arousal would be regarded as activity that is an energetic characteristic of behavior being regulated by reactivity. b)Trait autonomic activation would be regarded as an abnormal trait that is a characteristic factor in neurotics, while state autonomic activation would be regarded as an abnormal state that is a common factor shared by all abnormal groups.