Assessment of the premorbid personality in endogenous psychoses. A factor-analytical study of the adjective check list of von Zerssen (author's transl)

Abstract

In order to get information about the premorbid personality of patients with endogenous psychosis, we examined the adjective check list of von Zerssen with regard to form and content on a sample of 126 schizophrenic and 31 affective-psychotic patients. The data gathering occured through retrospective evaluation by a close relative of each patient. One aim of the study was the development of a psychometric instrument in order to construct clinically relevant scales, which would allow us to objectify characterizations of the premorbid personality of patients with psychic illness. Another aim was to test the validity of this instrument by investigating the coherence between the obtained test results and the corresponding clinical psychiatric judgments of experts in the form of diagnoses. Finally, we sought to determine if typical premorbid characteristic features give a predisposition for specific aspects of psychotic diseases, in order to be able to differentiate between diverse psychiatric groups of diagnoses. By means of factor analysis (principal component analysis) with Varimax rotation we came to five easily distinguishable clinical-psychological well interpretable factors, from which we derived five scales. These scales seem to be appropriate for the characterization of premorbid personality traits. They represent the following clinical concepts: (1) cyclothymia, (2) sthenia, (3) anancasm, (4) hostility, (5) schizothymia. Formal examination of the factor-analytical proved scales according to criteria of classic test-theory (item-test correlation, reliability, distribution, intercorrelation) showed that we were able to measure rather independent dimensions of premorbid personality by our five scales with sufficient accuracy. To get evidence for the empirical validity of our scales we compared our test results (1) with three groups of different diagnoses concerning premorbid personality and (2) with the two diagnostic groups of schizophrenia and affective psychoses. We also tried to work out differential aspects within the diagnostic group of schizophrenia for four subgroups. As criteria for validity we sued clinical judgments of psychiatrists both for the premorbid personality and for the diagnosis of the present disease. On the whole our adjective check list turned out be as useful instrument to get a discriminating description of premorbid characteristic features which is better than a global evaluation in form of a single diagnosis. First First indications of the practical importance of our scales are discussed.