Factors influencing the validity of relatives' reports about symptoms of first-episode schizophrenia

Valid information on the early course of schizophrenia is necessary for clinical and research purposes, for example, to determine the onset of the disorder. Since reports given by psychotic patients are questionable, relatives are often asked about their observations. In order to test the quality of these reports, the recollections of emerging symptomatology were assessed systematically from 30 recent onset, postpsychotic schizophrenic patients and from 69 informants (mostly their close relatives) by means of the Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS). Patient-informant agreement rates like kappa were compared between the relatives of every single case. Multiple regression analyses demonstrated that personality and attributional factors, particularly causal attributions and the image the informant has about him/herself and about the patient, determine the quality of the informants' reports. Highest kappas over all symptoms, for instance, were reached by relatives who described the patient as "dominant" and themselves as "reserved", and who attributed the disease to current psychosocial stress. Long and close contact to the patient tends to impair the quality of reports.