Clinical predictors of discrepancy between self-ratings and examiner ratings for negative symptoms

Little is known about the awareness of negative symptoms or its correlates. The aim of this study was to examine whether a number of clinical variables can predict the discrepancy between ratings of negative symptoms made by schizophrenic patients and by an examiner. This discrepancy could provide a measure for the awareness of negative symptoms. Eighty-six schizophrenic patients used a self-rating scale for negative symptoms with items derived from the Scale for the Assessment of Negative Symptoms (SANS). A psychiatrist assessed all patients using the SANS and other instruments, including the Present State Examination (PSE) item "insight into psychotic condition." Nurses assessed all patients using the Rehabilitation Evaluation Hall and Baker (REHAB), a scale for the measurement of psychiatric disability. All measurements were repeated after 2 months. A sensitive index for the underestimation of the severity of negative symptoms was developed, the discrepancy score. Multiple regression analysis was used to examine the predictability of discrepancy scores. Since scores for SANS items were used to calculate discrepancy scores, all regression analyses were performed with the SANS summary score as a covariate. The first step was to assess the independent contribution of each variable to the prediction of discrepancy scores. The second step was to examine the predictive quality of the 19 variables together. The variables themselves failed to make an independent contribution to the prediction of discrepancy scores at both assessments. REHAB scores, for instance, contributed to the prediction of discrepancy scores at the first assessment, but not at the second. The results of the second step showed that the best model for the prediction of discrepancy scores included the variables of depression (negative association) and anxiety (positive association). The absence of an association with the PSE item suggests that the awareness of negative symptoms is not related to insight into positive symptoms. An important limitation of our study is the arbitrary method of discrepancy quantification.