In psychiatric treatment, differences between therapists' observer ratings and patients' self-ratings are well known. We studied these differences in a sample of chronically mentally ill outpatients. The results show that the patients rated their psychosocial status significantly better than their therapists. By means of multiple regression analysis, we designed a model to explain the specific differences. By placing more emphasis on leisure activities and less emphasis on addictive behavior, compliance, and psychopathology, therapists might predict global ratings given by patients more accurately. This model helps therapists obtain a better understanding of their patients.