OBJECTIVE: The goal of this study was to clarify more precisely where patients with psychotic disorders and the mental health professionals who care for them disagree regarding whether the patient is ill or needs treatment. METHOD: The authors prepared brief vignettes in everyday descriptive language that provided examples of the classical positive and negative psychopathological features of schizophrenia. Fifteen men and 11 women diagnosed as having schizophrenia or schizoaffective disorder and one physician used these vignettes as a common frame of reference to rate 1) the degree to which the patients demonstrated the features described in each vignette and 2) the degree to which the features signified the presence of mental illness. RESULTS: Disagreements between the physician's and patients' ratings, indicating deficits in insight, were associated with the recognition of the presence of conceptual disorganization, avolition-apathy, and affective blunting in the patients by the physician but not the patients and with the conceptualization of hallucinatory behavior and suspiciousness as signs of mental illness by the physician but not the patients. CONCLUSIONS: The authors conclude that the failure to acknowledge conceptual disorganization, avolition-apathy, and affective blunting and the failure to view hallucinatory behavior and suspiciousness as signs of mental illness, which proved to be additive in this study, contribute to deficits in insight.Abstract Teaser