The Reliability, Validity and Utility of a Diagnosis in Schizophrenia

This paper reviews the literature available regarding the reliability, validity and clinical utility of a schizophrenia diagnosis. Schizophrenia is a complex and typically chronic mental illness, with diagnosis being based on symptoms, not unlike many psychiatric illnesses. The reliability, validity and utility of the diagnosis of schizophrenia have been debated, often controversially, and sometimes challenged with misinformation. The reliability of schizophrenia diagnoses is excellent when a structured interview is used, but can be poor in routine clinical practice. The diagnosis of schizophrenia is hindered by the lack of objective diagnostic tests, however, the concept has face and predictive validity, with progress in genetics and neuroimaging providing some biological and concurrent validity. It is clear that the diagnosis has high clinical utility globally, similar to many psychiatric and medical conditions. Overall, schizophrenia is comparable to medical diagnoses made clinically, in that the diagnosis enables evidence-based treatment and improves patient outcomes.