Diagnosis of schizophrenia.

Case records of ninety consecutive first lifetime admissions with a hospital diagnosis of schizophrenia were examined for Schneiderian first rank symptoms, the Feighner diagnostic criteria, and the New Haven Schizophrenia Index. Diagnostic exclusion criteria were developed and applied. It is concluded that the hospital diagnosis of schizophrenia is likely to be too broad. Each diagnostic system can increase accuracy of diagnosis, but their exclusion criteria are too vague and the system would be improved by using those given here. Each diagnostic system selects similar groups of patients, and can be applied retrospectively to adequate case records.