Diagnosis of secondary depression in schizophrenia

Four diagnostic groups were studied to determine the relationship of depression secondary to schizophrenia to DSM-III major depression criteria and Hamilton Depression Rating Scale scores. The symptoms found in schizophrenic patients with major-type depressions differed qualitatively from those in primary depressives. Some of the criteria used to diagnose depression in schizophrenic patients (retardation and insomnia) probably arise from the schizophrenic syndrome. Since secondary depression in schizophrenia is associated with poor outcome, it is important that specific diagnostic criteria for distinguishing depressed from nondepressed schizophrenics be developed. Such criteria should not include symptoms that are part of the schizophrenic syndrome.