[A computer algorithm for diagnostic assessment with DSM-III in the early course of schizophrenic diseases]

The purpose of the computer algorithm described here is the evaluation of diagnostic criteria according to DSM-III for schizophrenia and schizophreniform disorders. It also dates the first time point of the assessment of these diagnoses. The necessary information comes from a semistructured interview, called IRAOS (Interview for the Retrospective Assessment of the Onset of Schizophrenia). With this interview early indicators of a beginning schizophrenia can be evaluated in their chronological order and their type of course. The algorithm was first used in a sample of patients admitted for the first time with a diagnosis of either schizophrenia or paranoid psychosis. One third of these patients fulfills the DSM-III-criterion of a duration of at least six months. The other patients fulfill criterion B of a schizophreniform disorder. To strengthen the validity of a diagnosis including the criteria A up to E successively, the sample is reduced to 70%. The average time point of the first assessment of the diagnosis by the computer algorithm is about 1.5 years before the index-admission. Together with the IRAOS the computer algorithm allows an operationalized assessment of the real onset of schizophrenia.