[Reliability and validity of the schedule for deficit syndrome in schizophrenia].
OBJECTIVE: The Schedule for Deficit Syndrome (SDS) is an instrument for categorizing schizophrenic patients as those with and without deficit syndrome. This schedule has been translated and adapted into the Turkish language in order to study its reliability and validity. METHOD: 30 male schizophrenic patients were included in the study. The patients had been ill for a long period of time and the course was continuous. The patients were assessed by two different raters using the SDS as a means of testing its reliability. A third rater assessed the same group of patients using the BPRS to test the validity of the SDS. RESULTS: The raters using the SDS demonstrated good inter-rater reliability for the categorization of patients with and without deficit syndrome, as well as for rating global severity (kappa: 0.88-0.93) and individual negative symptoms (kappa: 0.51-0.61). The schedule was also found to have a high validity for both categorization and measuring individual negative symptoms. (U: 60.0, P: 0.03). CONCLUSION: The results demonstrated that the Turkish version of the SDS would be a reliable and valid instrument that could be used in the study of schizophrenia.