[The Validity and Reliability Study of the Dokuz Eylül Theory of Mind Index (DEZİKÖ) in Patients with Schizophrenia].

OBJECTIVE Although a lack of a comprehensive theory of mind (ToM) index has been indicated frequently in studies of schizophrenia spectrum disorders, there is no valid and reliable index to assess ToM, which represents the ability to attribute mental states to other people. The purpose of this study is to examine the validity and reliability of the "Dokuz Eylul Theory of Mind Index" (DEZIKÖ) in healthy volunteers and in patients with schizophrenia, which is the first Turkish-language ToM index, developed using examples in the ToM literature. METHOD The study sample consisted of a total of 286 participants, including 89 patients with schizophrenia who had been diagnosed by DSM-IV and 197 healthy volunteers. Sociodemographic data form and DEZIKÖ were administered to all participants. Empathic Skill Index-B Form (EBÖ-B) and Positive and Negative Syndrome Scale (PANSS) were administered to the patients. RESULTS In healthy volunteers, internal consistency coefficient of DEZIKÖ was 0.64; inter-rater reliability was 0.99 (p<0.0001) and testretest reliability was 0.90 (p<0.01). The patient group had a positive significant correlation between DEZIKÖ and EBÖ-B (r=0.43, p<0.05). Furthermore, it was shown that healthy volunteers and patients with schizophrenia can be distinguished by using DEZIKÖ (t(285)=8.74, p<0.01). The results of factor analysis with principal components analysis in the healthy volunteer group verified that DEZIKÖ has 3 factor groups. CONCLUSION These findings indicated that DEZIKÖ, the first ToM index in the Turkish language, has acceptable validity and reliability values in healthy volunteers and in patients with schizophrenia.