Background and objective: Until now there has not been a validated measure of theory of mind available in the Thai language. Our goal in this study was to assess the validity and reliability of our Thai-language translation of the Reading the Mind in the Eyes Test (the "Eyes Test").
Methods: We gave our Thai version of the Eyes Test to 70 participants: 30 people with schizophrenia and 40 normal controls. We also gave Thai versions of the Faces Test and the Addenbrooke's Cognitive Examination to assess convergent validity.
Results: For known groups validity, the controls scored significantly higher than the participants with schizophrenia on the Eyes Test: 24.6 (standard deviation=3.9) versus 18.2 (standard deviation=4.1), P<0.001. The Eyes Test correlated with the Addenbrooke's Cognitive Examination (r=0.68, P<0.001) and the Faces Test (r=0.51, P<0.001). Internal consistency by the Cronbach alpha for the Eyes Test was 0.7, and test-retest reliability by intraclass correlation was 0.92 (P<0.001).
Conclusions: The Thai version of the Eyes Test is a valid and reliable measurement that can be used in clinical practice and in future investigations of theory of mind in neurologic and psychiatric disorders.