Objective: Type D personality is based on negative affectivity (NA) and social inhibition (SI). The purpose of this study was to examine the reliability and validity of the Persian version of 14-item Type D personality scale (DS14).
Methods: The study included 191 normal participants and 176 patients with myocardial infarction (MI). They all filled out the Persian version of DS14, containing 7-item NA and SI subscales; 71 normal subjects completed the neuroticism and extroversion subscales of Eysenck questionnaire. Besides, 71 participants filled out the DS14 twice over a 2-month period.
Results: In this study, 35.8 % of MI patients and 24.6% of healthy people were classified as Type D. Factor analysis of Persian version of DS14 yielded the two-factor structure; all of the NA and SI items loaded between 0.65 to 0.80 in patients and 0.48 to 0.79 in healthy people on their corresponding factor. Test-retest stability of the NA and the SI subscales were 0.86 and 0.77 respectively over a 2-month period. High internal consistency of Cronbach's alpha coefficient has been found to be 0.84 in patients and 0.87 in healthy people for the NA sub-scale and 0.86 in patients and 0.75 in healthy people for the SI sub-scale. The construct validity of NA and SI sub scales were confirmed against neuroticism (r = 0.65) and extroversion (r = -0.62) subscales of Eysenck questionnaire respectively.
Conclusion: Persian version of DS14 is an acceptable, reliable and valid measure of dimensions of Type D personality.
Keywords: Myocardial Infarction; Negative affectivity; Psychometric Properties; Social inhibition; Type D Personality Scale.