Psychometric Properties of the DS14 and Associations with Ill Health and Coronary Heart Disease in General and Clinical Populations

Condén, E. 2014. Type D Personality. Psychometric Properties of the DS14 and Associations with Ill Health and Coronary Heart Disease in General and Clinical Populations. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 1034. 74 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9052-2. Type D personality, or distressed personality, refers to the joint tendency to experience negative emotions and to inhibit self-expression in social interactions. The overall aims of this thesis were to examine the impact of Type D personality on adolescents’ self-perceived health, to examine the factorial and temporal stability of the Type D personality construct DS14, and to clarify whether type D personality is an independent risk factor for recurrent myocardial infarction and all-cause mortality among patients with myocardial infarction. The prevalence of Type D personality in the adolescent population was 10.4% for boys and 14.6% for girls. Boys and girls with Type D personality were approximately twice as likely to report musculoskeletal pain and five times as likely to report psychosomatic symptoms. Adolescents with Type D personality were four times more likely to have sleep disturbances and to sleep fewer hours, especially on school nights. Among patients with myocardial infarction, the Swedish DS14 had stable structural validity. Our measurements confirmed the two-factor model of the DS14. However, the DS14 exhibited low temporal stability, especially when comparing the measurement obtained during hospitalization with the 1and 12-month follow-up measurements. Among patients with myocardial infarction, the Framingham risk score had a strong predictive value for recurrent myocardial infarction, and a somewhat weaker predictive value for all-cause mortality. However, none of the previously proposed methods for the analysis of the DS14 Type D personality measurement predicted recurrent myocardial infarction or allcause mortality, either in univariable analyses or in addition to the Framingham risk score. In conclusion, the present thesis found significant associations between the DS14 and psychosomatic symptoms in adolescents. However, the measurement exhibited a low stability over time and no predictive value for recurrent myocardial infarction and mortality among patients with myocardial infarction. Taken together, these results raise the question of whether the Swedish DS14 really is a measure of personality. An alternative explanation for the strong cross-sectional associations observed between the DS14 and psychosomatic symptoms might be that the DS14 functions as a pseudo-measure of ill health, or co-varies with depressive or psychosomatic characteristics.