Type D personality-a joint tendency toward negative affectivity (NA) and social inhibition (SI)-is related to poor cardiac prognosis, but there is no standard for assessing Type D. This study reports on the Type D Scale-14 (DS14) as a standard measure of NA, SI, and Type D. The study included 3813 participants (2508 from the general population, 573 cardiac patients, 732 hypertension patients). They all filled out the DS14, containing 7-item NA and SI subscales; 275 subjects also completed the NEO-FFI, and 121 patients filled out the DS14 twice. Factor analysis of the DS14 yielded 2 dominant traits; all of the NA and SI items loaded between 0.62 to 0.82 on their corresponding factor (N = 3678). The NA scale covered dysphoria, worry, and irritability; the SI scale covered discomfort in social interactions, reticence, and lack of social poise. The NA and SI scales were internally consistent (alpha = 0.88/0.86; N = 3678), stable over a 3-month period (test-retest r = 0.72/0.82) and not dependent on mood and health status (N = 121). NA correlated positively with neuroticism (r = 0.68); SI correlated negatively with extraversion (r = -0.59/-0.65). Scale-level factor analysis confirmed the construct validity of the DS14 against the NEO-FFI. Using a cutoff of 10 (NA > or =10 and SI > or =10), 1027 subjects (28%) were classified as Type D, 21% in the general population versus 28% in coronary heart disease and 53% in hypertension (p < or = .001). Age, sex, and Type D (odds ratio, 3.98; 95% confidence interval, 3.2-4.6; p <.0001) were independently associated with cardiovascular morbidity. The DS14 is a brief, psychometrically sound measure of negative affectivity and social inhibition that could readily be incorporated in epidemiologic and clinical research.