The interaction of Type A behavior and social support in relation to the degree of coronary artery disease (CAD) severity was investigated. One hundred thirteen patients undergoing diagnostic coronary angiography received the Type A structured interview (SI) and completed a battery of psychometric tests, including the Perceived Social Support Scale (PSSS). Statistical analyses revealed a Type by social support interaction, such that the probability of significant CAD was inversely related to the level of social support for Type As but not Type Bs. Type As with low levels of social support had more severe CAD than Type As with high levels of social support. On the other hand, this relationship was not present for Type Bs. These results are consistent with the hypothesis that social support moderates the long-term health consequences of the Type A behavior pattern.

Type A behavior pattern was assessed using the structured interview and hostility level was assessed using a subscale of the Minnesota Multiphase Personality Inventory in 424 patients who underwent diagnostic coronary arteriography for suspected coronary heart disease. In contrast to non-Type A patients, a significantly greater proportion of Type A patients had at least one artery with a clinically significant occlusion of 75% or greater. In addition, only 48% of those patients with very low scores (less than or equal to 10) on the Hostility scale exhibited a significant occlusion; in contrast, patients in all groups scoring higher than 10 on the Hostility scale showed a 70% rate of significant disease. The essential difference between low and high scorers on the Hostility scale appears to consist of an unwillingness on the part of the low scorers to endorse items reflective of the attitude that others are bad, selfish, and exploitive. Multivariate analysis showed that both Type A behavior pattern and Hostility score are independently related to presence of atherosclerosis. In this analysis, however, Hostility score emerged as more related to presence of atherosclerosis than Type A behavior pattern. These findings confirm previous observations of increased coronary atherosclerosis among Type A patients. They suggest further that an attitudinal set reflective of hostility toward people in general is over and above that accounted for by Type A behavior pattern. These findings also suggest that interventions to reduce the contribution of behavioral patterns to coronary disease risk might profitably focus especially closely on reduction of anger and hostility.

Previous research has linked the Type A coronary-prone behavior pattern to angiographically documented severity of coronary atherosclerosis (CAD). The present study sought through component scoring of the Type A Structured Interview (SI) to determine what elements of the multidimensional Type A pattern are related to coronary disease severity in a selected group of patients with minimal or severe CAD. Multivariate analyses controlling for the major risk factors showed no relationship between global Type A and extent of disease. Of all attributes measured, only Potential for Hostility and Anger-In were significantly and positively associated with the disease severity, including angina symptoms and number of myocardial infarctions. Further analysis revealed that Potential for Hostility and Anger-In were interactive in their association, such that Potential for Hostility was associated with disease endpoints only for patients who were high on the Anger-In dimension. These findings support previous research in suggesting that anger and hostility may be the critical aspects of the Type A pattern in predisposing individuals to risk of CAD.