Another major focus of behavioral medicine research is the relationship between personality factors and illness. Interest in this relationship dates back at least to the ancient Greeks, who classified people into one of four basic personality types (phlegmatic, melancholic, sanguine, and choleric); these personalities were presumed to be based on imbalances in bodily fluids, or humors. Early in this century, it was believed that certain diseases, such as hypertension, heart disease, cancer, asthma, ulcerative colitis, and ulcers, were "psychosomatic"—mainly caused by personality. As research data have accumulated, however, it has become clear that the association between personality and illness is much more complex than first believed. Current research examines the impact on health of psychological constructs such as motivation, self-mastery, and self-confidence, as well as the impact of alcohol and substance abuse. Related factors under study include socioeconomic status, gender, and cognitive status.
Since the early 1950s, one major focus of psychosomatic research has been the relationship between the "Type A" personality and cardiovascular disease. Two cardiologists originally described a cluster of characteristics that many of their patients shared. People with Type A personalities were described as highly competitive and achievement oriented. They are also typically in a hurry and impatient; in addition, they are hostile in social interactions.
Major longitudinal studies in the 1960s and 1970s convincingly supported the notion that the Type A personality was a major risk factor for developing cardiovascular disease. In 1981, a panel organized by the National Heart, Lung, and Blood Institute (NHLBI) concluded that Type A behavior was a risk factor for coronary heart disease (CHD). Since that time, however, several large, well-conducted studies (including the long-term follow-up to the original study which found a Type A-heart disease link) have found no association between Type A behavior and heart disease.
Researchers have proposed several possible explanations for the Type A turnabout. These include that (1) the original findings were just a fluke; (2) the assessment of Type A may have changed over time; (3) society may have changed, making the Type A distinction anachronistic; (4) coronary heart disease population distribution has changed (changing patterns of smoking, diet, and physical activity may interact with Type A behavior in unclear ways); or (5) some aspects of Type A behavior are risk factors, but others are not. Many studies have examined this latter possibility.
In one comprehensive meta-analysis examining the effects of psychological and behavioral variables on coronary heart disease, only the anger and hostility components of Type A were found to be significant CHD risk factors. Overall, Type A was unrelated to future disease status. Other studies, using both the Type A Structured Interview and the Cook-Medley Hostility (Ho) Scale of the Minnesota Multiphasic Personality Interview (MMPI), have found that "cynical hostility'' is predictive of future coronary disease morbidity and mortality. People who are cynically hostile tend to expect the worst of others and dwell on people's negative characteristics. This personality characteristic, unlike overall Type A behavior, does seem to predict future heart disease.
When considering the Type A and CHD research, it is important to note that the majority of research has been conducted with male subjects. Relatively little attention has been paid to CHD risk factors in women, despite the fact that CHD is the leading cause of death among women, killing more women than men each year. Only recently have researchers begun to examine the personality risk factors for women.
The relationship between hostility and diseases other than CHD has also been examined. A number of studies, for example, have found a link between hostility and all-cause mortality. Only one study, however, has controlled for CHD deaths in the analysis. In that study, MMPI Hostility scores correlated with 20-year, all-cause mortality rates, even when CHD-related mortality was factored out. To date, no studies have linked hostility to other major health outcomes, such as cancer.
Besides hostility, many other personal factors have been examined for their relationship to health. Notably, clinical and nonclinical depression have been related to poor health outcomes among certain disease groups. In one study of CHD and depression, clinical depression assessed in recently hospitalized post-
Behavioral Medicine myocardial infarction (MI; or heart attack) patients was associated with a 500% greater likelihood of 6-month mortality. In another study, 4000 hypertensive individuals were followed for 4.5 years. In this group, change in depression level (although not absolute level) predicted future cardiac events like infarctions and surgeries.
Other studies have shown that having an optimistic, rather than pessimistic, attitude may have important health consequences. Similarly, a negatively fatalistic outlook on life and health may be a prognostic indicator of poor future health status. In one 50-month study of 74 male patients with AIDS, increased survival time was significantly associated with low levels of fatalism, which was called "realistic acceptance." Patients who had low scores on a measure of realistic acceptance had median survival times 9 months longer than patients with high levels. When potential confounds were controlled for, such as initial health status and ongoing health behaviors, the effect remained significant.
Similar findings have been obtained with other disease groups. Researchers often use all or part of the Life Orientation Test (LOT) as a measure of optimism and pessimism. In one study, a pessimistic attitude (as measured by LOT) was a significant mortality risk factor for young adults with recurrent cancer. Another study found that high LOT pessimism was associated with greater risk of MI during coronary artery bypass graft (CABG) surgery.
Another area of inquiry regarding personal factors and health involves recovery and adaptation after surgery. Researchers assessed a number of psychosocial variables in a population of 42 leukemia patients about to receive allogeneic bone marrow transplants. (Allo-geneic transplants involve bone marrow from donors other than themselves or identical twins.) Participants who had an attitude toward cancer characterized by "anxious preoccupation" had increased mortality compared to nonanxious participants.
Finally, socioeconomic status (SES) has emerged as an important determinant of health status. Several studies have shown a clear gradient between SES and a variety of different indicators of health status. Furthermore, the association is continuous. For example, there are differences in health status between moderately poor people and those who are very poor. On the other end of the spectrum, it appears that there are differences between the very rich and those who are moderately well off. These differences are observed in nearly all cultures, including those with universal access to health care. Thus, health care alone does not seem to explain the association between SES and health status.
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