Most people are familiar with the idea of the “Type A” person—someone intensely competitive, impatient, and aggressive. And we are often quick to identify this person as being at high risk for cardiovascular disease: “he’s going to have a coronary sitting in that traffic jam;” or “her blood pressure went through the roof when she saw the mess the kids had made.” And while there is some evidence that certain aspects of a Type A personality may increase the risk for cardiovascular disease, it is less clear if this risk extends to the second leading cause of death—cancer.

The studies on cancer and personality have been mixed. Some have suggested that certain traits, such as extraversion, hopelessness, or lack of emotion, are linked to a greater incidence of cancer. However, others have found no association at all. In a paper published in the June 4, 2003 issue of the Journal of the National Cancer Institute , a group of researchers in Japan present their findings on this topic—that personality has no affect on cancer risk.

About the Study

In the summer of 1990, a group of researchers from the Tohoku University graduate schools of medicine and education in Japan gave two questionnaires to 51,921 people (ages 40-64) living in rural Northern Japan. The first questionnaire collected health information, such as the following: personal and family medical history (including cases of cancer); health habits, such as smoking, alcohol use, diet, and use of health care services; and height and weight.

The second questionnaire—the Japanese version of Eysenick Personality Questionnaire-Revised (EPQ-R) Short Form—rated respondents on four personality types. Based on their answers, the respondents were given a score of 0-12 for each personality type, with a higher number indicating a greater tendency toward that type. The four types and their characteristics are as follows:

  • Extraversion – sociability and liveliness
  • Neuroticism – emotional instability and anxiousness
  • Psychoticism – tough-mindedness, aggressiveness, coldness, and egocentricity
  • Lie – hypocrisy (pretending to be something one is not) and naiveness (lacking wisdom or informed judgment)

In 1997, the researchers looked at who developed cancer in the seven years since the surveys were given. They compared the rates of cancer among personality groups and calculated the risk of cancer based on personality. Incidences of all types of cancer were considered as well as the four most common types in Japan: stomach, colorectal, lung, and breast.

The researchers conducted their final analysis on the surveys of 29,606 people; those who were excluded had not completed the surveys or did not meet other eligibility criteria. The researchers adjusted their findings to account for the effects of cigarette smoking, alcohol intake, weight (body mass index), level of education, and family history of cancer.

The Findings

None of the four personality types were associated with an increased risk of cancer incidence. This lack of association held true for all cancers as well as for the four specific cancers examined (stomach, colorectal, lung, and breast).

While this study found no connection between personality type and cancer, it may not be the final word on this topic. Four general personality types were considered here, but there could be other personality traits that are associated with cancer risk. Also, the researchers noted that while their study group was quite large, the number of cancers was “modest at best.” Therefore, a greater number of cancer cases may be necessary to see trends in personality type and risk, if any truly exist.

How Does This Affect You?

The theory that personality can affect the risk of cancer is quite intriguing, as certain personality traits are under our control. And there is considerable evidence that our thoughts, feelings, and attitudes have a direct affect on our immune system, which plays a significant role in the development of cancer. However, the results of this study indicate that whether you are anxious or mellow, social or shy, loving or aloof, your risk of cancer will not be affected. This may not be true, of course, for cardiovascular disease or other serious conditions.

For your own quality of life (and for those close to you), it is worth “improving,” or at least compensating for, your personality type. For example, if you are anxious, consider meditation or counseling . If you tend to be aggressive, seek positive outlets for this energy, such as regular exercise . But for the sake of reducing your risk of cancer, stick with the known methods: