When it comes to helping young adults avoid serious health problems later in life, assessing their personalities during routine medical exams could prove as useful as recording their family medical histories and smoking habits, according to new research published by the American Psychological Association.

"Health care reform provides a great opportunity for preventive care, with physicians seeing more young adults who may not previously have had insurance," said lead author Salomon Israel, PhD, of Duke University and Duke University Medical Center. "Our research found that if a doctor knows a patient's personality, it is possible to develop a more effective preventive health care plan that will result in a much healthier life."

APA Executive Director Norman B. Anderson, PhD, said this study provides more evidence of the benefits of integrated health care. "The best health care is one that treats the whole person including how their personality traits impacts their attitudes and behaviors vis-à-vis their health," said Anderson, who is also director of APA's Center for Psychology and Health.

Being conscientious appears to be the best bet for good health among traits known as the "Big Five," which are the basis for most psychological personality assessments. Along with conscientiousness, the Big Five include extraversion, agreeableness, neuroticism and openness to experience. Participants who were more conscientious when they were 26 years old were more likely to be in much better health at age 38 than those who were low in that personality trait, the study found.

"Among the least conscientious, 45 percent went on to develop multiple health problems by age 38, while just 18 percent of the most conscientious group developed health problems," Israel said. "Individuals low in conscientiousness were more often overweight, had high cholesterol, inflammation, hypertension and greater rates of gum disease."

Conscientious people are more likely to have active lifestyles, maintain healthy diets and have more self-control, so are less likely to smoke or abuse alcohol and drugs, the study noted. This could explain the apparent relationship between that trait and better health, the researchers said. A surprising find was that being neurotic at age 26 was not linked to poorer physical health at age 38, contrary to some theories that aspects of neuroticism such as stress and anxiety can lead to ill health. This was the case even though the neurotic participants rated themselves in poorer health at the later age, according to the study.

Researchers examined data from a Dunedin, New Zealand health and development study involving 1,037 people born between April 1972 and March 1973. Slightly more than half the subjects were male. The participants were assessed about every two years from birth until they were 38 years old. At age 26, the participants nominated a person who knew them well, such as a parent, spouse or friend, to describe them using the Big Five traits. Researchers also gathered participants' clinical health information and risk factors commonly recorded in primary care offices, including income, education, smoking, obesity, current and past illnesses and family medical history.

At age 32, the participants' personalities were again assessed on the Big Five scale, but this time in a clinical setting with ratings by the clinic receptionist and nurse who were not aware of the study's focus. This brief clinical assessment yielded similar results to those done by people who knew the participants well when they were 26 years old, according to the study. At age 38, the participants had physical exams that checked for abnormalities of liver and kidney functions, blood pressure, heart and lung fitness, vascular inflammation and periodontal disease.

"Personality traits can be measured cheaply, easily and reliably, and these traits are stable over many years and have far-ranging effects on health," said Israel. "Our findings suggest that in addition to considering 'what' a patient has among risks for chronic age-related diseases, physicians can benefit from knowing 'who' the patient is in terms of personality in order to design effective preventive health care."