"A pessimistic personality trait measured early in life (ages 20-39 years) was a particularly strong predictor of increased mortality," concludes the report, which has just been published in the journal Psychosomatic Medicine.
"We found an increased risk of death for subjects with elevated scores on the scales for pessimistic, anxious and depressive personality traits considered separately, and for subjects with elevated composite neuroticism scores," the researchers report.
Furthermore, those whose negative traits were more pronounced were still more likely to die than those with milder neurotic predispositions. The findings were similar for men and women.
The research team led by Walter A. Rocca examined data from 7,080 people treated at the clinic between the years 1962 and 1965. While at the facility, all of them completed the Minnesota Multiphasic Personality Inventory, a self-administered questionnaire in which they answered "true" or "false" to 550 statements concerning their thoughts, feelings, attitudes and life experiences.
The patients, all of whom lived within a 120-mile radius of the Rochester, Minn., facility, had a median age of 48 at the time they completed the personality assessment. Seventy percent reported they were in good general health.
Over the following four decades, their health was tracked using a combination of telephone interviews and reviews of their medical records or death certificates. Just over 65 percent of them died during that period.
The reasons for the correlation between neuroticism and mortality "remain uncertain and are probably complex," say the researchers, who propose three possible causes:
- A direct biological link between personality and health. The researchers note that stress and depression have been correlated with such physical problems as hypertension and lower immune system responsiveness.
- Negative personality traits "may lead to poor self-care or to unhealthy behaviors," which hasten death.
- Underlying neuroticism may "modify the prognosis of diseases after their onset." In other words, people prone to anxiety or depression may assume the worst when given a diagnosis, and put less effort into treatment.
"It is likely that all three mechanisms may be involved in combination," they conclude.
The scholars note that if one or more of these causal links are confirmed, "our findings may prompt interventions to improve health and increase survival." Their work suggests that, for some patients, cognitive behavioral therapy to counteract negative self-talk may be as vital as any other component of treatment.