People with more conscientious personalities, who have greater ambition and discipline, live longer. That's according to Margaret Kern and Howard Friedman who combined data on this topic from over 20 previous studies, involving more than 8,900 participants in the United States, Canada, Germany, Norway, Japan and Sweden - many of whom had illnesses like heart disease or cancer.
On average, people who scored higher on measures of conscientiousness (agreeing, for example, with statements like "I plan ahead" and disagreeing with statements like "My house is a mess") tended to live between two and four years longer than low scorers.
This influence of conscientiousness on longevity was found to be as large or larger than many better known factors affecting longevity, such as socio-economic status.
Among the sub-factors of conscientiousness, it was ambition and discipline that were particularly important for longevity, whereas responsibility and self-control were less important.
Past research has shown that people who are more conscientious are less likely to drink or smoke heavily but health behaviours aren't the whole story. For example, a previous study by the same research team found that conscientiousness measured in childhood predicted longevity over a 70-year period, regardless of whether the cause of death was health-related or not. Kern said it's possible that as well as affecting health behaviours, conscientiousness also influences the kind of people we end up mixing with and the situations we find ourselves in.
The researchers said that personality factors are too often ignored in a medical context and that their findings could one day have practical implications. “There is some evidence that people can become more conscientious, especially as they enter stable jobs or good marriages,” Kern said. “We think our findings can challenge people to think about their lives and what may result from the actions they do. Even though conscientiousness cannot be changed in the short term, improvements can emerge over the long run as individuals enter responsible relationships, careers, and associations.”
Margaret L. Kern, Howard S. Friedman (2008). Do conscientious individuals live longer? A quantitative review. Health Psychology, 27 (5), 505-512 DOI: 10.1037/0278-622.214.171.1245