Intelligence and Personality May Predict Illness and Death

Do smarter people live longer and better lives? Are certain personality types more prone to premature death than are others? As our population continues to age in dramatic numbers, these questions become increasingly relevant. A new report in Psychological Science in the Public Interest, a journal of the Association for Psychological Science, provides an overview of research on possible associations between intelligence and personality traits and various health outcomes. 

Although there is not much evidence to date that links intelligence with cancer, low intelligence has been shown to be related to increased risk of hospital admission and death due to cardiovascular disease. In addition, lower intelligence is associated with a greater incidence of accidents and risk of death by homicide than is higher intelligence.  

The report, authored by Ian J. Deary and Alexander Weiss of the University of Edinburgh, and G. David Batty of the Medical Research Council Social and Public Health Sciences Unit in Glasgow, also cites evidence that personality may be associated with coronary heart disease. For example, cardiac patients with a distressed “Type D” personality, characterized by negative emotions and social inhibition, are at greater risk for poorer outcomes, including death. 

Conscientiousness has been identified in many studies as the key personality trait that is a predictor of longevity: The more conscientious an individual is, the longer he or she tends to live. A review of more than 190 studies showed that “high conscientiousness was consistently related to more health-promoting behaviors (e.g., exercise, healthy diet) and fewer health-harming ones (e.g., alcohol abuse, fast driving).”

These results have important implications for the physician’s office because physicians may be better able to determine appropriate treatments if they take their patients’ personalities into account. For example, a conscientious patient may be more likely to adhere to a complex treatment regimen than a less conscientious patient. Or a patient low in intelligence who also has a distressed personality type could have their cardiovascular health monitored more frequently than a patient with higher intelligence and a more agreeable personality. 

Although studies indicate there may be important connections between intelligence and personality with health outcomes, the authors suggest that future studies should focus on identifying and ruling out potential mediators and moderators since they may be modifiable risk factors. The authors also note the potential value of using animal models: A number of traits can be measured in nonhuman species and controlling factors such as diet and environment may improve understanding in how these traits impact health directly.