Personality and tonic cardiovascular, neuroendocrine, and immune parameters.

Although there is now abundant evidence that certain personality features constitute risk factors for negative health outcomes, personality measures have received little attention to date in the behavioral immunology literature. The present study assessed the relationship between major dimensions of personality and tonic cardiovascular, neuroendocrine, and immunologic parameters in 276 healthy adults. Participants who scored low in agreeableness tended to have higher levels of systolic blood pressure, diastolic blood pressure, and epinephrine. Low levels of extraversion were associated with higher blood pressure, epinephrine, norepinephrine, and natural killer cell cytotoxicity. Neuroticism was generally unrelated to physiologic outcomes. Personality was not associated with leukocyte subset counts. The magnitude of relationships between personality and physiology was modest, with personality measures accounting for 1 to 7% of the variance in selected physiological parameters. Health practices did not mediate associations between personality and physiologic outcomes. However, a substantial proportion of the relationship between extraversion and natural killer cell cytotoxicity was accounted for by their common association with epinephrine and to a lesser extent norepinephrine. These findings are consistent with the notion that personality contributes to basal physiology and provide a foundation for further research on the relationship between personality and natural killer cell cytotoxicity.