Personality may influence reactivity to stress.

Background: Possible mechanisms behind psychophysiological hyperreactivity may be located at a cognitive-emotional level. Several personality traits have been associated with increased cardiovascular reactivity. Subjects with white coat hypertension, which may constitute a kind of hyperreactivity, are found to suppress their emotions and adapt to the surroundings to a larger extent than controls.We hypothesized in this study that a) stress reactivity is related to personality, and that b) responses to cold pressor test (CPT) and mental stress test (MST) are associated with different personality traits.

Methods: 87 men were selected from the 1st, 50th and 99th percentile of a blood pressure screening. Cardiovascular and catecholamine responses to MST and CPT were recorded. Fifteen personality traits were assessed using the Karolinska Scale of Personality. Possible independent explanatory predictors for cardiovascular and catecholamine variables at baseline and during stress were analyzed in multiple linear regression analyses using a stepwise forward procedure.

Results: Multiple regression analyses showed that muscular tension (beta = 0.298, p = 0.004), irritability (beta = 0.282, p = 0.016), detachment (beta = 0.272, p = 0.017), psychasthenia (beta = 0.234, p = 0.031) and somatic anxiety (beta = 0.225, p = 0.046) were significant explanatory variables of reactivity to CPT. During MST, verbal aggression (beta = -0.252, 0.031) and detachment (beta = 0.253, p = 0.044) were significant predictors of norepinephrine and diastolic blood pressure response, respectively.Based on KSP-trait quartiles, delta (Delta) systolic (p = 0.025) and Delta diastolic blood pressure (p = 0.003) during MST were related to detachment score, with the highest reactivity in the 4th quartile, while Delta norepinephrine was significantly related to muscular tension (p = 0.033). Delta systolic and Delta diastolic blood pressure responses to CPT were dependent on detachment (p = 0.049 and p = 0.011, respectively) and psychasthenia (p = 0.020 and p = 0.015), while high verbal aggression was associated with lower reactivity measured by Delta norepinephrine (p = 0.037).

Conclusion: The present study indicates that stress reactivity is clearly related to different personality traits, without any single trait being dominant over others. Furthermore, personality seems to have as much, or even more, importance of predicting responses to CPT than responses to MST.