Background: Overcommitment (OC) is a pattern of excessive striving. In reaction to work stress, OC has been associated with higher sympathetic nervous system activation and cortisol release, but data on neuroendocrine reactivity to standardized stressors are scarce. We investigated whether OC is associated with differential levels of the stress hormones norepinephrine and cortisol in response to acute psychosocial stress. Methods: Fifty-eight medication-free non-smoking men aged between 20 and 65 years (mean S.E.M.: 36.3 +/- 1.8) underwent an acute standardized psychosocial stress task combining public speaking and mental arithmetic in front of an audience. We assessed OC as well as a variety of psychological control variables including vital exhaustion, perfectionism, chronic stress, and cognitive stress appraisal. Moreover, we measured plasma norepinephrine as well as salivary cortisol before and after stress and several times up to 60 min thereafter. Results: Higher OC was associated with lower baseline norepinephrine levels (r = -0.37, p < 0.01). General linear models controlling for age, BMI, and mean arterial blood pressure revealed that higher overcommitment was associated with lower norepinephrine and cortisol levels before and after stress (p's < 0.02) as well as with lower norepinephrine stress reactivity (p = 0.02). Additional controlling for the potential psychological confounders vital exhaustion, perfectionism, chronic stress, and depression confirmed lower norepinephrine levels before and after stress (p < 0.01) as well lower norepinephrine stress reactivity (p = 0.02) with increasing OC. Higher OC independently explained 13% of the total norepinephrine stress response (beta = -0.46, p < 0.01, R-2 change = 0.13). Conclusions: Our findings suggest blunted increases in norepinephrine following stress with increasing OC potentially mirroring blunted stress reactivity of the sympathetic nervous system. (C) 2007 Elsevier Ltd. All rights reserved.
