High and low neuroticism predict different cortisol responses to the combined dexamethasone--CRH test.
McCleery JM., Goodwin GM.
BACKGROUND: Depression and posttraumatic stress disorder are both associated with altered function of the hypothalamic--pituitary--adrenal axis. Neuroticism is a strong predisposing factor for depression and probably also a risk factor for posttraumatic stress disorder. This study investigated whether young adults with high and low neuroticism scores show differences in hypothalamic-pituitary-adrenal axis regulation that might relate to their differential vulnerability to psychopathology. METHODS: Neuroticism was measured with the Eysenck Personality Questionnaire in 258 students aged 18--25. Fourteen scoring in each of the upper and lower quartiles of the neuroticism distribution according to gender participated in a combined dexamethasone-corticotropin-releasing hormone test. RESULTS: Low-neuroticism individuals showed a significantly greater cortisol response than high-neuroticism individuals. CONCLUSIONS: The mechanism of this effect remains to be elucidated. High-neuroticism subjects may have a downregulated hypothalamic--pituitary--adrenal axis to prevent harmful overactivation. This is the first demonstration of a difference in hypothalamic--pituitary--adrenal axis regulation associated with neuroticism.