Cerebellar responses during anticipation of noxious stimuli in subjects recovered from depression. Functional magnetic resonance imaging study.

BACKGROUND: Subjects recovered from depression have a substantial risk for recurrence of depression, suggesting persistent abnormalities in brain activity. AIMS: To test whether women recovered from depression show abnormal brain activity in functional magnetic resonance imaging (fMRI) during a conditioning paradigm with a noxious pain stimulus. METHOD: Ten unmedicated women who had recovered from major depression and eight healthy control women each received either noxious hot or non-noxious warm stimuli, the onset of which was signalled by a specific coloured light during 3-tesla echo planar imaging-based fMRI. RESULTS: Similar patterns of brain activation were found during painful stimulation for both patients and healthy controls. However, relative to healthy controls, subjects recovered from depression showed a reduced response in the cerebellum during anticipation of the noxious stimulus compared with anticipation of the non-noxious stimulus. CONCLUSIONS: Our data suggest that abnormal cerebellar function could be a marker of vulnerability to recurrent depression. This could provide a new target for therapeutic interventions.

High and low neuroticism predict different cortisol responses to the combined dexamethasone--CRH test.

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.

Modelling a loss event: effect of imagined bereavement on the hypothalamic-pituitary-adrenal axis.

BACKGROUND: Loss events are the stressors most closely associated with the onset of depressive illnesses. The acute cortisol response to loss has been little studied although it could be an important mediator of the effects of environmental stress on psychological state. METHODS: The salivary cortisol response to an established negative mood induction procedure involving music and an imagined bereavement was measured in 30 healthy volunteers. RESULTS: Considerable but transient mood lowering in response to the negative mood induction was associated with a small increase in cortisol output over 30 min. CONCLUSIONS: This procedure has some potential as a tool to investigate individual differences in the neuroendocrine response to loss events, but this is limited. There remains a need for laboratory models of relevant psychosocial stressors in mood disorders research.