Papers of the Week

Despite growing interest in the role of stress mediators in pain chronicity, the effects of the stress hormone cortisol on acute pain remain incompletely understood. In a randomized, double-blind, placebo-controlled study with N=100 healthy volunteers, we tested the effects of oral hydrocortisone (20 mg) in two widely-used pain models for the visceral and somatic modality.Salivary cortisol was increased in the hydrocortisone group (time x group: p<.001). For the visceral modality, assessed using pressure-controlled rectal distensions, hydrocortisone decreased the pain threshold from pre- to post-treatment (time x group: p=.011), an effect primarily driven by women (time x sex: p=.027). For the somatic modality, cutaneous heat pain thresholds remained unaffected by hydrocortisone. Hydrocortisone did not alter perceived pain intensity or unpleasantness of either modality. Conditioned pain-related fear in response to predictive cues was only observed for the visceral modality (time x modality: p=.026), an effect that was significantly reduced by hydrocortisone compared ot placebo (time x group: p=.028).This is the first psychopharmacological study to support that acutely increased cortisol enhances pain sensitivity and impairs pain-related emotional learning within the visceral, but not the somatic pain modality. Stress-induced visceral hyperalgesia and deficits in emotional pain-related learning could play a role in the pathophysiology of chronic visceral pain.