Enhanced cortisol suppression to dexamethasone associated with Gulf War deployment

SummaryObjectiveTo examine whether PTSD or post-deployment health symptoms in veterans of the first Gulf War (Operation Desert Shield/Storm) are associated with enhanced suppression of the pituitary-adrenal axis to low-dose dexamethasone (DEX).MethodPlasma cortisol and lymphocyte glucocorticoid receptor (GR) number were measured at 08:00 h on two consecutive days, before and after administration of 0.5 mg of DEX at 23:00 h in 42 male Gulf War veterans (14 without psychiatric illness, 16 with PTSD only, and 12 with both PTSD and MDD) and 12 healthy male veterans not deployed to the Gulf War or another war zone.ResultsIn the absence of group differences in basal cortisol levels or GR number, Gulf War veterans without psychiatric illness and Gulf War veterans with PTSD only had significantly greater cortisol suppression to DEX than non-deployed veterans and Gulf War veterans with both PTSD and MDD. Gulf War deployment was associated with significantly greater cortisol suppression to DEX controlling for weight, smoking status, PTSD, and MDD; PTSD was not associated with response to DEX. Among Gulf War veterans musculoskeletal symptoms were significantly associated with cortisol suppression and those who reported taking anti-nerve gas pills (i.e., pyridostigmine bromide) during the war had significantly greater DEX-induced cortisol suppression than those who did not.ConclusionsThe data demonstrate that alterations in neuroendocrine function are associated with deployment to the Gulf War and post-deployment musculoskeletal symptoms, but not PTSD. Additional studies are needed to examine the relationship of enhanced glucocorticoid responsivity to deployment exposures and chronic unexplained medical symptoms in Gulf War veterans.