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Completed Research Projects
Title: Glucocorticoid Responsivity in Gulf War Veterans
Synopsis: This project reviewed the potential relationship between Gulf War illness and PTSD.
Overall Summary: This is a proposal for a multidimentional study, combining FDG-PET (fluorodeoxyglucose and Positron Emission Tomography) neuroimaging, neuropsychiatric evaluation and glucocorticoid challenge tests to examine the glucocorticoid responsiveness in Gulf War Veterans (GWV). The PI is currently utilizing this approach to investigate the effects of glucocorticoids on regional brain glucose metabolism (rGMR) and memory performance in Vietnam and older combat veterans. However, preliminary findings from a separate ongoing project, demonstrating qualitatively different neuroendocrine aleterations in GWV than in Vietnam veterans, lead us to suspect that glucocorticoids exert different effects on both rGMR and memory performance in GWV. In GWV, neuroendocrine alterations appear to be associated with symptoms of Gulf War Illness (GWI) independent from, and in a different direction than, their associations with PTSD, raising the possibility that GWI and PTSD act synergistically (either by enhancing each other's effects or inhibiting them). Moreover, pilot data on 5 GWV with PTSD show differences in baseline attention. We use a multidimensional approach to measure the effects of glucocorticoids on neuroendorcine, neuroanatomic and behavioral domains because the illnesses we wish to characterize are complex and multifaceted, and will likely not be as clearly understood if studied using only a single modality.
Overall Project Objective: To provide important information regarding interactions among neuroendocrine, neuroanatomic, and behavioral responses to glucocorticoids, our design will definitely address the question of the relationship between GWI and PTSD.
Results to Date: None to date.
Project: VA-129
Agency: Department Of Veterans Affairs
Location: VAMC Bronx
P.I. Name: Rachel Yehuda
Status: Complete
Study Start Date: October 01, 2004
Estimated Completion Date: September 30, 2007
Specific Aims: While our methodology will provide important information regarding interactions among neuroendocrine, neuroanatomic, and behavioral responses to glucocorticoids, our design will definitely address the question of the relationship between GWI and PTSD. The growing literature on GWV provides ample evidence that PTSD and GWI often co-occur, but has not yet clarified whether GWI and PTSD represent different aspects of a more unitary syndrome associated with deployment to the Gulf, or two distinct problems, that interact. This essential question must be addressed if we are to formulate appropriate treatment for GWV.
Methodology: Verbal memory and working memory than to Vietnam veterans with PTSD, and demonstrate directionally different patterns of both rGMR and performance on these tasks in response to hydrocortisone administration. For this reason, we proposed a 2 x 2 design (PTSD+, PTSD-and GWI+, GWI-) in which the functional meuroanatomy of glucocorticoid responsiveness, and its relationship to cognitive performance, will be evaluated in four groups (PTSD+GWI, PTSD-GWI+, PTSD-GWI+, PTSD-GWI-), each comprised of 16 trauma-exposed GWV. Two neuroendocrine challenges will be performed to assess glucocorticoid responsiveness: a double-blind placebo-controlled (17.5mg) hydrocortisone challenge test during which adrenocorticotropin hormone (ACTH) suppression, rGMR, and memory performance indices will be assessed, and the low dose (0.50mg) dexamethasone suppression test (DST). rGMR of several regions of interest including the hippocampus, amygdala, and anterior cingulated, will be determined after anatomical localization of FDG-uptake by co-registration of MRI images. We focus on glucocorticoid responsiveness because the hypothalamic-pituitary-adrenal (HPA) axis plays a role in mood and PTSD; it coordinates many aspects relating to physical and somatic illness, and has demonstrable effects on memory.
Publications:
No Publications at this time...
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