POMC and dysautonomia: In Gulf War veterans, alterations in the HPA axis (specifically suppression of adrenocorticotropic hormone (ACTH) and cortisol) has been linked to environmental exposures, including chemical warfare agents, pesticides, and other environmental stressors, possibly contributing to long-term GWI symptoms such as disabling fatigue, post-exertional malaise, dysautonomia, sleep disturbances, and cognitive impairments [106].