Neurobiology of posttraumatic stress disorder.

Recent advances on the neurobiology of posttraumatic stress disorder include: the utilization of functional brain imaging; the incorporation of cross-system research including neuroendocrine (hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes), neurochemical (corticotropin-releasing factor, norepinephrine, serotonin, endogenous opiates), and neuroimmunological (humoral and cellular immunity) systems; the expansion beyond exclusive study of combat veterans to include posttraumatic stress disorder patients suffering from noncombat traumas; and the development of animal models of traumatic stress.