[Biological basis of posttraumatic stress disorder].

The postraumatic psychobiological stress disorder (PTSD) remains unclear although it is suggested that many systems are implicated. In this article, the PTSD biological aspects are reviewed, providing an exposition of main changes which are taking place in both the hypothalamic pituitary adrenal (HPA) and sympathetic nervous system (SNS). There are also some other mechanisms which are involved into human stress response such as thyroid function, neuropeptide Y, substance P and the opiod and glutamatergic system. Finally, we remark some changes which were found in neuroimaging techniques.