Studies on pathophysiology of PTSD using the SPS model

Animal models are important tools for the study of pathophysiology and the developmentof new treatments for mental disorders. A number of animal models of posttraumaticstress disorder (PTSD) have been proposed, and these can be categorizedinto two major groups according to their basic concepts. One idea of model constructionis that stress given to animals should simulate traumatic events in humans.The researchers utilize social stress which is more naturalistic than electric shocksor restraint (Koolhaas et al. 1997). For example, animals are exposed to a predatoror predator odor and the alterations induced by the stress exposure are analyzed.Pathophysiological consequences of predator stress are described by Adamec inChap. 5.In the other animal models of PTSD, researchers focus on the alterations inducedby stress resembling symptoms of PTSD, although the stress paradigm itself is completelyartificial. As was reviewed by Foa et al. (1992), animals exposed to uncontrollableand unpredictable stress showed similar disturbances to those found in PTSD. Because pathogenesis of mental disorders is still unclear, most animal modelsare based on similarities in neurochemical, neurophysiological, or behavioralmanifestations between model animals and clinical observations. However, "facevalidity" is only the first step in establishing a model (Yehuda and Antelman 1993).Therefore, although animal research simplifies the investigation of possible pathophysiologyand molecular mechanisms of human diseases, confirmation in clinicalresearch is needed.