[BEHAVIORAL, PHYSIOLOGICAL AND MORPHOLOGICAL CHARACTERISTICS ASSOCIATED WITH POST-TRAUMATIC RESPONSE TO CONTINUOUS EXPOSURE VERSUS ALTERNATE EXPOSURE IN AN ANIMAL MODEL OF POST-TRAUMATIC STRESS DISORDER].

Aims: The aim of this study was to approximate these conditions in an animal model of post-traumatic stress disorder (PTSD). More specifically, the neurobiological basis of these conditions, focusing on stress-related behavioral changes, HPA-axis and morphological were evaluated. The intention was to employ this well-validated, reproducible and reliable model for PTSD, to elicit data which will provide some guidance in the planning of a prospective study involving military personal.

Background: Combat personnel are exposed to significant stress and hardship, both physical and emotional, during their service and especially during active combat. Military forces are increasingly involved in conflicts involving nonmilitary or paramilitary adversaries in which they are exposed not to battles but to sporadic events, in what has come to be labeled "low intensity conflict". "Low intensity conflict" refers to a level of hostilities or use of military power that falls short of a full scale conventional or general war. These are characterized by brief periods of extreme stress and tangible danger interspersed by prolonged periods of siege. Whereas the potentially traumatizing effect of battle conditions is well documented, the risks of the sporadic highly stressful nature of "low intensity conflict" have not been studied. Furthermore, in recent years, soldiers commonly receive "relaxation periods" before re-engaging in battle. This new policy may possibly contradict the traditional treatment principles, focusing on "proximity" and "continuity" to the battlefield and its effects have not been studied.

Methods: Continuous and sporadic stresses, representing battlefield conditions, were induced in a validated rat animalmodel for PTSD and behavioral changes, hormonal levels and brain morphology were evaluated.

Results: Behavioral response, hormonal levels and brain morphological changes suggest that PTSD-like reactions were significantly higher in rats exposed to continuous stress compared to those exposed to intermittent stress and the control group.

Conclusions: The results support the assumption that "refreshing" during warfare may reduce the incidence of PTSD. Since this study is based on an animal model, its conclusions should also be validated in human observation studies.