<P> A recent study found that a single stressful event may cause long - term consequences in the brain . This result calls the traditional distinction between the effects of acute vs chronic stress into question . </P> <P> Stress is characterized by specific physiological responses to aversive or noxious stimuli . </P> <P> Hans Selye was the first to coin the term "general adaptation syndrome", to suggest that stress induced physiological responses proceed through the stages of alarm, resistance, and exhaustion . </P> <P> The sympathetic branch of the autonomic nervous system gives rise to a specific set of physiological responses in response to physical or psychological stress . The body's response to stress is also termed "fight - or - flight response", and it is characterized by an increase in blood flow to skeletal muscles, the heart and brain, a rise in heart rate and blood pressure, as well as dilation of pupils, and an increase in the amount of glucose released by the liver . </P>

When was acute stress disorder as a result of combat recognized