That route of signalling increases the rate of noradrenergic activity in the locus ceruleus, and the person becomes more alert and attentive to their environment.If a stimulus is perceived as a threat, a more intense and prolonged discharge of the locus ceruleus activates the sympathetic division of the autonomic nervous system. The activation of the sympathetic nervous system leads to the release of norepinephrine from nerve endings acting on the heart, blood vessels, respiratory centres, and other sites. The ensuing physiological changes constitute a major part of the acute stress response. The other major player in the acute stress response is the hypothalamic-pituitary-adrenal axis. Stress activates this axis and produces neuro-biological changes. These chemical changes increase the chances of survival by bringing the physiological system back to homeostasis.The autonomic nervous system controls all automatic functions in the body and contains two subsections within it that aid the response to an acute stress reaction. These two subunits are the sympathetic nervous system and the parasympathetic nervous system. The sympathetic response is colloquially known as the "fight or flight" response, indicated by accelerated pulse and respiration rates, pupil dilation, and a general feeling of anxiety and hyper-awareness. This is caused by the release of epinephrine and norepinephrine from the adrenal glands. The epinephrine and norepinephrine strike the beta receptors of the heart, which feeds the hearts sympathetic nerve fibres to increase the strength of heart muscle contraction; as a result, more blood gets circulated, increasing the heart rate and respiratory rate.
It was assumed to be a temporary response of healthy individuals to witnessing or experiencing traumatic events. Symptoms include depression, anxiety, withdrawal, confusion, paranoia, and sympathetic hyperactivity.The APA officially included the term ASD in the DSM-IV in 1994. Before that, symptomatic individuals within the first month of trauma were diagnosed with adjustment disorder. According to the DSM-IV, acute stress reaction refers to the symptoms experienced immediately to 48 hours after exposure to a traumatic event. In contrast, acute stress disorder is defined by symptoms experienced 48 hours to one month following the event. Symptoms experienced for longer than one month are consistent with a diagnosis of PTSD.Initially, being able to describe different ASRs was one of the goals of introducing ASD. Some criticisms surrounding ASDs focal point include issues with ASD recognising other distressing emotional reactions, like depression and shame. Emotional reactions similar to these may then be diagnosed as adjustment disorder under the current system of trying to diagnose ASD.Since its addition to the DSM-IV, questions about the efficacy and purpose of the ASD diagnosis have been raised. The diagnosis of ASD was criticized as an unnecessary addition to the progress of diagnosing PTSD, as some considered it more akin to a sign of PTSD than an independent issue requiring diagnosis. Also, the terms ASD and ASR have been criticized for not fully covering the range of stress reactions. == References ==