Acute stress reaction refers to the development of transient emotional, somatic, cognitive, or behavioural symptoms as a result of exposure to an event or situation (either short- or long-lasting) of an extremely threatening or horrific nature (e.g., natural or human-made disasters, combat, serious accidents, sexual violence, assault). Symptoms may include autonomic signs of anxiety (e.g., tachycardia, sweating, flushing), being in a daze, confusion, sadness, anxiety, anger, despair, overactivity, inactivity, social withdrawal, or stupor. The response to the stressor is considered to be normal given the severity of the stressor, and usually begins to subside within a few days after the event or following removal from the threatening situation.