Acute stress disorder is a short-term anxiety disorder triggered by a traumatic, life-threatening event that causes a reaction of fear, helplessness, or horror.

Symptoms include feeling numb, reliving the event through disturbing memories or dreams, and avoiding anything that may be a reminder of the event. Symptoms are so intense that they disrupt daily activities like going to work and interacting with other people. After the event, the symptoms must last for at least 2 days but can last up to 4 weeks. Symptoms that last longer than 1 month are called post-traumatic stress disorder.