COVID-19:  Screening, updates and safety protocols: 

Acute Stress Disorder

Individuals may develop an anxiety disorder called Acute Stress Disorder (ASD) following a traumatic event. ASD typically occurs within one month after the traumatic event occurs. It lasts at least three days and can persist for up to one month. People with ASD have symptoms similar to those seen in post-traumatic stress disorder (PTSD).

What Causes Acute Stress Disorder?

Experiencing, witnessing, or being confronted with one or more traumatic events can cause ASD. The events create intense fear, horror, or helplessness.

Traumatic events that can cause ASD include:

  • Death;
  • A threat of death to oneself or others;
  • A threat of serious injury to oneself or others;
  • A threat to the physical integrity of oneself or others.

Who Is at Risk for Acute Stress Disorder?

Anyone can develop ASD after a traumatic event. There is an increased risk of developing ASD if you have:

  • Experienced, witnessed, or been confronted with a traumatic event in the past;
  • A history of ASD or PTSD;
  • A history of certain types of mental problems;
  • A history of dissociative symptoms during traumatic events.

What Are the Symptoms of Acute Stress Disorder?

The symptoms of ASD include:

    Negative Mood

    • Persistant inability to experience positive emotions (i.e. unable to feel happy or satisfied)

      Dissociative Symptoms

      • Feeling numb, detached, or being emotionally unresponsive;
      • A reduced awareness of your surroundings;
      • De-realization, which occurs when your environment seems strange or unreal to you;
      • Depersonalization, which occurs when your thoughts or emotions don’t seem real or don’t seem like they belong to you;
      • Dissociative amnesia, which occurs when you cannot remember one or more important aspects of the traumatic event

      Re-experiencing the Traumatic Event

      • Having recurring images, thoughts, nightmares, illusions, or flashback episodes of the traumatic event;
      • Feeling like you’re re-living the traumatic event;
      • Feeling distressed when something reminds you of the traumatic event.


      You may avoid stimuli that cause you to remember or re-experience the traumatic event, such as:

      • People;
      • Conversations;
      • Places;
      • Objects;
      • Activities;
      • Thoughts;
      • Feelings.

      Anxiety or Increased Arousal

      The symptoms of ASD may include anxiety and increased arousal. The symptoms of anxiety and increased arousal include:

      • Having trouble sleeping;
      • Being irritable;
      • Having difficulty concentrating;
      • Being unable to stop moving or sit still;
      • Being constantly tense or on guard;
      • Becoming startled too easily or at inappropriate times.


      The symptoms of ASD may cause you distress or disrupt important aspects of your life, such as your social or work settings. You may have an inability to start or complete necessary tasks or an inability to tell others about the traumatic event.


      A combination of medication and psychiatric education may be used to reduce symptoms from the disorder. Cognitive behavioural therapy may be offered to increase recovery speed and prevent ASD from turning into PTSD. Individuals may also be treated with exposure-based therapies and/or hypnotherapy.

      Accessing Care for Traumatic Stress

      What Is the Long-Term Outlook?

      Many people with ASD are later diagnosed with PTSD. A diagnosis of PTSD is made if your symptoms persist for more than a month and cause a significant amount of stress and difficulty functioning.

      Treatment may reduce your chances of developing PTSD.


      Can I Prevent ASD?

      Because there’s no way to ensure that you never experience a traumatic situation, there’s no way to prevent ASD. However, there are things that can be done to reduce your likelihood of developing ASD.

      Getting medical treatment within a few hours of experiencing a traumatic event may reduce the likelihood that you’ll develop ASD. People who work in jobs that carry a high risk for traumatic events, such as military personnel, may benefit from preparation training and counselling to reducing their risk of developing ASD or PTSD if a traumatic event does occur.

      Preparation training and counselling may involve fake enactments of traumatic events and counselling to strengthen coping mechanisms.

      The Mental Health First Aid Program offered at Ontario Shores is a good way to improve mental health knowledge and understanding and may help prepare them for a traumatic event by training individuals how to respond to a mental health crisis.

      * Adapted from various internet sources including WebMD, PsychCentral and CMHA

      Was this page helpful?

      If you would like us to follow-up with you to provide assistance, please enter your preferences for how you wish to be contacted below: