Post-traumatic stress disorder (PTSD)

Post-traumatic stress is a reaction some people have after experiencing, witnessing or hearing about any type of deeply distressing event.

On this page, you can find the following information:

Key points about post-traumatic stress and PTSD

  1. Traumatic events can involve actual or threatened death, serious injury,  sexual violence or emotional abuse.
  2. A trauma is defined as an emotional response to a shocking, stressful or dangerous event that you see or experience or hear about, especially if it happened to someone close to you.
  3. After experiencing or learning about deeply distressing events, post-traumatic stress reactions are normal. These may include difficulty relaxing, nightmares or flashbacks, numbness, changes in mood or appetite, diminished ability to concentrate or socialise, and avoiding anything related to what happened.
  4. Post-traumatic stress disorder (PTSD) is diagnosed if your post-traumatic symptoms last longer than a month and cause you significant difficulties in your everyday functioning.
  5. Not everyone who experiences trauma develops PTSD. It is not a sign of weakness and post-traumatic stress and PTSD can happen to anyone. In many ways, it is a normal part of the traumatic healing process.
  6. PTSD can be triggered by a single traumatic event, several traumatic events at different times or ongoing traumatic circumstance (see also complex-PTSD).
  7. There is help available and most people recover or their symptoms become mild.

What causes post-traumatic stress and PTSD? 

No one is completely sure why post-traumatic stress develops. Some theories say it could be your brain's way of trying to keep you better prepared next time something happens. Re-experiencing an event with flashbacks may be your mind’s way of trying to make sense of an overwhelming and scary experience.

PTSD can be triggered by a single traumatic event (eg, an earthquake, assault or car crash) or several traumatic events at different times. If you experience ongoing traumatic circumstances especially during childhood (eg, childhood abuse or neglect), you may also develop a condition known as complex-PTSD or C-PTSD. Read more about C-PTSD.

What are the symptoms of post-traumatic stress?

The symptoms of post-traumatic stress are a part of a normal response to a traumatic experience. They are not a sign of weakness or inability to cope. Over time these feeling usually settle but if not they can cause ongoing distress. 

Symptoms may include: 

  • being wired and on edge, watchful or jumpy
  • disturbed sleep with nightmares
  • avoiding situations, people or events that remind you of the event
  • flashbacks of images, memories and thoughts about the event
  • feeling numb and withdrawn or spacey and not present
  • difficulty with memory, concentration and decision-making
  • body symptoms, such as digestive problems, headaches or other non-specific pain
  • changes in appetite (lack of appetite or overeating)
  • increase in the use substances (alcohol, cigarettes, or drugs)
  • changes in mood (tearfulness, irritability, anger, guilt)
  • sense of helplessness and hopelessness.

In children, look out for agitated or changed behaviour, nightmares, repetitive play about the event or unexplained physical symptoms.

When should I see my doctor?

It is normal to feel shocked and upset after a traumatic event/s, but if you have disturbing thoughts and feelings for more than a month that you experience as severe, or if you feel you're having trouble getting your life back under control, talk to your doctor or a mental health professional.

Getting treatment as soon as possible can help prevent post-traumatic symptoms from getting worse and developing into PTSD.

How is post-traumatic stress disorder diagnosed?

To be diagnosed with PTSD, your doctor will ask questions to see if you meet the criteria set out in the most recent version of the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5). 

There are 8 criteria: 

  1. Exposure to actual or threatened death, serious injury or sexual violence.
  2. The presence of one or more intrusion symptoms associated with the traumatic event, such as flashbacks and distressing dreams.
  3. Ongoing avoidance of anything that makes you recall the event or external reminders, such as people of places.
  4. Negative changes in your thinking and mood, such as believing there is something wrong with yourself or feeling fear, horror, anger, guilt, or shame.
  5. Noticeable changes in your behaviours, such as how angry or reckless you are, or how well you sleep.
  6. All of these changes have lasted for more than 1 month.
  7. The changes are causing you significant distress or impairment in your social or work life or other important areas of functioning.
  8. The changes aren’t caused by use of a substance, eg, alcohol or medicine or another medical condition.

You can read the full criteria in medical terminology.

How is post-traumatic stress disorder treated?

Talking therapy with someone experienced in working with PTSD and who you feel safe with and trust is the best way to recover. Medicine for anxiety or depression, in combination with talking therapies may also help you to manage your symptoms, but won’t heal the PTSD.

When to get emergency help

If you think you may hurt yourself or attempt suicide, call 111 or your local emergency number immediately. If you know someone who is in danger of attempting suicide or has made a suicide attempt, make sure someone stays with that person to keep them safe. Call 111 or your local emergency number immediately. Or, if you can do so safely, take the person to the nearest hospital emergency room.

What can I do to look after myself if I have post-traumatic stress?       

  • Take good care of your basic needs, such as sleep, exercise, healthy eating and quiet time.
  • Tell your friends and family/whānau – they can support you.
  • Some people feel that they benefit from writing about or drawing what happened, while others heal better by letting these memories fade for a while.  
  • Do things that help you feel calm, such as taking a walk or a bath, reading a good book or listening to soothing music.
  • Read about a PTSD app you can download onto your phone. 

Where can I find support?

There may be a support group in your area for people who have had a similar experience. Ask your doctor or therapist. If you need someone to talk to urgently, contact:

  • 1737 – free text or call any time of day or night to speak to a trained counsellor 
  • Lifeline 0800 543 354
  • Healthline 0800 611 116
  • Samaritans 0800 726 666
  • Youthline 0800 376 633

Learn more

Post-traumatic stress disorder Mental Health Foundation, NZ
Post-traumatic stress disorder (PTSD) Better Health Channel, Australia
PTSD Royal Australian and NZ College of Psychiatrists
Find out how to tell if someone is struggling with their mental health BBC, UK, 2021
I can't get over it Books On Prescription, NZ
Self-help guide – post-traumatic stress Moodjuice
PTSD questionnaire Anxiety and Depression Association of America
PTSD symptoms, self-help, and treatment
Experiential exercises Peter Levine, US

Ministry of Health resources


  1. Iribarren J, Prolo P, Neagos N, Chiappelli F. Post-traumatic stress disorder – evidence-based research for the third millennium.  Evid Based Complement Alternat Med. 2005 Dec; 2(4): 503–512.
  2. Post-traumatic stress disorder Patient Info, UK
  3. DSM-5 PTSD diagnostic criteria – what's changed from DSM-IV? Very Well Mind, US, 2019
  4. Post-traumatic stress disorder Harvard Health Publishing, US, 2020
  5. DSM-5 diagnostic criteria for PTSD National Center for Biotechnology Information, US

Reviewed by

Dr Dr Adrienna Ember is a clinical psychologist, coexisting disorders therapist, and personal development strategist in private practice. She supports people with diverse sexual orientations and cultural backgrounds. Adrienna also provides supervision and therapy for those with high public exposure/stressful work conditions (eg, medical professionals, CEOs, lawyers, politicians, police, artists) to avoid burnout and maintain safe practice.
Credits: Health Navigator Editorial Team. Reviewed By: Dr Dr Adrienna Ember, Clinical Psychologist, Waikato Last reviewed: 21 Apr 2021