What is Post-Traumatic Stress Disorder (PTSD)?

Janet Ryan-Newell, M.Ed.


As a psychologist, I have worked with thousands of clients across the mental health spectrum. Each client and each disorder are unique; however, some disorders are more deeply rooted and require more complex interventions than others.  Post-traumatic stress disorder (PTSD) is one such ailment. As a result, I have undertaken to write a multi-part series of posts to help counselling-adjacent professionals (e.g. personal injury lawyers, family physicians, social workers, etc.) and interested members of the public to develop a deeper understanding of what PTSD is, how it impacts a person, and what can be done to treat it.

What is Post-Traumatic Stress Disorder?

It is often useful to begin with data. According to the Canadian Psychologist Association (CPA, 2010), 9.2% of people develop post-traumatic stress disorder (PTSD) at least once in their lives. In Canada, PTSD is also diagnosed twice as often in females. Many of those diagnosed with PTSD developed it after assaultive violence (43.1%); others develop it after learning about another person’s trauma (34.5%). PTSD is also highly comorbid (i.e. linked) with major depression, substance abuse, and suicide. Given a prevalence of ~10% across Canada’s population, virtually everyone will have met someone who suffers from PTSD. This is precisely why it is important to understand what PTSD is and to come to appreciate its warning signs and indicators.

PTSD is a mental health condition that is triggered when a person experiences or witnesses a psychologically traumatic event.

An event is considered to be traumatic if the person experienced, witnessed, or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of self or others. The person’s response must have also involved intense fear, helplessness, or horror (American Psychiatric Association, 1994).

For diagnostic purposes, traumatic events are clearly differentiated from the very painful stressors that constitute the normal distresses of life such as divorce, serious illness, financial stress, and the like. These are instead characterized as adjustment disorders rather than stress disorders. PTSD has been conceptualized as a disorder of fear in which the individual has an exaggerated fear response or lacks the ability to control fear responses (Jovanovic & Ressler, 2010).  PTSD has also been described as a disorder of memory, in which individuals seem to “relive their trauma in the form of involuntary recollection” (McNally et al., 1998). In addition to demonstrating enhanced recall for traumatic memories, distressing recollections for those with PTSD are often “vivid” and “long-lasting” (Banich, 2009).

PTSD is the most commonly studied and probably the most frequently debilitating psychological disorder that occurs after traumatic events. It is also unique among psychiatric diagnoses because of the great importance placed upon the etiological agent (i.e. the cause or traumatic stressor). In fact, a practitioner cannot make a PTSD diagnosis unless the patient has actually met the “stressor criterion”, which means that he or she must have been exposed to an event that is considered traumatic (National Centre for PTSD, 2016). Historically, PTSD went by the names ‘shell shock’ in WWI and ‘combat fatigue’ in WWII; however, we have learned much about the disorder since that time.

PTSD is no longer linked explicitly to combat; instead, it can be a generalized response to any overwhelming traumatic event.  In fact, this cluster of symptoms is now understood to be a trauma response that could be triggered by any number of experiences that were intensely fearful or horrifying in which the person felt helpless, and which involved actual or threatened death or serious injury, or a threat to the physical integrity of self or others. Perhaps not surprisingly, traffic accidents have become recognized as the leading cause of post-traumatic stress disorder (PTSD) since the Vietnam war (Butler and Moffit, 1999; Turkal, 1999) It is estimated that 9 percent of survivors of serious accidents develop significant post-traumatic stress symptoms and that many other survivors have PTSD-like reactions. (Turkal, 1999).

It is the exposure to the traumatic event that facilitates the onset of persistent psychological symptoms. It is natural to feel afraid during and after a traumatic situation. Fear triggers many split-second physiological and emotional changes in the body to help defend against danger or avoid it. This ‘fight-or-flight’ response is a typical reaction meant to protect a person from harm. It is also natural to have some of these distress-related symptoms after a dangerous event. Sometimes people have very serious symptoms that go away after a few days or weeks. This is called acute stress disorder (ASD). Nearly everyone will experience a range of reactions after trauma, yet most people recover from the initial symptoms without requiring intervention.

Unfortunately, this isn’t the case with Post-Traumatic Stress Disorder. When the symptoms (1) last for longer than a month, (2) seriously affect one’s ability to function, and (3) the reactivity is triggered or exacerbated by the event itself, this could represent the emergence of PTSD. If these levels of reactive stress become entrenched, the disorder is categorically recognized as PTSD. To meet the criteria for diagnosis, symptoms must cause significant distress or impact functioning. When not addressed, symptoms worsen and may become unshakable. Therefore, early identification and intervention is critical. The American Psychological Association has clearly outlined the major symptoms of PTSD:

  • PTSD causes short-term memory loss and can have long-term chronic psychological repercussions.
  • PTSD is often accompanied by depression, intense guilt, or one or more anxiety disorders including severe generalized anxiety, tension, sleep issues, flashbacks, intrusive thoughts, and nightmares.
  • Emotional symptoms include dissociation and emotional numbness.
  • Anhedonia, characterized by a loss of interest in formerly enjoyable activities may also be present.
  • Physical symptoms among PTSD sufferers include higher rates of neurological, respiratory, musculoskeletal, and cardiovascular symptoms.

In summary, PTSD is often very debilitating individually; however, recognizing the symptoms of PTSD in yourself and in others can constitute an essential first step on the path to treatment. In my next post, I will consider the people who suffer from PTSD – how and why does PTSD emerge?

If you or someone you know thinks that they may be suffering from PTSD, please feel free to reach out to us for an assessment:


  1. American Psychiatric Association. (1994). Definition of a traumatic event in DSM and ICD classification systems. Retrieved from
  2. Banich, M. (2009). Executive Function. Current Directions In Psychological Science, 18(2), 89 94. doi: 10.1111/j.1467-8721.2009.01615.x
  3. Beck, J. and Coffey, S. (2007). Assessment and treatment of posttraumatic stress disorder after a motor vehicle collision: Empirical findings and clinical observations. Professional Psychology: Research and Practice, 38(6), pp.629-639.
  4. Butler, D. and Turkal, N. (1999). Post-traumatic Stress Reactions Following Motor Vehicle Accidents. Am Fam Physician., 60(2), pp.524-530.
  5. Canadian Psychological Association (CPA). (2010). Canadian Psychological Association > Simple Facts about Traumatic Stress and PTSD. Retrieved from
  6. Jovanovic, T., & Ressler, K. (2010). How the Neurocircuitry and Genetics of Fear Inhibition May Inform Our Understanding of PTSD. American Journal Of Psychiatry, 167(6), 648- 662. doi: 10.1176/appi.ajp.2009.09071074
  7. McNally, R., Metzger, L., Lasko, N., Clancy, S., & Pitman, R. (1998). Directed forgetting of trauma cues in adult survivors of childhood sexual abuse with and without posttraumatic stress disorder. Journal Of Abnormal Psychology, 107(4), 596-601. doi: 10.1037//0021-843x.107.4.596
  8. National Centre for PTSD. (2016). PTSD and DSM-V – PTSD. Retrieved from