PTSD: defined

Post-traumatic stress disorder (PTSD) is a psychiatric condition that is diagnosed clinically, that is, by sitting down with a professional and giving a thorough account of what you are experiencing. Although the diagnostic criteria in the DSM (Diagnostic and Statistics Manual of Mental Disorders) is more detailed, the spirit of the disorder is marked by the presence of the following:

Hyperarousal. E.g., a war veteran hears a traffic helicopter and starts to panic. Common symptoms of hyperarousal include Irritability, recklessness, hypervigilance, an exaggerated startle response, problems in concentration, sleep issue, etc.

Avoidance. E.g., a patient who had been in a car accident doesn’t want to get back in the car or doesn’t want to see anything that is reminding of the accident; or, internally, patients can just detach themselves from social groups and numb their feelings in an attempt to be ‘impervious’ to it all.

Re-experiencing. This refers to the intrusive uncomfortable thoughts, emotions and physical sensations that are consequent to the trauma. They can take the form of:

  • Flashbacks or a dissociative reaction where one sort of blanks out and involuntarily disconnects one’s attention from what is going on;
  • Nightmares;
  • Emotions that tally with the emotions of the trauma;
  • Sensory perceptions that tally with those experienced in the trauma (e.g., a lighting pattern, a sound, etc.). These can be frustrating as people can develop seemingly ‘strange’ associations that don’t seem immediately logical, e.g., a route into work may expose one to a pattern of light that flickers through the trees in a pattern that tallies with sensations one experienced at the time of the trauma leading to symptoms of hyperarousal;
  • Memories (recurrent, involuntary and intrusive);
  • Intense and prolonged reaction after an exposure to direct or indirect reminder to a trauma.

Mood. Negative changes in cognition and mood like…

  • Inability to recall key features of traumatic events;
  • Persistent – and often distorted – negative beliefs and expectations about oneself or the world, e.g., “it’s all my fault”, “the world is a dangerous place”;
  • Feeling alienated;
  • Decreased interest in things you used to enjoy;
  • An affect that is flatter, like you were wearing a mask;
  • Depersonalization – feeling like you’re not your self;
  • Derealization – feeling like the world is not normal;
  • Feeling ashamed;
  • Feeling guilty.

PTSD only occurs if people process the event or its consequences in a way that makes them feel like they are still under threat. Some patients can have beliefs or values that makes it more likely to appraise an event in a negative light, or more negatively than others. Some people may have a different recollection of how things went down; we all see the world through a lens that takes the shade of things we either liked or disliked in our past.

Unlike anxiety in which people fear the unknown, in PTSD, patients fear something that already happened. In other words, patients are afraid of their memories, and they are acting as if they are back there, although they may be in a safe place like in the comfort of their living rooms. Sometimes patients are not consciously aware of the link between their symptoms and their triggers. That is, the “reminders” that trigger PTSD symptoms may correlate with inconspicuous factors in the trauma that weren’t previously consciously processed. What’s more, not identifying or processing these “reminders”, may even be a feature of PTSD, i.e., shutting out memories, avoidance of what hurts, kind of like the illness (i.e., PTSD) is protecting itself.

Situations that trigger PTSD symptoms can be subtle. They can include:

  • A single event or a series of events – like someone close to you going through something that kindles your fear structure (see below).
  • Thoughts, images, memories, flashbacks – these are often intrusive, which is part of the paradox of PTSD. While these have to be processed in treating PTSD, PTSD sufferers often avoid doing the same, either intentionally or unintentionally, and what happens? These thoughts have a way of worming their way in. Try the little experiment dealing with Ironic Process Theory in the paragraph on “Avoidance” in the section “What are common things patients do that might unintentionally perpetuate PTSD?”.
  • Emotions – this can be very frustrating as it is hard to avoid an emotion. This frustration is an added burden; it is labelled as a secondary emotion as it is “baggage” that was “added on” after the trauma in the PTSD journey. See the paragraph on “Secondary Emotions” in the section “What are common things patients do that might unintentionally perpetuate PTSD?”.
  • Behaviour – this can be something as mundane as going to get the mail if somehow it jogs the PTSD-fight-or-flight reflex. Perhaps, there is some detail that relates back the the trauma?
  • Physiological sensations – this can be something as nonspecific as neck tension, butterflies in the stomach, palpitations, etc. Nonspecific refers to the fact that these symptoms can happen in contexts that have nothing to do with the trauma, like neck tension can happen from sitting at a desk with awkward posture for too long.


Fear Structure

PTSD occurs because of the development of a disempowering fear structure. At the time of the trauma, say a car accident, one may have sensed honking, lights flashing, sirens, ambulances, broken glass, airbags, a song that was playing on the radio, a black BMW, and so on. One may have thought “I’m going to die”. The fear structure may connect this feeling of “I’m going to die” with all of those other things that were sensed at the time of the car accident, even if none of them, in and of themselves, poses any threat to life (e.g., song on the radio, loud sounds, etc.). Basically, these fears get taken out of context and generalized to many other aspects of life. These associations are not helpful to living life in a desired manner. This fear structure provides the fuel for developing the avoidance strategies that so many PTSD patients adopt; strategies that further perpetuate the disorder (see below “Common things patients do that worsens their lot: Avoidance and Secondary Emotions”).


Poor Integration into Autobiographical Context (Memory)

This sounds like a fancy title but it just means that the trauma doesn’t seem to fit with a patient’s perceived sense of self. So it is seen as a stain they carry around rather than becoming integrated in the background pattern (i.e., their sense of self) – vzv. coming to terms with it and processing it. That us, until the trauma is adequately processed, the trauma doesn’t seem to make sense. Perhaps it’s the timing, or the place of the trauma, or how you saw yourself before, or how you see yourself after the trauma is at odds with “allowing” that this trauma happened and you can move on. This leaves the patient in the hear-and-now, experiencing all the unwanted symptoms described above. A disorganized, or unclear sense of self, will make it even more likely that triggers will occur. If a patient dissociates – that is, experiences a sense of detachment from reality – it will make it even more unlikely that the autobiographical memory (i.e., having your “story” clear in the back of your mind) can be worked on. This, again, is like an auto-protect feature the illness (i.e., PTSD) uses to keep surviving. Dissociation can involve zoning out or one can outright forget what happened for a period of time. One patient we had walked back to her car and found that she had a flat tire. The stress was too overwhelming that the next thing she could remember was that she was back at home 2 hours later. Her husband had to fill her in on the details.

One of the most telling beliefs that predicts increased PTSD symptoms is that they believe that they have been fundamentally changed and that they will never be the same again. This can lead to the frozen-in-time syndrome in which many PTSD patients find themselves: unable to resume former life or start anew.

A traumatic event has to contain real or threatened emotional and/or physical harm/danger. In some instances, the patient can suffer from PTSD on just hearing about the trauma if it affects them intimately, e.g., hearing about a trauma that occurred to a child can trigger PTSD in a parent. Some people have latent (i.e., not clinically manifest) trauma lingering from the past, even from as far back as when they were pre-verbal (i.e., before the age of 2), pre-concussion, etc. And, although these traumas never developed into clinical PTSD, they can set the stage for being more susceptible to PTSD. Those traumas may have been influential in setting up our fear structure (see “Why does PTSD happen?”) or core beliefs about ourselves. In this context, a subsequent trauma may hit a sore spot leading to a negative appraisal of the event: “I shouldn’t have put myself in that situation in the first place”, “The world is a dangerous place”, etc. As such, it should be noted that an event that causes PTSD in one patient may not do so in another. In fact, fortunately, most traumatic events experienced by people do not lead to PTSD.

An analysis from a survey of a large, representative community-based sample in 24 countries estimated the chance of developing of PTSD based on the type of trauma one faces (Kessler et al., 2014):

  • Sexual relationship violence – 33 percent (e.g., rape, childhood sexual abuse, intimate partner violence).
  • Interpersonal-network traumatic experiences – 30 percent (e.g., unexpected death of a loved one, life-threatening illness of a child, other traumatic event of a loved one).
  • Interpersonal violence – 12 percent (e.g., childhood physical abuse or witnessing interpersonal violence, physical assault, or being threatened by violence).
  • Exposure to organized violence – 3 percent (e.g., refugee, kidnapped, civilian in war zone).
  • Participation in organized violence – 11 percent (e.g., combat exposure, witnessing death/serious injury or discovered dead bodies, accidentally or purposefully caused death or serious injury).
  • Other life-threatening traumatic events – 12 percent (e.g., life-threatening motor vehicle collision, natural disaster, toxic chemical exposure).

The chance of getting PTSD in a lifetime ranges from 6.1 to 9.2 percent in national samples of the general adult population in the United States and Canada (Kessler et al., 2005; Van Ameringen et al., 2008; Koenen et al., 2017; Goldstein et al., 2016). Any given year, about 3.5 to 4.7 percent have PTSD (Goldstein et al., 2016; Kessler et al., 2005).

Interestingly, lower prevalence rates have been found outside of North America. While we’re not sure why people outside North America have a lower rate of developing PTSD, we know that the likelihood of developing PTSD is affected by a number of factors (Stein et al., 2000; kroll et al., 2003; Sareen et al., 2013).

Prospective studies indicate that PTSD symptoms are almost universal in the immediate aftermath of trauma (Rothbaum et al., 1992). The majority of individuals have symptoms of re-experiencing, avoidance, and hyperarousal following a severely traumatic event. For most individuals, these symptoms steadily resolve over time, while those who meet diagnostic criteria for PTSD continue to experience the symptoms. PTSD can thus be viewed as a failure of recovery caused in part by a failure of the fear phasing out (Rothbaum et al., 2003).

Emotional processing theory holds that PTSD emerges due to the development of a fear network in memory that elicits escape and avoidance behavior. Exposure therapy assists patients in confronting their feared memories and situations in a therapeutic manner. Re-experiencing the trauma through exposure allows it to be emotionally processed so that it can become less painful (Foa et al., 1986, 1989).

Another misunderstanding is that the further you get away from the trauma, the less likely you are to get PTSD. Technically, one will not be said to have PTSD unless the symptoms last for longer than a month out from the trauma. However, people can continue to develop PTSD even years after the trauma. Delayed onset of PTSD can occur when something that happens after the trauma gives the trauma a more threatening meaning. Most individuals who develop PTSD experience its onset within a few months of the traumatic event. However, epidemiological studies have found that approximately 25 percent experience a delayed onset after six months or more (Smid et al., 2009).

Risk factors for developing PTSD include being female; younger age at trauma; lower education; lower socioeconomic status; being separated, divorced, or widowed; previous trauma; general childhood adversity; personal and family psychiatric history; reported childhood abuse; poor social support; and initial severity of reaction to the traumatic event (Van Ameringen et al., 2008; Vieweg et al., 2006 ; Liebschutz et al., 2007; Bisson et al., 2015; Brewin et al., 2000).

The percentage of people that go on to develop PTSD after a traumatic event is influenced by the patient’s characteristics and the details surrounding the inciting event (Yehuda et al., 2015). Women are four times more likely to develop PTSD than men, after adjusting for exposure to traumatic events (Vieweg et al., 2005). The rates of PTSD are similar among men and women after events such as accidents (6.3 versus 8.8 percent), natural disasters (3.7 versus 5.4 percent), and sudden death of a loved one (12.6 versus 16.2 percent). Traumatic brain injury (TBI) and PTSD have high rates of co-occurrence among civilians and, particularly, among soldiers with combat-related TBI (O’Donovan et al., 2014). As an example, 11 percent of American soldiers returning from combat in Iraq and Afghanistan were reported to screen positive for PTSD in 2008.

  1. Suicide. As with any mental health disorder, suicide remains a significant concern..
  2. Chronicity. PTSD is commonly a chronic condition, with only one-third of patients recovering at one-year follow-up and one-third still symptomatic ten years after the exposure to the trauma (Kessler et al., 1996)
  3. Co-occuring mental health conditions. Disability can endure for a long period of time and one can develop other overlapping mental health issues. The National Comorbidity Survey data suggest that 16 percent of PTSD patients have one coexisting psychiatric disorder, 17 percent have two psychiatric disorders, and 50 percent have three or more (Kessler et al., 1996). Depressive disorders, anxiety disorders, and substance abuse are two to four times more prevalent in patients with PTSD; substance abuse is often due to the patient’s attempts to self-medicate symptoms (Kessler et al., 1996). Approximately 20 percent of people with PTSD have reported use of alcohol or other substances to reduce tension (Leeies et al., 2010).
  4. Co-occuring “physical” health conditions. Research evidence suggests that exposure to traumatic events and PTSD are associated with a range of physical health conditions including Bone and joint, neurological, cardiovascular, respiratory, autoimmune and metabolic disease.


Avoidance strategies are commonly employed by those with PTSD in an attempt to not re-experience the discomfort of the trauma. Avoidance strategies can be subdivided into 2 categories:

  1. Internal: avoiding thoughts and emotions that remind you of the trauma.
  2. External: avoiding any external thing that may remind you of the trauma.

Another way to look at it is whenever anything distressing happens, we tend to have strategies to deal with it; these are known as coping skills. Some of us have more effective coping skills than others. Avoidance is a “coping skill” that often develops in the context of PTSD, but it’s not helpful. Paradoxically, these strategies bring on more opportunities for re-experiencing the trauma and in a negative context: one rooted in fear.

The reason comes from Ironic Process Theory which states deliberate attempts to suppress certain thoughts make them more likely to surface. Try this experiment, for the next minute don’t think about a blue gorilla, think about anything you like but a blue gorilla…How long did you hold out for?


How Avoidance Strategies look

Avoidance strategies can take many forms. People will adopt a unique variety of avoidance strategies but some are common. For example, getting high can prevent someone from processing the memory. While processing the memory is uncomfortable, it a step in the right direction to breaking the cycle of avoidance and intrusive thoughts/reminders. Some people develop “protection-based” symptoms. These are symptoms that seem well-intentioned, like being hypervigilant our tough (emotionally numb) so the thing doesn’t happen to you again, but it comes at a cost…ongoing PTSD.

Other examples of avoidance strategies:

  1. Suppressing one’s thoughts – either intentionally or unintentionally.
  2. Deficits in memory – many patients don’t realize but they unintentionally block out many unrelated memories surrounding the trauma.
  3. Dissociation – this is when a patient “zones out” when confronted with a situation is bringing them back where they don’t want to go. We all have something called an autobiographical memory which works in the background all the time and let’s us know who we are. These are made up of memories about eras of our lives (e.g., schooling days); about general themes we hold important (e.g., times we overcame challenges, first-time we…); individual events that we recall vividly. When dealing with memories of trauma, we tend to revisit these memories as if we were observers – like watching it in a movie – rather than revisiting with the same presence like when we first experienced it. This distance – “observer perspective” – we place between ourselves and our own memories is an avoidance strategy commonly seen in PTSD. It can be severe enough that the patient has no recollection of being “present” during the dissociation, kind of like temporarily losing one’s connection to one’s identify, thoughts and emotions.
  4. Maladaptive behaviours – like going to bed late to avoid nightmares.
  5. Selective attention to potentially negative/threatening cues – like focusing always on the negative aspect, leading to hypervigilance/hyperarousal.
  6. Safety behaviours – like the development of obsessions and compulsions.
  7. Avoid reminders of trauma – like turning off the road every time you see a siren.
  8. Substance use.
  9. Rumination – thinking about aspects of what happened over and over again, e.g., I shouldn’t have gone out that morning, etc.
  10. Giving up/avoiding activities – like exercise, social engagements.
  11. Isolating oneself.


Consequences of Avoidance Strategies

Avoidance strategies limit a patient’s ability to:

  • Activate the memory of the trauma. It is important to activate the memory of the trauma because we need to process this memory to set ourselves free from the memory’s power over us.
  • Prove to ourselves that the triggers in and of themselves are not to be feared. if one never gets “back on the horse”, they can never prove to themselves that they shouldn’t fear riding a horse. Of course, injury is always a possibility but the risks and benefits should be weighed in a more objective manner.
  • Put the trauma’s memory into words. Putting a memory into language helps organize the memory and revisit it more objectively. For example, a patient who gets too obsessed that they didn’t save the kitten and just continues to ruminate on that may not have the opportunity to remember that the kitten was 500 meters away and getting there would have been impossible.

Avoidance strategies can also lead to the development of secondary emotions; emotions that develop in secondary to the consequences – social, physical, emotions, cognitive — of PTSD that just add insult to injury.


Changed (Disempowering) Core Beliefs

The trauma can change the way we look at ourselves or the world. Beliefs like:

  • I am incompetent
  • The world is a dangerous place
  • I deserve bad things
  • I am unlovable
  • I am defective
  • I should have done more

can start popping up. Obviously, these beliefs are not always true but patients begin to interpret everything on the touchstone of these beliefs. Then, only experiences that support these beliefs are acknowledged and those that don’t are discounted.

For example, a car driving down the road may be interpreted as barreling down on you to hit you. You step back on to the curb and think “if I didn’t step back on the curb, I would have been dead” without even considering that the car was pretty far away, was going to turn left, would have slowed down because it had a red light, etc. And then, upon stepping back on the curb, you trip and hurt your ankle and think “I deserve that because I don’t even know how to step up onto a curb right” rather than having noted that there was a small ledge there that was designed poorly.

CBT (Cognitive Behavioural Therapy) is focused on identifying these thoughts, evaluating their validity (or lack thereof) and remodelling them to fit better into your lifestyle.


Secondary Emotions

What are secondary emotions? Well, they stem from primary emotions. So, what are primary emotions? They are the most basic of human emotions that are consistent between cultures (Elfenbein & Ambady, 2002). They are hardwired in some of the oldest parts of our brains like the thalamus, hypothalamus and limbic system(Ekman, 1992). We can easily identify them in others just by watching (Fridland, Ekman, & Oster, 1987). They are those of anger, disgust, fear, happiness, sadness and surprise.

So, take the example of a person who is sad because of the trauma they experienced. They may become ashamed because they have come to believe that they are supposed to be cheerful and they are letting down their family by not “getting over it”…Shame would be a secondary emotion stemming from their feeling of sadness and their beliefs about sadness.

Basically, secondary emotions involve the reaction of the thinking-part of our brains (i.e., the cortex) to primary emotions. So, we have an emotion and then a thought that accompanies this emotion (cognitive appraisal); and then another (secondary) emotion to the thought associated with the first emotion.

Another example would be the fear of falling. That fear can lead to the secondary emotion of joy like on a roller coaster – have you ever been so afraid that you started cracking up? But, that fear can also lead to the secondary emotion of guilt or even anger being talked onto a roller coaster you didn’t want to be on.

Common secondary emotions in PTSD patients are shame, guilt and placing blame on themselves for what happens. This further weakens one’s self-esteem and needs to be addressed in the treatment plan.

Bisson JI, Cosgrove S, Lewis C, Robert NP. Post-traumatic stress disorder. BMJ. 2015;351:h6161. Published 2015 Nov 26. doi:10.1136/bmj.h6161

Brewin, Chris & Andrews, Bernice & Valentine, John. (2000). Meta-Analysis of Risk Factors for Posttraumatic Stress Disorder in Trauma-Exposed Adults. Journal of consulting and clinical psychology. 68. 748-66. 10.1037/0022-006X.68.5.748.

Ekman, P. (1992). Are there basic emotions? Psychological Review, 99(3), 550–553.

Elfenbein, H. A., & Ambady, N. (2002). On the universality and cultural specificity of emotion recognition: A meta-analysis. Psychological Bulletin, 128, 203–23.

Foa EB, Kozak MJ. Emotional processing of fear: exposure to corrective information. Psychol Bull 1986; 99:20.

Foa EB, Steketee G, Rothbaum BO. Behavioral/cognitive conceptualizations of post-traumatic stress disorder. Behav Ther 1989; 20:155.

Fridlund, A. J., Ekman, P., & Oster, H. (1987). Facial expressions of emotion. In A. Siegman & S. Feldstein (Eds.), Nonverbal behavior and communication (2nd ed., pp. 143–223). Hillsdale, NJ: Lawrence Erlbaum Associates.

Goldstein, Risë & Smith, Sharon & Chou, S. & Saha, Tulshi & Jung, Jeesun & Zhang, Haitao & Pickering, Roger & Ruan, Wenjing & Huang, Boji & Grant, Bridget. (2016). The epidemiology of DSM-5 posttraumatic stress disorder in the United States: results from the National Epidemiologic Survey on Alcohol and Related Conditions-III. Social Psychiatry and Psychiatric Epidemiology. 51. 10.1007/s00127-016-1208-5.

Kessler, Ronald & Rose, Sherri & Koenen, Karestan & Karam, Elie & Stang, Paul & Stein, Dan & Heeringa, Steven & Hill, Eric & Liberzon, Israel & Mclaughlin, Katie & SA, McLean & Pennell, Beth & Petukhova, Maria & Rosellini, Anthony & Ruscio, Ayelet & Shahly, Victoria & Shalev, Arieh & Silove, Derrick & Zaslavsky, Alan & Viana, Maria. (2014). How well can post‐traumatic stress disorder be predicted from pre‐trauma risk factors? An exploratory study in the WHO World Mental Health Surveys. World Psychiatry 13: 265-274. World Psychiatry. 13. 265-274. 10.1002/wps.20150.

Kessler, Ronald & Chiu, Wai & Demler, Olga & Merikangas, Kathleen & Walters, Ellen. (2005). Prevalence, Severity, and Comorbidity of 12-Month DSM-IV Disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry. 62. 590-592. 10.1001/archpsyc.62.7.709.

Kessler, Ronald & Berglund, Patricia & Demler, Olga & Jin, Robert & Merikangas, Kathleen & Walters, Ellen. (2005). Lifetime Prevalence and Age-of-Onset Distributions of DSM-IV Disorders in the National Comorbidity Survey Replication. Archives of general psychiatry. 62. 593-602. 10.1001/archpsyc.62.6.593.

Kessler, Ronald & Sonnega, Shelby & Bromet, EJ & Hughes, Michael & Nelson, Christopher. (1996). Posttraumatic Stress Disorder in the National Comorbidity Survey. Archives of general psychiatry. 52. 1048-60. 10.1002/1099-1298(200011/12)10:6<475::AID-CASP578>3.0.CO;2-F.

Koenen, K. C., Ratanatharathorn, A., Ng, L., McLaughlin, K. A., Bromet, E. J., Stein, D. J., & Karam, E. G. (2017). Posttraumatic stress disorder in the world mental health surveys. Psychological Medicine , 47 (13), 2260-2274.

Kroll, Jerome. (2003). Posttraumatic Symptoms and the Complexity of Responses to Trauma. JAMA : the journal of the American Medical Association. 290. 667-70. 10.1001/jama.290.5.667.

Leeies, Murdoch & (Hons, Jina & Sareen, Jitender & F.R.C.P.C, James. (2010). The use of alcohol and drugs to self‐medicate symptoms of posttraumatic stress disorder. Depression and Anxiety. 27. 731 – 736. 10.1002/da.20677.

Liebschutz, Jane & Saitz, Richard & Brower, Victoria & Keane, Terence & Lloyd-Travaglini, Christine & Averbuch, Tali & Samet, Jeffrey. (2007). PTSD in Urban Primary Care: High Prevalence and Low Physician Recognition. Journal of general internal medicine. 22. 719-26. 10.1007/s11606-007-0161-0.

O’Donovan, Aoife & Cohen, Beth & Seal, Karen & Bertenthal, Dan & Margaretten, Mary & Nishimi, Kristen & Neylan, Thomas. (2014). Elevated Risk For Autoimmune Disorders In Iraq And Afghanistan Veterans With Posttraumatic Stress Disorder. Biological Psychiatry. 77. 10.1016/j.biopsych.2014.06.015.

Rothbaum BO, Davis M. Applying learning principles to the treatment of post-trauma reactions. Ann N Y Acad Sci 2003; 1008:112.

Sareen, Jitender & Erickson, Julie & Medved, Maria & Asmundson, Gordon & Enns, Murray & Stein, Murray & Leslie, William & Doupe, Malcolm & Logsetty, Sarvesh. (2013). Risk factors for post-injury mental health problems. Depression and anxiety. 30. 10.1002/da.22077.

Smid, Geert & Mooren, Trudy & Mast, Roos & Gersons, Berthold & Kleber, Rolf. (2009). Delayed Posttraumatic Stress Disorder: Systematic Review, Meta-Analysis, and Meta-Regression Analysis of Prospective Studies. The Journal of clinical psychiatry. 70. 1572-82. 10.4088/JCP.08r04484.

Spitzer, Carsten & Barnow, Sven & Völzke, Henry & John, Ulrich & Freyberger, Harald & Grabe, Hans. (2009). Trauma, Posttraumatic Stress Disorder, and Physical Illness: Findings from the General Population. Psychosomatic medicine. 71. 1012-7. 10.1097/PSY.0b013e3181bc76b5.

Stein, Murray & Mcquaid, John & Pedrelli, Paola & Lenox, Rebecca & McCahill, Margaret. (2000). Posttraumatic stress disorder in the primary care medical setting. General hospital psychiatry. 22. 261-9. 10.1016/S0163-8343(00)00080-3.

Van Ameringen, Michael & Mancini, Catherine & Patterson, Beth & Boyle, Michael. (2008). Post-Traumatic Stress Disorder in Canada. CNS neuroscience & therapeutics. 14. 171-81. 10.1111/j.1755-5949.2008.00049.x.

Vieweg, Walter & Julius, Demetrios & Fernandez, Antony & Beatty-Brooks, Mary & Hettema, John & Anand, Karthika. (2006). Posttraumatic Stress Disorder: Clinical Features, Pathophysiology, and Treatment. The American journal of medicine. 119. 383-90. 10.1016/j.amjmed.2005.09.027.

Yehuda, Rachel & Hoge, Charles & Mcfarlane, Alexander & Vermetten, Eric & Lanius, Ruth & Nievergelt, Caroline & Hobfoll, Stevan & Koenen, Karestan & Neylan, Thomas & Hyman, Steven. (2015). Post-traumatic stress disorder. Nature Reviews Disease Primers. 15057. 10.1038/nrdp.2015.57.

Last update: November 2019