139 Post-Traumatic Stress Disorder

Learning Objectives

By the end of this section, you will be able to:

  • Describe the nature and symptoms of PTSD
  • Identify the risk factors and protective factors linked to PTSD
  • Identify and describe current treatment options for PTSD

In the following section, we will discuss Post-Traumatic Stress Disorder (PTSD), a term used to describe a set of fear and arousal-related symptoms tied to a specific traumatic event or events. In approaching this content, we acknowledge that some readers may have personal experience with these kinds of trauma, and may be negatively affected by this material. 

If you, or someone you know, is dealing with PTSD, supports are available through Wellness Canada that may be helpful. 

Originally, PTSD was identified in the military after combat exposure and was referred to as shell shock or combat neurosis, and was mainly diagnosed in male combat veterans. In Waiting for First Light, Canadian General Romeo Dallaire shares his continuing struggles with PTSD after witnessing atrocities during the genocide in Rwanda in 1993-94. As head of the United Nations peacekeeping force, his experience left a lasting impact on his mental health and led to his medical dismissal from the military several years later. He has devoted his life to mental health advocacy for veterans and fighting exploitation of child soldiers through the Dallaire Institute for Children, Peace, and Security at Dalhousie University. Although long recognized as a significant mental health concern, there is stigma surrounding PTSD in this population and effective treatments still remain inaccessible to many that need them.

The kinds of traumas that cause these symptoms vary widely and have the ability to affect anyone. It wasn’t until the late 1970’s that the broader medical community acknowledged that the same set of symptoms could be seen in people who experienced sexual assault, so the more general term post-traumatic stress disorder was developed to include other kinds of psychological trauma (Herman, 1997).

A Broader Definition of PTSD

According to the DSM-5, PTSD is diagnosed when an individual who has had a traumatic experience develops a set of fear and arousal related symptoms that last at least a month. The individual may have been present for the traumatic event as a victim or a witness, or they may have second hand exposure to the event from someone who was present.

The symptoms of PTSD fall into four categories: Intrusion, Avoidance, Negative alterations in cognition and mood, and Alterations in arousal and reactivity. Intrusion symptoms occur when the traumatic event is re-experienced through memories, nightmares, flashbacks, and emotional or physical reactivity after exposure to stimuli associated with the trauma. Flashbacks occur when the individual relives the event, as if it is currently happening and can last from a few seconds to several days (APA, 2013a). Avoidance occurs when the individual avoids stimuli or thoughts and feelings associated with the trauma. Alterations in cognitions and mood involve pervasive negative mood, feelings of isolation, extreme negative beliefs about the self or the world, and problems with memory, often specific to trauma related memories. Alterations in arousal and reactivity include irritability or aggression, increased risk-taking, hyper-vigilance, jumpiness, and difficulty with concentration or sleep (APA, 2013a).

Complex PTSD (C-PTSD) is a variant of PTSD included in the 11th revision of the International Classification of Diseases (ICD-11) but it has yet to be included in the DSM. Complex PTSD generally results from prolonged or repeated instances of trauma from which escape is difficult or impossible, like childhood neglect or domestic abuse. Diagnosis of C-PTSD requires the presence of intrusions, avoidance, and alterations in arousal and hyperactivity (three core features of PTSD), as well as extreme emotional dysregulation, persistent interpersonal difficulties, and negative self-concept (ICD-11, 2019). As a result of these differences, people with C-PTSD may often be misdiagnosed as having Borderline Personality Disorder (BPD). There is a high rate of comorbidity between C-PTSD and BPD, however, research has supported the validity of C-PTSD as a distinct construct and different treatment courses are indicated (Cloitre et al, 2014).

Roughly 8% of adults in Canada meet the clinical criteria for PTSD, and of those close to 4 in 5 report barriers in accessing care. Among those who meet the criteria for PTSD, sexual assault is the most commonly reported cause (14%), followed by life threatening illness or injury (10%), situations involving sudden accidental death (6%), and physical assault (6%) (Statistics Canada, 2022). As mentioned above, some people may be at higher risk of experiencing trauma as a result of their occupation but there are also identity factors that are associated with increased risk. People in these groups aren’t less resilient, but they’re more likely to experience traumatic events as a result of prejudice.  Because of systemic factors, these groups may also be more likely to encounter barriers when seeking assistance (Asnaani & Clark-Hall, 2017). 

Risk Factors For PTSD

Of course, not everyone who experiences a traumatic event will go on to develop PTSD. Trauma is complex, and a variety of factors have been identified as increasing one’s risk of developing PTSD. Some of the risk factors for PTSD can be considered individual risk factors, involving the coping strategies and resources an individual has to deal with trauma. For example, people who experience trauma  Individual factors like genetics and coping strategies are important in assessing risk for PTSD, but they also interact with environmental factors, which affect everyone in a shared environment. By considering how individual risk factors interact with environmental risk factors, we can investigate what allows some people to recover more quickly from trauma while others go on to develop PTSD. To understand risk factors in context, we will examine the impact of the Covid-19 pandemic on frontline healthcare workers (HCW’s).

Even before the pandemic, HCW’s were at a higher risk of exposure to traumatic events than the general population. During the pandemic frontline workers were exposed to even higher rates of patient death and suffering, while hospital understaffing and an increased need for beds meant working long hours without rest. On top of this, many hospitals lacked sufficient supplies and as a result HCW’s had to put themselves at risk with inadequate personal protective equipment during a time when the virus was not well understood. In some cases, HCW’s had to improvise, using garbage bags to wear over scrubs, or reusing masks that were meant to be disposed after use (CIDRAP, 2020). One study estimates that the prevalence of PTSD among HCW’s in China increased from 10.37% to 20.84% between June 2020 and June 2021, and combined data from 65 studies conducted across 21 countries during the pandemic reported that of 21.5% of HCW’s involved met criteria for PTSD (Ouyang et al., 2022; Li et al., 2021).

So what factors predicted the development of PTSD in these populations? Risk factors that preceded traumatic experience were younger age and a lack of experience or training- younger, HCW’s have had less time to develop and practice job-specific coping mechanisms than those who have been in the field for years.  Risk factors that were present after trauma included heavy workload, an unsafe work environment, passive coping, and burnout. Passive coping strategies involve disengaging or distracting oneself from the source of stress, and burnout is a form of mental exhaustion from prolonged emotional, physical, and mental stress, and is often work-related. Low social support was identified as a risk factor both before and after traumatic experience. In this context, an HCW who uses passive coping is more at risk of developing PTSD than coworkers with more effective coping strategies, even though they share the environmental risk factors like a heavy workload and an unsafe working environment. Many of these risk factors are also associated with poorer patient care. Since the pandemic, many suggestions have been made to prevent or reduce these poor outcomes, often including a ban on prolonged working hours, and better availability of counselling services (d’Ettorre et al., 2021).


Figure PY.23 Frontline medical workers experienced high rates of trauma during the Covid-19 pandemic, and have subsequently been at a heightened risk of developing symptoms of PTSD. In this image, Dr. Annalisa Silvestri sits on the floor in a hallway of San Salvatore Hospital in Italy, wearing full personal protective equipment. This image was taken at the end of a 12 hour day for Dr. Silvestri during which she was unable to take a break. This was a common experience for medical professionals globally throughout the pandemic. Image credits: Alberto Giuliani, wikimedia commons 2020.

Support For Sufferers of PTSD

Research has shown that social support following a traumatic event can reduce the likelihood of PTSD (Ozer, Best, Lipsey, & Weiss, 2003). Social support is often defined as the comfort, advice, and assistance received from relatives, friends, and neighbors. Social support can help individuals cope during difficult times by allowing them to discuss feelings and experiences and providing a sense of being loved and appreciated. One study conducted with HCW’s in Northern Italy during the height of the pandemic found that high social support was significantly correlated with recovery,  even for people with higher than average levels of PTSD symptoms (Fino et al., 2001).

There are also a number of promising clinical treatments/psychotherapeutic strategies for PTSD, including Exposure Therapy, Cognitive Behavioural Therapy (CBT), Eye Movement Desensitization and Reprocessing (EMDR), and Psychedelic Therapies. These therapies all focus on the individual’s experience of the traumatic memory and use different techniques to weaken the links between traumatic stimuli and extreme emotional and physiological reactions. Both exposure therapy and CBT can be understood by considering the Learning and Cognitive Processing Model of PTSD, which suggests that some symptoms are developed and maintained through classical conditioning. The traumatic event may act as an unconditioned stimulus that produces an unconditioned response of extreme fear and anxiety. Cognitive, emotional, physiological, and environmental cues related to the event are conditioned stimuli and so also become linked with the trauma. These traumatic reminders evoke conditioned fear and anxiety, similar to those caused by the event itself (Nader, 2001).

Exposure therapy works to retrain the autonomic nervous system, the branch of the nervous system that activates the fight or flight response. Through this, exposure therapy aims to teach the traumatized individual how to remain calm in the face of trauma-related stimuli, weakening the conditioned response. Similarly, CBT aims to identify and alter thoughts, beliefs and behaviours triggered by trauma related stimuli, and it is sometimes combined with exposure therapy (Kar, 2011). For example, if one associates a certain song with an instance of trauma, exposure therapy might have the individual listen to snippets of the song while working to relax the nervous system. CBT could involve identifying negative thoughts that come up when the song is heard, so that those thoughts can be refuted and replaced with more positive ones.

EMDR and Psychedelic therapies are not as well established, but meta-analyses have indicated that EMDR can significantly reduce PTSD symptoms (Wilson et al., 2018), and early results in studies of psychedelic therapies are promising. These therapies can be understood through the Adaptive Information Processing model of PTSD, which suggests that past trauma can continue to cause emotional distress if the memory of that trauma is not fully processed (Solomon & Shapiro, 2008). If memories of traumatic events are fragmented and lacking in detail, the individual may be unable to remember the event in a way that gives it context and meaning. As a result, the fragmented memory stands out, resulting in intrusive thoughts. In this view, EMDR involves reprocessing the memory by talking through it with a therapist while experiencing bilateral stimulation. This usually involves visually following a dot of light moving back and forth with the eyes, and has been correlated with a reduction of vividness and emotion associated with the memory (Maxfield et al., 2008). A number of clinical trials have found EMDR to be significantly more effective than placebo in reducing symptoms of PTSD, and in many cases this was comparable to, or greater than drug treatments or other forms of therapy (Wilson et al., 2018). 

Psychedelic therapy involves reprocessing traumatic memories under the influence of hallucinogenic drugs with the guidance of therapeutic supervision. The mechanism of action depends on which drug is being used, but the idea is that these compounds alter certain neural networks so that memories can more easily be reprocessed. For example, MDMA has been shown to reduce the activity of the amygdala, a brain structure involved in the encoding of fearful memories. It also increases the activity of the prefrontal cortex, an area of the brain that has been shown to be less active in people with PTSD (Carhart-Harris et al., 2015). Classical psychedelic drugs, like LSD and psilocybin, have been shown to help weaken learned fear responses in animals and promote neural plasticity (Catlow et al., 2013; Ly et al., 2018), which theoretically allows the sufferer to alter the neural connections that underlie their traumatic memories . These psychedelic therapies are promising avenues for the future treatment of PTSD with the possibility of significant reductions in symptoms after only a few sessions. Importantly, positive outcomes with these drugs are associated with guidance from professionals trained in psychedelic therapies. Psychedelic treatment without trained guidance can lead to negative outcomes, so it’s important to ensure this treatment is conducted by specialists in the field  (Krediet et al., 2020).

PTSD and trauma can have a massive effect on an individual’s well- being and daily functioning. Moving forward  it is important to continue refining treatments and working to make them accessible to everyone who needs them.


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Introduction to Psychology & Neuroscience (2nd Edition) Copyright © 2020 by Edited by Leanne Stevens & Jennifer Stamp is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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