Chapter 9 - PTSD

PSYC 300
Chapter 9 – Post Traumatic Stress Disorder
9.4 Post-Traumatic Stress Disorder (p. 268 – 277)
- Post-traumatic stress disorder (PTSD): an anxiety disorder in which a particularly stressful event
(e.g., military combat, rape, natural disaster) brings in its aftermath intrusive re-experiencing of
the trauma, a numbing of responsiveness to the outside world, estrangement from others, a
tendency to be easily startled, nightmares, recurrent dreams, and disturbed sleep.
 Entails an extreme response to a severe stressor, including increased anxiety, avoidance
of stimuli associated with the trauma, and a numbing of emotional responses.

Description, Symptoms, and Prevalence
- PTSD is defined by a cluster of symptoms.
- Unlike the definitions of other psychological disorders, the definition of PTSD includes part of its
presumed etiology  a traumatic event
- Definition of PTSD was changed considerably in DSM-5.
 In previous versions, the event was supposed to have created intense fear, horror, or
helplessness.
 It is now recognized that people can be variable in their emotional reactions,
- Significant change across versions of the DSM is what type of event is considered a trauma-
inducing event.
 Previous editions of DSM said traumatic event was defined as “outside the range of
human experience.”  traumatic event could be a life-threatening natural disaster
 Examining outside the range of human experience was considered too restrictive 
would rule out PTSD following automobile accidents, death of a loved one, or prolonged
exposure to abuse.
 Some consider the current definition too restrictive  it focuses on event's objective
characteristics rather than subjective meaning
- DSM-5 now specifies an event might have happened to the victim and witnesses.
 A person can experience trauma if it occurs to a family member or close friend rather
than themself  event only applies if it involved violence or an accident.
- Previous PTSD diagnostic criteria included 17 symptoms
- Current criteria involve 20 symptoms across four symptom categories
 Some symptoms remain but have wording changes in how they are described.
 Fourth general category has been newly added  looks at negative alterations in
cognitions and moods associated with the traumatic event.
- Other symptoms for PTSD are grouped into three major categories  diagnosis requires
symptoms last longer than one month.
1. Intrusion symptoms associated with the traumatic event.
 Intrusions come in various forms including distressing or memories.
 Individual frequently recalls the event and experiences nightmares about it.
 Intense emotional upset is produced by stimuli that symbolize the event
o E.g., thunder reminding a veteran of the battlefield
o E.g., anniversaries of some specific experience (e.g., death date)
2. Persistent avoidance of stimuli associated with the event beginning after the event has
occurred
 Person tries to avoid thinking about trauma or encountering stimuli that will bring it
to mind.
3. Marked alterations in arousal and reactivity associated with the traumatic event.
 Symptoms include irritable behaviour, reckless or self-destructive behaviour,
insomnia, difficulty concentrating, hypervigilance, and an exaggerated startle
response.

,  Lab studies have confirmed clinical symptoms by documenting heightened
physiological reactivity of PTSD participants to combat imagery and high-
magnitude startle responses
- More extreme trauma tends to have more impact in terms of the number of disorders and
associated levels of dysfunction (e.g., 911)
- There is a difference between PTSD and acute stress disorder
 Everyone experiences stress to a considerable degree.
 Acute Stress Disorder Diagnoses  if the stressor causes significant impairment in
social or occupational functioning that lasts for at least three days and less than one
month
o Proportion of people who develop acute stress disorder varies with the type of
trauma they experience.
o Following rape, the figure is extremely high (over 90%)
o Other traumas, e.g., mass shooting, motor vehicle accident have low figures,
(around 13% for motor accident victims)
o Although some get over acute stress disorder, many develop PTSD
- Prevalence of PTSD varies depending on how people are assessed.
- Lifetime prevalence of PTSD in Canada is almost 1 in 10 & one-month prevalence is about 1 in
25
 Prevalence varies depending on the severity of the trauma experienced
o About 3% among civilians exposed to a physical attack
o About 20% among people wounded in Vietnam War (war in general)
o About 50% among rape victims and people POWs (prisoners of war)
- Factors deemed to increase PTSD symptoms include community silence, limited help-seeking
(stigma of seeking help), and insufficient proactive provision of therapeutic resources

Etiology of Post-Traumatic Stress Disorder
- Research and theory on causes of PTSD focus on risk factors for the disorder, as well as
psychological and biological factors.

Risk Factors
- Important to consider not only the risk factors for PTSD, but the likelihood of being exposed to
trauma.
- Research indicates males have higher levels of trauma exposure across various event types,
except for child sexual abuse and sexual assaults, yet females have higher levels of PTSD
- Several risk factors for PTSD.
 Exposure to a traumatic event
 Predictors of PTSD
 Gender
 Perceived threat to life
 Early separation from parents
 Family history of a disorder
 Previous exposure to traumas
o Previous exposure to trauma is regarded as one of the strongest predictors of
whether the individual is exposed subsequently to trauma
 Pre-existing disorders (an anxiety disorder or depression)
- PTSD hyperarousal symptoms are uniquely predictive of traumatic stressors.
 Different types of PTSD symptoms play different roles in subsequent exposure to
different types of events.