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What Makes an Event Traumatic?

By Dr. Stephen Fleming, PhD, C. Psych.

Although the Diagnostic and Statistical Manual (4th ed.) (DSM-IV) defines posttraumatic stress disorder (PTSD) as exposure to a traumatic event during which one experiences fear, helplessness, or horror, diagnosing such a disorder is no simple task because it requires an appreciation of both the stressful event and the individual’s reaction to it.

The DSM-IV offers a nonexhaustive list of traumatic events which, if experienced or witnessed, may lead to symptoms of PTSD. Military combat, violent personal assault, kidnapping, torture, natural or manmade disasters, severe automobile accidents, or being diagnosed with a life-threatening illness are all examples of traumatic events which, if experienced directly, may evoke posttraumatic stress. Witnessing death or serious injury from war, violent assault, or accidents also increases the risk of a traumatic response. Finally, one need not directly experience or observe an event for it to be potentially traumatic; events experienced by others that one learns about also have this potential (e.g., serious accident or injury of a loved one, hearing of the sudden death of a family member or close friend, or learning that one’s child has a life-threatening disease).

Characteristic responses to a traumatic stressor include symptoms of re-experiencing, avoidance, and increased arousal. Reexperiencing refers to intrusive, unbidden remembering or reliving of the traumatic event through dreams, nightmares, and flashbacks with accompanying feelings that the trauma is recurring. The second criterion, avoidance, occurs when one actively avoids stimuli reminiscent of the trauma (e.g., thoughts, feelings, and conversations associated with the trauma and reminders of the event); this may also extend to amnesia for significant aspects of the incident Also subsumed under this criterion is decreased interest and participation in previously-enjoyed activities, emotional withdrawal, and an inability to feel emotions as sharply as one did prior to the traumatic episode. Lastly, persistent symptoms of increased arousal (not present before the trauma) are often present; these include difficulty falling or staying asleep, irritability or outbursts of anger, concentration problems, hypervigilance, and an exaggerated or startle response.

Interestingly, exposure to a traumatic event is a necessary but not sufficient cause of PTSD. Consider that 75% of the general population has experienced an event that meets the stressor criteria for PTSD yet only about 25% ultimately develop PTSD (Meichenbaum, 1994). What are the factors that could account for differences between exposure to a traumatic event and the development of this disorder? To answer this question, one must look at the interaction between trauma magnitude and a host of victim variables including the victim’s phenomenological and narrative response and social resources and support (Briere, 1997).

With respect to characteristics of the stressor, it has been consistently demonstrated that the subsequent risk of developing PTSD is directly proportionate to the magnitude of the stressor. Such variables as the threat of physical injury or death, the degree of violence during a sexual assault, the death of a significant person in one’s life, and, in combat, the more intense and frequent the violence, all tend to increase the magnitude of the stressor and increase the likelihood of PTSD.

Numerous victim characteristics have also been shown to play a major role in the development of PTSD. The risk is increased if one has experienced previous psychological dysfunction or disorder, suffered prior trauma, has an unstable family history, or has a genetic predisposition. Adjustment to a traumatic event is also influenced by the meaning assigned to it. Exposure has the potential to overwhelm one’s sense of safety and security and shatter the belief that life is orderly, predictable, controllable, and fair. Finally, research has consistently shown that if one has a warm and supportive posttrauma social network (family, friends, helping professionals) it is much less likely that PTSD will develop following a stressful event. In summary, whether or not one develops PTSD following trauma is a surprisingly complex issue involving characteristics of the stressor, victim variables (including the meaning of the event), and the availability of social support.


American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorderes (4TH ed.). Washington,D.C.

Briere, J. (1997). Psychological assessment of adult posttraumatic states. American Psychological Association. Washington,D.C.

Meichenbaum,D. (1994). A clincial handbook/practical therapist manual. Institute Press.Waterloo,Ontario.

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