What is PTSD? - Definition & Statistics

Instructor: Karin Gonzalez

Karin has taught middle and high school Health and has a master's degree in social work.

In this lesson, you will learn the definition of PTSD and the criteria necessary for a diagnosis of this mental disorder. You will then review some statistics that will help paint a picture of the prevalence of PTSD. Following the lesson will be a brief quiz to test your knowledge.

Definition of PTSD

According to the US Department of Veterans Affairs, also known as the VA, 11% of war veterans that come back from Afghanistan suffer from PTSD. That is about 1 in 10 veterans that experience this sometimes life-threatening mental disorder. Iraq War veterans suffer from PTSD at an even more alarming rate--20%, or 1 in 5 veterans.

Post-traumatic stress disorder, or PTSD, is a mental disorder where one experiences horrific memories, dissociative flashbacks, nightmares, heightened arousal, and depressive thoughts in the aftermath of encountering a severe traumatic event or events. A traumatic event is a scary and sometimes life-threatening incident, like fighting in a war or being trapped in a Category 5 hurricane, badly injured in a car wreck, robbed at gunpoint, raped, or held hostage.

The trauma of war can cause PTSD in soldiers and veterans.
Soldier at war

Criteria for Diagnosis of PTSD

PTSD is listed as a mental disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM). In order to learn about the criteria, or diagnostic requirements, for PTSD, let's look at Molly, a therapist with the VA, who is treating Bill, an Iraq War veteran.

  • 'Criterion A: Stressor'

Stressors include exposure to death, near-death, serious injury, or sexual violence. Bill meets this criterion because, as a soldier, he was directly exposed to the stressor: traumatic and deadly war battles. In fact, just witnessing a traumatic event, like war battles, could be enough to experience PTSD.

  • 'Criterion B: Intrusion symptoms'

Intrusion symptoms are the inability to keep memories from occurring and recurring. Think them as unwanted intruders in someone's mind. These symptoms can be in the form of memories, nightmares, or flashbacks (dissociative episodes where one relives the experience). Intrusion symptoms can also be prolonged distress, or intense negative reaction after being exposed to a trigger of the traumatic event. Bill only has one of these symptoms--recurrent negative memories that he cannot escape--but Molly tells Bill that he only needs one of these intrusion symptoms for a PTSD diagnosis.

  • 'Criterion C: Avoidance'

If something scared a child, he would usually try to avoid the object in the future. He wouldn't even want to think about it. Avoidance behaviors in PTSD are a severe form of this example. Just one type of avoidance behavior is required for a diagnosis of PTSD. For instance, Bill tries to avoid spending time with other veterans because they remind him of war. This has affected his life negatively because he and his family are missing out on important and helpful social supports.

  • 'Criterion D: Negative alterations in cognitions and mood'

Bill used to enjoy having an intimate relationship with his wife, but he no longer takes pleasure or an interest in that. He has difficulty finding joy in anything, even going to parties with his family--something that he used to love. He believes he is a bad person and blames himself for killing other people in war, even if it was his job to do so.

Bill is experiencing four symptoms of negative alterations in his thinking and mood, although he only needs two to meet the diagnostic criteria. The other symptoms that one could experience would be trauma-related emotions (fear, sadness, anxiety, worry, panic), feeling separated from others, or loneliness, and post-traumatic amnesia (not being able to recall significant details of the trauma).

This pie chart depicts the rates of coexistence of depression and PTSD in Iraqi and Afghanistan US Veterans deployed between Oct 2001 and 2007.
PTSD and Depression

  • 'Criterion E: Alterations in arousal and reactivity'

Bill wrecked his car while dangerously speeding (self-destructive, reckless behavior). He has difficulty sleeping at night due to nightmares. When someone taps him on the arm, he jumps back (exaggerated startle response). Bill is experiencing three out of the six possible symptoms for this criterion. Other symptoms in this criterion are irritable and aggressive behavior, hyper-vigilance, and problems with focus, attention, and concentration.

  • 'Criterion F: Duration'

Molly asks Bill how long he has been experiencing the symptoms, and Bill reports that he has been experiencing the symptoms for three months, since returning from war. PTSD diagnosis requires that symptoms endure for at least one month, so Bill meets this requirement.

  • 'Criterion G: Functional Significance'

The symptoms negatively affect Bill's ability to function in at least two areas of his life: family life and his social life.

  • 'Criterion H: Exclusion'

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