What Is Post-Traumatic Stress Disorder?

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Post-traumatic stress disorder (PTSD) is a psychiatric disorder involving extreme distress and disruption of daily living that happens after exposure to a traumatic event. About 6% of the U.S. population will experience PTSD during their lives.

To diagnose PTSD, a mental health professional references the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and evaluates whether or not the patient meets the criteria. The criteria in the fifth edition are somewhat different than the criteria in the fourth edition.

Symptoms of PTSD

The DSM-5 divides PTSD symptoms into four categories:

These symptoms are associated with a traumatic event. Each of the four categories includes a group of related symptoms.


These symptoms are related to intrusive thoughts and memories of the traumatic event.

  • Reoccurring, involuntary, and intrusive upsetting memories of the event
  • Repeated upsetting dreams related to the event
  • Dissociation (for example, flashbacks, feeling as though the event is happening again)
  • Strong and persistent distress to cues connected to the event that are either inside or outside of the body
  • Strong bodily reactions (for example, increased heart rate) when reminded of the event


People with PTSD may avoid people, places, conversations, activities, objects, or situations that bring up memories of the event. They may also avoid thoughts, feelings, or physical sensations that recall the event.

Negative Changes in Thoughts and Mood

People with PTSD may experience a pervasive negative emotional state (for example, shame, anger, or fear). Other symptoms in this category include:

  • Inability to remember an important aspect of the event
  • Persistent and elevated negative evaluations about oneself, others, or the world (for example, "I am unlovable," or "The world is an evil place")
  • Elevated self-blame or blame of others about the cause or consequence of the event
  • Loss of interest in previously enjoyable activities
  • Feeling detached from others
  • Inability to experience positive emotions (for example, happiness, love, joy)

Changes in Arousal and Reactivity

People with PTSD often feel constantly "on guard" or like danger is lurking around every corner (also known as hypervigilance). Related symptoms include:

  • Difficulty concentrating
  • Heightened startle response
  • Impulsive or self-destructive behavior
  • Irritability or aggressive behavior
  • Problems sleeping

Diagnosis of Post-Traumatic Stress Disorder

The first criteria for a diagnosis of PTSD listed in the DSM-5 is exposure to one or more traumatic event(s), which is defined as one that involved death or threatened death, actual or threatened serious injury, or actual or threatened sexual violence.

Experiencing the event could be direct, but it doesn't have to be. Exposure could also occur indirectly, such as:

  • Witnessing the event as it occurred to someone else
  • Learning about an event where a close friend or relative experienced an actual or threatened violent or accidental death
  • Having repeated exposure to distressing details of an event, such as a police officer repeatedly hearing details about child sexual abuse

Once the exposure has occurred, PTSD symptoms are evaluated for a diagnosis.

DSM-5 PTSD Diagnosis

In order to be diagnosed with PTSD, the following criteria should be met:

  • Exposure to the traumatic event
  • One (or more) intrusion symptom(s)
  • One (or more) symptom(s) of avoidance
  • Two (or more) symptoms of negative changes in feelings and mood
  • Two (or more) symptoms of changes in arousal or reactivity

These symptoms also must:

  • Last for longer than one month
  • Bring about considerable distress and/or interfere greatly with a number of different areas of life
  • Not be due to a medical condition or substance use

Changes in the DSM-5

The biggest change in the DSM-5 is removing PTSD from the category of anxiety disorders and putting it in a classification called "Trauma- and Stressor-Related Disorders."

Other key changes include:

  • More clearly defining what kind of events are considered traumatic
  • Adding different types of exposure to the event
  • Increasing the number of symptom groups from three to four by separating avoidance symptoms into their own group
  • Changing the wording of some of the symptoms
  • Adding a new set of criteria for children aged 6 or younger
  • Eliminating acute and chronic phases
  • Introducing a new specifier called dissociative features


PTSD is caused by exposure to trauma. However, it's not clear why some people develop PTSD after traumatic events while others do not. There are some risk factors that can make someone more likely to develop it than others. For example, genetics may play a role. It's also more common in women than men.

Other risk factors include:

  • A lack of social support following the event
  • An experience of past trauma
  • History of mental illness
  • History of substance use


There are different types of PTSD, including:

  • Complex PTSD: Characterized by a series of traumatic events occurring over time and typically earlier in life. Notably, complex PTSD is not listed in the DSM-5.
  • Delayed expression: Before the DSM-5, this type of PTSD was referred to as "delayed onset." It occurs when someone is diagnosed at least six months after the traumatic event took place.
  • Dissociative: In addition to meeting criteria for a PTSD diagnosis, this subtype—classified specifically as "with dissociative symptoms"—requires symptoms of depersonalization or derealization.

Acute stress disorder is related to PTSD. While it shares some symptoms, a PTSD diagnosis requires symptoms are present for more than a month, whereas someone with acute stress disorder could experience symptoms for just three days to one month.

Acute and chronic PTSD are no longer used in the DSM-5. Acute referred to PTSD symptoms lasting less than three months and chronic referred to symptoms lasting more than three months.


Treatment for PTSD can involve medication, psychotherapy, or both. Consult a mental health professional to find the best treatment for you.


Antidepressants, specifically selective serotonin reuptake inhibitors (SSRIs), are typically considered the first-line medication option to treat PTSD. These can help someone with PTSD with mood, anxiety, eating, and sleep.

Zoloft (sertraline) and Paxil (paroxetine) are FDA-approved to treat PTSD. Other drugs that have been shown to be effective for PTSD include Prozac (fluoxetine) as well as Effexor XR (venlafaxine), which is a selective norepinephrine reuptake inhibitor (SNRI). In addition, there are other medications that may be used to treat PTSD. Be sure to discuss your options with your healthcare provider.


Cognitive behavioral therapy (CBT) is a form of talk therapy that has been found to be effective for treating the symptoms of PTSD. CBT may help manage your symptoms by working to change your beliefs and behaviors. Other types of psychotherapy that may be used for PTSD include:


PTSD gets in the way of everyday life, and it's important to take good care of yourself to manage it. These ways to cope are known to be effective.

  • Mindfulness practice
  • Support groups and supportive relationships with loved ones
  • Abstinence from drugs and alcohol
  • Exercise

If you or a loved one are struggling with PTSD, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

Frequently Asked Questions

  • What is the DSM-5 criteria for PTSD?

    The DSM-5 criteria for PTSD include, first, direct or indirect exposure to a traumatic event, followed by symptoms in four categories: intrusion, avoidance, negative changes in thoughts and mood, and changes in arousal and reactivity.

    The DSM-5 criteria also state that the symptoms must last for at least a month, cause considerable distress and/or interfere with life, and not be caused by another medical condition or by substance use.

  • What are the symptoms of PTSD?

    Symptoms of PTSD can vary in severity and not everyone with PTSD will have the same symptoms. But common symptoms include:

    • Intrusive thoughts, flashbacks, and/or dreams of the traumatic event
    • Physical reactions when reminded of the event
    • Avoidance of people, places, situations, etc., that elicit memories of the event
    • Pervasive negative emotional state, such as shame, anger, or fear
    • Hypervigilance
    • Irritability
    • Impulsive behavior
    • Difficulty sleeping
  • What is complex PTSD?

    Complex post-traumatic stress disorder (complex PTSD or C-PTSD) is not an official diagnosis in the DSM-5. But it typically refers to PTSD resulting from prolonged, repeated trauma—usually, childhood trauma.

    Complex PTSD has the same symptoms as PTSD, along with additional symptoms including difficulty controlling emotions, negative self-view, difficulty with relationships, detachment from the trauma, and loss of a system of meanings.

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Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Matthew Tull, PhD
Matthew Tull, PhD is a professor of psychology at the University of Toledo, specializing in post-traumatic stress disorder.