Is PTSD a Mental Illness? PTSD in the DSM-5

The question as to whether PTSD is a mental illness has been asked for years. Learn about posttraumatic stress disorder and its DSM-5 criteria on HealthyPlace.

Some people ask whether posttraumatic stress disorder (PTSD) is a mental illness. According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the manual that medically defines all mental illnesses, PTSD is an official mental illness.

What Is a Mental Illness?

According to The American Heritage® Stedman's Medical Dictionary, “mental illness" is defined as:

Any of various disorders characterized chiefly by abnormal behavior or an inability to function socially, including diseases of the mind and personality and certain diseases of the brain. Also called mental disease, mental disorder.

In the case of those who have PTSD, they experience significant, abnormal behavior. Examples of this might be diving to the floor when a car backfires or feeling as though they are reliving the traumatic events, even to the point of hallucinating (Understanding PTSD Nightmares And Flashbacks).

PTSD in the Diagnostic and Statistical Manual of Mental Disorders

Posttraumatic stress disorder has been a recognized mental illness since 1980 when it was included in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III). It was considered quite controversial at the time, but since then doctors and researchers agree that PTSD is a mental illness.

While some people may argue that the physical and emotional effects of PTSD are reasonable experiences after a traumatic event, and, thus, do not constitute a disease, this perspective is not shared by medicine.

Posttraumatic Stress Disorder in the DSM-5: Criteria Clusters

Between the DSM-IV and the DSM-5, there have been some changes to the criteria for PTSD. Currently, there are considered to be eight criteria for a PTSD diagnosis. The first of the PTSD criteria include:

  • Directly experiencing the traumatic event(s)
  • Witnessing, in person, the event(s) as it occurred to others
  • Learning that the traumatic event(s) occurred to a close family member or friend
  • Experiencing repeated or extreme exposure to aversive details of the traumatic event(s); this does not apply to exposure through media such as television, movies, or pictures

The second PTSD criterion consists of symptoms involving re-experiencing:

  • Thoughts or perception
  • Images
  • Dreams
  • Illusions or hallucinations
  • Dissociative flashback episodes
  • Intense psychological distress or reactivity to cues that symbolize some aspect of the event

The third criterion for a PTSD diagnosis involves the avoidance of stimuli that remind the person of the traumatic event:

  • Avoidance of thoughts, feelings, or conversations associated with the event
  • Avoidance of people, places, or activities that may trigger recollections of the event

The fourth of the PTSD criteria involves persistent negative thoughts, mostly associated with the traumatic event:

  • Inability to remember an important aspect of the event(s)
  • Persistent and exaggerated negative beliefs about oneself, others, or the world
  • Persistent, distorted cognitions about the cause or consequences of the event(s)
  • Persistent negative emotional state
  • Markedly diminished interest or participation in significant activities
  • Feelings of detachment or estrangement from others
  • Persistent inability to experience positive emotions

The fifth of the PTSD diagnosis criteria involves an increase in arousal (often noted as feeling “keyed up”) and reactivity:

  • Irritable behavior and angry outbursts
  • Reckless or self-destructive behavior
  • Hypervigilance
  • Exaggerated startle response
  • Concentration problems
  • Sleep disturbance

The remaining three PTSD diagnosis criteria are:

  • The duration of symptoms is more than 1 month
  • The disturbance causes clinically significant distress or impairment in functioning
  • The disturbance is not attributable to the physiological effects of a substance or other medical condition

The number of symptoms that are required for a PTSD diagnosis depends on the criteria cluster.

article references

APA Reference
Tracy, N. (2021, December 28). Is PTSD a Mental Illness? PTSD in the DSM-5, HealthyPlace. Retrieved on 2024, May 27 from

Last Updated: February 1, 2022

Medically reviewed by Harry Croft, MD

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