Types of Trauma

The word trauma covers experiences that differ a great deal in kind and in effect. Clinicians and researchers use several terms to tell them apart. Each has a meaning and limits, and some are still being studied.

By Hanouf Alahmari, MA, LMFT · Updated 17 September 2026

The basics

What is trauma?

There is no single definition that everyone uses. One widely used US framework describes trauma through three parts: an event or set of circumstances, the way a person experiences it as harmful or threatening, and effects on their wellbeing that last.1 The same event can affect two people very differently, and how it is experienced depends partly on culture, on the support available, and on the person's age at the time.1

An event or circumstances

Experienced as harmful or threatening

Effects that last

The three parts of trauma in one widely used US framework.1

Most of the terms on this page are descriptions rather than diagnoses, and none of them can be applied to a person from a list. Reading about them may bring up memories or feelings. It is fine to stop and come back later.

Diagnoses

How often and how long

Where the harm came from

Childhood adversity and smaller experiences

Diagnoses

How trauma is defined for a diagnosis

PTSD in the DSM-5-TR. Published in 2022, the DSM-5-TR defines the kind of event that a diagnosis of post-traumatic stress disorder (PTSD) can follow: actual or threatened death, serious injury, or sexual violence. A person may have experienced it directly, witnessed it, learned that it happened to a close family member or friend, or been exposed repeatedly to its details, usually through work.2 Watching events on screens does not count for this diagnosis unless it is part of someone's job, and some researchers question that rule for graphic footage shared on social media.3

The same chapter of the manual includes PTSD, acute stress disorder, adjustment disorders and, since the 2022 text revision, prolonged grief disorder. Each requires exposure to a traumatic or stressful event.2,4,5

PTSD and Complex PTSD in the ICD-11. Complex PTSD is a diagnosis in the World Health Organization's ICD-11 but not a separate diagnosis in the DSM-5-TR. It combines the core symptoms of PTSD with ongoing difficulty regulating emotions, a deeply negative view of oneself with shame or guilt, and difficulty feeling close to others. It most often follows trauma that was prolonged or repeated and hard or impossible to escape.6 Research has generally supported telling the two diagnoses apart.7

In ICD-11, both diagnoses share three core symptoms, and Complex PTSD adds three areas of difficulty.6,8

Strong reactions in the days after a frightening event are widely understood as a normal response, not a sign that something is wrong with the person.6 Some people may still want support during that time.

Most people who go through trauma do not develop PTSD

Large international surveys find that roughly 7 in 10 adults report at least one potentially traumatic event in their lifetime.9 Among people exposed to trauma, about 5.6% had PTSD at some point in their lives (using the older DSM-IV criteria), and risk was higher after interpersonal and sexual violence.10,11 Not meeting criteria for PTSD does not mean an experience left no mark, and these figures do not include distressing symptoms that fall below the threshold for a diagnosis.

Adults who report at least one potentially traumatic event

About 7 in 10

Of them, people who had PTSD at some point

5.6%

WHO World Mental Health Surveys.9,10

Research consistently links support from others after a traumatic event with a lower risk of lasting PTSD, and how the event was experienced at the time also matters. These are associations, and they do not show that support prevents PTSD.12,13

How often and how long

Single-event and repeated trauma

An early clinical framework, built from work with children, separated trauma from a single, sudden event from trauma that is long-standing or repeated, and noted that the two can overlap.14 US guidance describes trauma as a one-time event, several events, or something that went on for a long time, and notes that repeated trauma can affect people in ways that PTSD criteria do not fully capture.15

Single event

A car accident, an assault or a disaster

Repeated or long-standing

Ongoing abuse, violence at home, or living through war

Complex trauma

The idea of complex trauma was developed in the early 1990s to describe the effects of repeated trauma in situations that were hard to escape, including within families and close relationships.16 Today the term usually describes repeated harm, most often between people and often beginning in childhood, which may have broad and long-term effects.17

When the harm came from a caregiver, it can affect how safe closeness feels later.17 In adult life this may show up in relationships, in how a person sees themself, or in how hard it is to settle after stress. Complex trauma is a clinical description. The related diagnosis is Complex PTSD in the ICD-11.

Developmental trauma

Some researchers have proposed a diagnosis called developmental trauma disorder to describe the effects of repeated harm and disrupted caregiving early in life.18,19 It is not part of the DSM-5 or its 2022 text revision, and research on it continues, much of it from the group that proposed it.5,20

Where the harm came from

Relational and betrayal trauma

Relational trauma is a plain-language term for harm within close relationships, not a formal diagnosis. Betrayal trauma describes harm from a person or institution someone depends on, such as a caregiver, a partner, a school or a workplace, and this can make trust in later relationships harder.21

In international surveys, the risk of PTSD was highest after interpersonal violence, especially sexual violence.9,11 If you are experiencing violence at home now, your safety comes first. The note at the end of this page says where to turn in an emergency.

Collective and intergenerational trauma

When war, disaster or mass violence affects a whole community, researchers describe a collective trauma that can shape shared memory and identity, sometimes across generations. It is a social concept.22 A national survey in Lebanon found that exposure to war was linked with higher odds of later anxiety and mood disorders.23 In Palestine, a systematic review of 28 studies from Gaza and the West Bank, published up to 2020, estimated that about 36% of children and adolescents exposed to political violence met criteria for PTSD, with wide variation between studies and lower estimates in the more rigorous ones. The authors noted how hard it is to measure PTSD where harm is continuous and cumulative.38

Research on the children of survivors has found differences in how some of them respond to stress, and family and parenting experiences are one likely pathway. Researchers are studying whether biological changes play a part, but in humans this has not been established.24

Repeated experiences of racism or discrimination can leave stress reactions similar to trauma. Researchers call this racial trauma or race-based traumatic stress.25,26 It is not a formal diagnosis, and most of the research comes from the United States.

Medical trauma

Frightening medical experiences can be followed by post-traumatic stress symptoms for some people. In a review of studies of people who had a heart attack or a related acute heart condition, about 1 in 25 met PTSD criteria in a clinical interview, and about 1 in 6 reported significant symptoms on questionnaires.27

Secondary and vicarious trauma

People who hear about or see trauma through their work, such as therapists, health workers and first responders, can develop stress reactions of their own. This is sometimes called secondary traumatic stress or vicarious traumatization.28,29

Childhood adversity and smaller experiences

Adverse childhood experiences

A large 1998 study at a California health plan found that adults who reported more types of childhood adversity, such as abuse or serious difficulties in the household, were as a group more likely to report later health problems.30 US national survey data from 2011 to 2020 found that about 64% of adults reported at least one adverse childhood experience and about 17% reported four or more.31 Studies in Saudi Arabia using an Arabic version of the World Health Organization's childhood adversity questionnaire found the same pattern: more types of adversity went together with more health and mental health difficulties in adulthood.32,33

At least one adverse childhood experience

About 64%

Four or more

About 17%

US adults, national survey data from 2011 to 2020.31

These are patterns across groups. The ACE score was designed to study populations, and research shows it does not accurately identify which individuals will develop health problems.34 A score is not a diagnosis, and it does not measure what helped a person cope.

The questionnaire itself lists 10 categories of experience before the age of 18, and a score is the number of categories a person ticks. It was written for screening in health care, where the answers are gone through with a clinician, and it does not ask how severe an experience was or how long it lasted. The California Surgeon General’s Clinical Advisory Committee publishes the adult form in English and in Arabic.35

“Big T” and “little t” trauma

Some therapists, particularly in EMDR training, informally separate large events such as assault or disaster from smaller experiences such as being teased by peers or put down by a parent, which can still leave a lasting mark.36 This is a teaching shorthand, not a diagnosis.

One population study in the Netherlands found that stressful life events such as divorce or job loss were followed by post-traumatic stress symptoms at least as strong as those after events usually classed as traumatic.37 It measured symptoms, not diagnoses, and it is a single study.

Limits and support

The limits of what we know so far

Most of the research on this page comes from the United States, Europe and other Western countries. Studies from Saudi Arabia, Lebanon and Palestine are included where they exist. We did not find comparable studies from other Gulf countries. Surveys also depend on what people choose to report, and stigma may affect that in any country.

Support at True Self Practice

Knowing the name for an experience does not by itself decide what help fits it. Therapy usually begins with an assessment of your history, what is happening now and what you want from therapy, and the pace is agreed together. Depending on what you need, the work may draw on EMDR, Internal Family Systems (IFS), attachment-focused therapy or a polyvagal-informed perspective. This perspective is a way of thinking we draw on in sessions, not a stand-alone trauma treatment with established evidence. Sessions are online, in Arabic or English, depending on where you live and on each therapist's licensure.

This page is for education and is not a substitute for psychotherapy or a diagnosis. If you are in danger, or thinking about harming yourself, contact your local emergency number now. In the United States, you can call or text 988.

Frequently Asked Questions

Frequently asked questions about types of trauma

Clinicians often describe single-event trauma, repeated trauma, complex trauma, developmental trauma, relational or betrayal trauma, collective trauma, medical trauma and secondary trauma. Most of these are descriptions rather than diagnoses. PTSD is a diagnosis in both the US DSM-5-TR and the WHO's ICD-11, and Complex PTSD is a diagnosis in the ICD-11.

In the WHO's ICD-11, Complex PTSD combines the core symptoms of PTSD with ongoing difficulty regulating emotions, a deeply negative view of oneself, and difficulty feeling close to others. It most often follows prolonged or repeated trauma that was hard to escape. The US DSM-5-TR does not include Complex PTSD as a separate diagnosis.

Complex trauma usually describes repeated harm, most often between people and often beginning in childhood, which may have broad and long-term effects. It is a clinical description rather than a diagnosis. When the harm came from a caregiver, it can affect how safe closeness feels in adult relationships.

A PTSD diagnosis requires a specific kind of event, but outside diagnosis trauma is described more broadly, and the same event can affect people differently. One Dutch study found post-traumatic stress symptoms after life events such as divorce or job loss that were at least as strong as after events usually classed as traumatic.

International surveys find that most people who go through a potentially traumatic event do not develop PTSD, and that risk is higher after interpersonal and sexual violence. Not meeting criteria for PTSD does not mean an experience left no mark.

The ACE score was designed to study patterns across populations. Research shows it does not accurately identify which individuals will develop health problems, and it does not measure what helped a person cope.

Research on the children of survivors has found differences in how some of them respond to stress, and family and parenting experiences are one likely pathway. Whether biological changes play a part is being studied, but in humans this has not been established.

References

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  3. Shoval-Zuckerman, Y., & Horesh, D. (2025). The DSM-5 exclusion of media exposure to traumatic events: A critical reexamination in light of the October 7, 2023, attacks. Psychological Trauma: Theory, Research, Practice, and Policy, 17(7), 1548–1550. https://doi.org/10.1037/tra0002013
  4. Substance Abuse and Mental Health Services Administration. (2016). Impact of the DSM-IV to DSM-5 changes on the National Survey on Drug Use and Health. https://www.ncbi.nlm.nih.gov/books/NBK519704/
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