Psychology › Mental health & disorders › Anxiety disorders
Post-traumatic stress disorder (PTSD)
Named 1980· Condition or disorder
Well replicatedStrong, repeated evidence.
A condition in which a terrifying event keeps replaying in body and mind long after the danger has passed.
See it on the Psychology map →What it says
After war, assault, disaster or a serious accident, some people have flashbacks and nightmares, avoid reminders, feel numb or guilty, and stay on high alert for more than a month. Earlier generations called it shell shock or combat fatigue; Vietnam veterans' advocacy won it a name in DSM-III in 1980. Most people exposed to trauma recover; about 6 percent of US adults develop PTSD at some point. Trauma-focused therapies such as prolonged exposure and cognitive processing therapy are best supported.
Why it matters
It recognized that overwhelming events can injure the mind lastingly, changing care for veterans, assault survivors and first responders.
The evidence
Studies of veterans, including the Vietnam Era Twin Registry, population surveys, brain imaging of fear circuits, and controlled trials of therapy and SSRI medication.
Open questions
Why some people develop PTSD and others do not is only partly understood. The FDA declined to approve MDMA-assisted therapy in 2024, citing trial problems.
Connections (5)
▸Post-traumatic stress disorder (PTSD) is a long-term reaction to extreme Stress, cortisol and fight-or-flightWell replicated
The connection
PTSD develops when the normal fight-or-flight response to extreme danger fails to switch off. The fear memory stays vivid and easily triggered, keeping the person on alert. Oddly, many patients show lower, not higher, resting cortisol, suggesting the stress system is reset rather than simply overactive.
Who showed it and when
Rachel Yehuda's studies of Vietnam veterans and Holocaust survivors in New York from the early 1990s found the low-cortisol pattern.
The evidence
Trauma exposure is required by definition, and studies that follow soldiers and accident victims show stress-system changes and PTSD emerging after trauma.
Open questions
The cortisol findings are inconsistent across studies, and why the same trauma leaves most people recovered but some with PTSD is not understood.
▸Post-traumatic stress disorder (PTSD) was once classed among Anxiety disordersWell replicated
The connection
From 1980 until 2013 the DSM listed PTSD among the anxiety disorders, because fear, hyperarousal and avoidance are central. DSM-5 moved it to a new 'trauma- and stressor-related' chapter, since it requires a triggering event and many patients' main problems are guilt, shame, anger or numbness.
Who showed it and when
DSM-III (1980) placed PTSD with the anxiety disorders; the DSM-5 work group moved it in 2013.
The evidence
The change is documented in DSM-5; PTSD and anxiety disorders still share genes, fear circuitry and exposure-based treatments.
Open questions
Some researchers see the move as mostly administrative; whether PTSD is fundamentally a fear disorder or a disorder of memory is debated.
▸EMDR (eye movement desensitization) is used to treat Post-traumatic stress disorder (PTSD)Mixed evidence
The connection
EMDR was designed for trauma memories. The patient recalls the worst image of an event, with its negative belief and body sensations, while tracking side-to-side movements, until the memory feels less upsetting and a positive belief replaces the negative one. It is used with veterans, assault survivors and disaster victims.
Who showed it and when
Francine Shapiro's first study (1989) treated trauma survivors, including Vietnam veterans; the WHO recommended EMDR for PTSD in 2013, as do US veterans' guidelines.
How solid is it?
Meta-analyses find it reduces PTSD symptoms about as much as trauma-focused CBT, but the American Psychological Association's 2017 guideline gives it only a conditional recommendation.
Open questions
Study quality varies and some trials were run by EMDR advocates; critics ask whether it works for reasons other than those its founder proposed.
▸Exposure therapy is a first-line treatment for Post-traumatic stress disorder (PTSD)Well replicated
The connection
PTSD is kept going by avoiding reminders. In prolonged exposure, patients repeatedly retell the trauma aloud, listen to recordings of it, and gradually revisit safe places they have avoided. This teaches that the memory is painful but not dangerous, and flashbacks, alarm and avoidance usually ease.
Who showed it and when
Edna Foa developed prolonged exposure in Philadelphia in the late 1980s and 1990s, first testing it with sexual assault survivors.
The evidence
Dozens of randomized trials support it; the American Psychological Association's 2017 guideline strongly recommends it, and the US VA has trained thousands of clinicians in it.
Open questions
Dropout is relatively high; researchers are testing whether shorter, intensive formats or added medication can make it easier to complete.
▸Psychedelic-assisted therapy (psilocybin, MDMA) was denied FDA approval for Post-traumatic stress disorder (PTSD)Well replicated
The connection
MDMA-assisted therapy for PTSD reached late-stage trials reporting large improvements, and the FDA granted it 'breakthrough' status in 2017. But in August 2024 the FDA declined to approve it and asked for another trial, after an advisory panel voted against it over blinding, data quality and safety concerns.
Who showed it and when
Sponsored by the nonprofit MAPS and its spin-off Lykos Therapeutics; Phase 3 trials 2018–2022; advisory panel vote June 2024; rejection August 2024.
The evidence
FDA and advisory committee records are public; the Phase 3 results appeared in Nature Medicine (2021, 2023), and Psychopharmacology retracted three earlier MDMA papers in 2024.
Open questions
Whether MDMA itself or expectation drove results, since most patients guessed their group; misconduct at one trial site deepened doubts. Supporters plan new trials.