EMDR for PTSD: How It Works, What the Evidence Says and Who It Helps

1 November 2026

EMDR is one of two psychological treatments that the UK's National Institute for Health and Care Excellence (NICE) recommends for adults with post-traumatic stress disorder. The other is trauma-focused cognitive behavioural therapy. Both have a solid research base, and recent UK reviews find little difference between them in how well they work. This guide explains what PTSD is, how EMDR therapy works on traumatic memories, what the research says and where it is still thin, and how to judge whether this approach is likely to suit you.

What post-traumatic stress disorder is

Post-traumatic stress disorder can develop after a frightening, threatening or horrifying event, or a series of them. In ICD-11, the World Health Organization's diagnostic system, it has three core groups of symptoms:

Re-experiencing the event in the present. Flashbacks, nightmares or intrusive memories that feel as if it is happening now, not like ordinary remembering.
Avoidance. Steering clear of places, people, conversations or thoughts that bring it back.
A persistent sense of current threat. Hypervigilance, a strong startle reaction, poor sleep and feeling on edge long after the danger has passed.

The complex form has those core symptoms plus lasting difficulties in three further areas. These are managing emotions, a deep sense of being worthless, ashamed or a failure, and difficulty feeling close to others. It is more often linked to repeated or prolonged trauma, such as childhood abuse, domestic abuse, or years of exposure to distressing events at work.

The condition is more common than many realise. The most recent Adult Psychiatric Morbidity Survey, carried out in 2023 and 2024, found that 5.7% of adults in England screened positive for it. The survey found 4.4% in 2014, but does not treat the difference as a real increase. Rates are far higher in some groups. In a 2018 survey of almost 17,000 UK police officers and staff, around one in five of those exposed to trauma reported symptoms of some form of PTSD.

How EMDR works on traumatic memories

EMDR stands for eye movement desensitisation and reprocessing. It was developed by the American psychologist Francine Shapiro in the late 1980s.

The theory behind it, the adaptive information processing model, holds that most experiences are processed and filed away as ordinary memories. A traumatic memory can get stuck instead. It stays stored with the images, sounds, body sensations and beliefs from the moment it happened, which is why a smell or a sound can bring it back with full force years later. The therapy aims to help the brain finish processing the memory, so that it can be remembered without being relived.

During the processing phases, you hold part of the memory in mind while following the therapist's hand or a light bar with your eyes. Other forms of bilateral stimulation work too, such as alternating taps on the hands or sounds through headphones. After each short set, you notice what has come up and say a few words about it, and the therapist guides the next set. Over a session the memory usually becomes less vivid and less distressing, and the beliefs attached to it often shift. "I'm in danger" can become "it's over", or "it was my fault" can become "I did what I could".

How the eye movements help is still debated, and this is one reason the method has a reputation for being controversial. The most studied explanation is the working memory account. Holding a memory in mind while doing a demanding task at the same time seems to make the memory less vivid and less emotional. Some researchers argue the eye movements add little beyond the exposure to the memory itself. What is not seriously disputed is that the therapy as a whole works for this condition, which is why NICE and the World Health Organization both recommend it.

The eight phases of treatment

The therapy follows a set structure:

History taking. Your background, what you want help with, and the memories that may need work.
Preparation. Explaining the process, and building ways to steady yourself, such as a calm place exercise or a mental container for distressing material.
Assessment. Choosing the target memory, the image, the negative belief, the emotion and where you feel it in your body, with ratings of how disturbing it feels.
Desensitisation. Processing the memory with sets of bilateral stimulation until it feels much less disturbing.
Installation. Strengthening a more helpful belief about yourself.
Body scan. Checking for any remaining tension linked to the memory.
Closure. Ending each session steady, whether or not the memory is finished.
Re-evaluation. Reviewing progress at the start of the next session.

The early phases matter as much as the processing. A good therapist will not start processing until you have reliable ways of calming yourself. What is the EMDR therapy process? explains each phase in more detail, and a therapy session example follows one session from start to finish.

What the evidence says

What NICE recommends

The NICE guideline on post-traumatic stress disorder, NG116, recommends offering EMDR to adults with the condition, or clinically important symptoms, who come for help more than three months after a trauma outside military combat. It suggests considering it between one and three months after a trauma if the person prefers it. Treatment should typically run over 8 to 12 sessions, with more where it is clinically needed, for example after multiple traumas. For the first month after a traumatic event, NICE favours trauma-focused CBT for those with acute stress disorder or significant symptoms, and active monitoring for milder ones. It also says not to offer psychologically-focused debriefing to prevent the condition.

Recent UK research

A 2025 systematic review and meta-analysis by Simpson and colleagues at the University of Sheffield, published in the British Journal of Psychology, gathered the trials published since the NICE guideline. It found EMDR clearly better than waiting list or usual care, and no significant difference between it and trauma-focused cognitive behavioural therapy. Its courses tended to be shorter and to ask less of a client's time. In the one economic model available, it came out as the most cost-effective option. The authors also note that most of the trials were small and at moderate or high risk of bias, so the evidence is good but not flawless.

Real-world NHS figures point the same way. NHS England data for 2021 to 2022, reported by Belli and colleagues in 2025, showed a recovery rate of 45.9% across 5,083 completed courses of EMDR in NHS Talking Therapies, against 40.4% across 24,452 courses of CBT. Their own 11-year evaluation of one London service found recovery rates of 43.6% and 40.8% for the two therapies, with no significant difference between them. These are routine service figures rather than trials, and they count only those who finished treatment, but they show the therapy holding its own in ordinary NHS practice.

When the trauma is complex

The complex form of the condition can respond well, but the work usually takes longer. More time goes into the preparation phase, building the ability to stay steady with difficult feelings before memories are processed. There may be many memories to work through, and some of the work is about the beliefs and relationships that repeated trauma shapes, not the memories alone. The research here is less developed. In the UK, a study of police officers found that brief trauma therapy reduced symptoms, depression and anxiety in officers with the complex form as well as in those with the standard diagnosis, though it had no comparison group.

Is this the right therapy for you?

EMDR tends to suit those who:

can point to specific memories, or a set of them, that still feel raw
would rather not go over what happened in great detail, or set homework between sessions
want a structured approach with a clear focus

It may need adapting, or waiting for, if you are in crisis, unsafe at home, or dissociating heavily. In those situations a therapist will usually spend longer on stabilisation first. If you are drinking heavily or using drugs to cope, it helps to say so at the start, because it affects how the work is paced. PTSD and alcohol looks at this in more detail.

It is not the only good option. Trauma-focused CBT has similar evidence, and a comparison of the two sets out the differences. Some prefer a slower, relational approach that does not target memories at all, and person centred therapy for PTSD describes that route. If you're unsure, which is right for me? may help you decide.

How many sessions does it take?

It depends mainly on whether there is one traumatic memory or many. Recovery from a single incident in an adult with good support can sometimes take a handful of processing sessions. Repeated or long-standing trauma can take months. NICE's typical range of 8 to 12 sessions is a guide, not a limit. How many sessions are needed? and how long does the therapy take? go into what shapes the number. The therapy can also be delivered online, and can it be effective online? looks at the evidence.

High-risk occupations

Some occupations carry a much higher risk because of what the work involves, and the therapy is often adapted for them. EMDR for emergency services staff covers police officers, paramedics, firefighters and 999 control room staff, whose trauma tends to build up over years of calls rather than come from a single event.

Frequently asked questions

Is EMDR hypnosis?

No. You stay awake, aware and in control throughout, and you can stop at any point. You will remember the session afterwards.

Do you cry during EMDR?

Some do, and some don't. Strong feelings can come up during processing and then pass. Crying is not a sign that something has gone wrong, and it is not required for the therapy to work.

Can it make things worse?

Some feel more unsettled for a few days after a session, with vivid dreams, memories surfacing or tiredness. This is usually temporary. Careful preparation, and a therapist who closes each session properly, reduces the risk. Side effects and the EMDR hangover covers what to expect and when to raise concerns.

Does it erase memories?

No. You will still remember what happened. The aim is that the memory stops feeling as if it is happening now, and becomes something you can recall without being overwhelmed.

Is it available on the NHS?

In England, NHS Talking Therapies services offer it for post-traumatic stress in many areas, and you can usually refer yourself. Availability and waiting times vary from area to area. Many also see a private therapist, either because of waiting lists or because they want to choose who they work with.

Why is EMDR controversial?

Mostly because of the eye movements. Early claims about them were strong, and researchers still debate how much they add. The overall evidence that the therapy works is not in serious dispute, and it is recommended by NICE and the World Health Organization.

Therapy with me in Nottingham and online

I'm a BACP registered counsellor offering EMDR therapy and person centred counselling in Nottingham and online. If you think it might help, you can get in touch to talk it through before committing to anything.

If you are in crisis now, call 999, call NHS 111 and choose the mental health option, or call Samaritans free on 116 123.

Sources

More about EMDR therapy