What happens in an EMDR session, stage by stage

EMDR stands for eye movement desensitisation and reprocessing. It is a therapy for memories that still feel as though they are happening now.

The American psychologist Francine Shapiro developed it in the late 1980s.

NICE, which sets treatment guidance for the NHS in England, lists it among the recommended treatments for post-traumatic stress disorder in adults.

If all you have heard is "the eye movement thing", you have heard about one stage out of eight. The stages run in a fixed order, and I will take them in that order.

The first two stages are talking

Your first hour with me is mostly talking.

I take a history: what brings you, what you remember, what still catches you out, what you want to be different. Many people tell me afterwards it was the first time they had laid the whole timeline out in order.

Most people come in braced to describe the worst thing in full. I ask for the headline instead, one line on what the memory is about.

A few words about the memory are enough for me to work with. The detail can stay with you.

Then comes preparation. I explain how the sets work, agree a signal for stopping, and teach you ways to settle yourself, so you have them before I ask you to bring anything up. You stay awake throughout. People nearly always expect to be put under, and are surprised by how much it feels like an ordinary conversation.

I would rather you used the stop signal early than sat through something you did not need to. Most people use it less than they expect to, but knowing it is there changes how the first set feels.

Choosing the memory, then the movements

Next I ask you to choose a target. It is usually the earliest memory linked to the problem, or the worst recent one.

Then I ask for the worst image from it, or the moment that stands out. I ask for the sentence about yourself that goes with it, in the present tense: "I am in danger", "I cannot trust myself". I ask where you feel it in your body. And I ask for a number from 0 to 10 for how disturbing it is right now.

People can usually point to the spot in the body faster than they can find the sentence. The sentence tends to be old and flat, something carried so long it has stopped being heard. Saying it aloud is often the first time anyone has heard how it sounds.

Now the part you have heard of.

I ask you to hold the image, the sentence and the feeling in mind, and to follow my hand with your eyes as I move it from side to side. Taps or alternating sounds work for people who prefer them. Each set is short.

Then I stop and ask what you noticed. A word is enough, or a sentence, or "nothing much". I ask you to go with whatever it was, and I start another set.

The pause between sets is where most of the surprises happen.

People often find their mind has gone to a different memory, one that is connected, or to something that looks unrelated. The picture often moves further away or loses its colour.

Some people tell me very little has happened, and then give me a lower number.

Sets continue until the number comes down or the time runs out. Sometimes it falls to zero. Sometimes it moves part of the way, and that is where the session stops.

A session often runs sixty to ninety minutes.

You stay awake and in control throughout, and you can stop at any point.

How a session ends, and what comes after

When the memory pulls less, I go back to the sentence you gave me and ask what you would rather believe, something like "it is over" or "I am safe now". I ask how true that feels, then run short sets while you hold it beside the memory. That stage is called installation.

Next comes a body scan. I ask you to hold the memory and the new sentence together and notice your body from head to feet. Any tightness that is left gets another set.

Every session ends with settling, whether or not the memory is finished.

I use the last stretch to bring you back to the room and the present, and I tell you what to expect. Some people feel tired, dream vividly or feel stirred up for a day or two afterwards. I would rather you knew that in advance.

At the next session I begin by checking what has held. I ask you to bring the memory up again and give me the number, and what has shifted decides where the work goes next.

Over the whole course the order is usually the same: the earliest linked memory or the worst recent one, then the things in the present that set it off, then how you want to handle similar situations in future.

How many sessions that takes depends on your history. Studies of single-event trauma tend to show good results in a modest number of sessions.

Long histories take longer, and I will give you no figure before I have heard yours.

Nobody has a settled account of why it works.

One leading idea is that holding a memory while the movement also takes up some of your attention makes the memory less vivid. Another links it to how memories are processed in sleep. The evidence that EMDR helps in PTSD is stronger than the evidence for either explanation.