What to Expect During and After EMDR Therapy

EMDR, or Eye Movement Desensitisation and Reprocessing, is a structured psychological therapy used particularly in the treatment of post-traumatic stress disorder (PTSD). NICE recommends EMDR for adults with PTSD or clinically important PTSD symptoms in specified circumstances, and states that it should be delivered by trained practitioners using a phased approach.

People often ask what they might notice during a session, whether it is normal to feel unsettled afterwards, and whether experiences such as tiredness, vivid dreams or increased emotions are part of EMDR.

The evidence is clearer about the effectiveness of EMDR for PTSD than it is about specific short-term reactions after individual sessions. This article explains what research and clinical guidance do support, and where the evidence is more limited.

You can also read more about EMDR therapy and how I work with it in my practice.

What happens during EMDR therapy?

NICE describes EMDR as a phased treatment that includes psychoeducation about reactions to trauma, managing distressing memories and situations, identifying and treating target memories, and developing more adaptive beliefs about the self.

During memory-processing phases, the person brings aspects of a distressing memory to mind while engaging in bilateral stimulation, usually eye movements. NICE also notes that other forms of bilateral stimulation, such as taps or tones, may be used where appropriate.

Because EMDR involves deliberately recalling distressing material, emotions and bodily reactions connected with the memory may become noticeable during a session. The aim is not to make someone as distressed as possible. Treatment should be paced and delivered within a structured protocol.

How might EMDR affect a distressing memory?

The exact mechanisms of EMDR are still being studied. One of the better supported explanations is the working-memory account.

Research suggests that recalling an emotional memory while carrying out a second task, such as eye movements, places competing demands on working memory. Laboratory studies and meta-analyses have found that this can reduce the vividness and emotional intensity of emotional memories.

This does not mean that the mechanism of EMDR has been fully established. A systematic review of proposed mechanisms concluded that the working-memory account has reasonable empirical support, while also noting that research into how EMDR works remains incomplete.

What can happen after an EMDR session?

This is an area where it is important to be precise.

There are many descriptions online of possible reactions after EMDR, including tiredness, vivid dreams, headaches, emotional sensitivity and memories coming to mind. However, high-quality research has not established a reliable list of common EMDR-specific after-effects or how frequently each one occurs.

A 2025 review examined 51 randomised controlled trials of EMDR for PTSD. Only nine of those studies mentioned adverse effects, and only one used a systematic method for assessing them. In five of the nine studies, participants did report adverse effects, which were generally described as mild and temporary. The authors concluded that adverse effects have been under-reported and insufficiently measured in EMDR research.

This means it would be misleading to present a long list of post-EMDR symptoms as though research has shown that everyone, or even most people, should expect them.

Is it normal to feel worse after EMDR?

EMDR involves working directly with distressing memories, so some degree of emotional discomfort during treatment is possible. NICE specifically states that EMDR should include support with managing distressing memories and situations.

What the research does not provide is a simple rule that feeling worse after a session is either expected or evidence that treatment is working.

If you notice a temporary increase in distress after a session, it is reasonable to discuss it with your therapist. If distress is substantial, persistent, difficult to manage or interferes with everyday functioning, your therapist should know. The pace, preparation and timing of further memory processing can then be reviewed.

How long do reactions after EMDR last?

There is not enough good-quality evidence to give a reliable time limit for post-session reactions.

The available EMDR research does not support statements such as “after-effects normally last 24 to 48 hours” as a general rule. People vary, sessions vary, and the research on adverse effects has not measured this consistently enough to establish a standard timeframe.

If something continues for longer than you expected, becomes more intense, or causes concern, speak to your therapist rather than assuming that it is simply part of the process.

Why might I feel tired after EMDR?

Some people describe feeling tired after emotionally demanding therapy. However, research has not established fatigue as a specific or predictable side effect of EMDR.

It is therefore better not to assume that tiredness must have been caused by EMDR. Sleep, stress, physical health, medication, work demands and many other factors can affect energy levels.

If tiredness is mild and short lived, it may simply be something to notice. If it is persistent, severe or unusual for you, it is sensible to consider other possible causes and seek appropriate medical advice if needed.

What about vivid dreams or memories coming to mind?

People sometimes report dreams, thoughts or memories relating to material discussed in therapy. However, there is not enough high-quality evidence to state how common this is specifically after EMDR.

If new material comes to mind between sessions, you do not need to analyse it or force yourself to continue processing it alone. You can make a brief note if that is helpful and discuss it at your next appointment.

If memories become intrusive, highly distressing or difficult to manage, contact your therapist sooner.

Physical sensations during or after EMDR

Emotional memories can be accompanied by bodily reactions such as changes in tension, breathing or arousal. These responses can become noticeable when distressing memories are recalled.

It is not accurate to describe this as trauma being literally stored in, released from or discharged from a particular part of the body. Current evidence does not support that explanation.

Physical symptoms can have many causes. New, severe or persistent physical symptoms should not automatically be attributed to therapy and may need assessment by an appropriate healthcare professional.

What should happen between EMDR sessions?

NICE guidance emphasises that EMDR should be delivered in a phased manner and should include preparation for managing distressing memories and situations. What this looks like should be agreed with your therapist and adapted to you.

Some people find it useful to keep a brief note of anything important that comes up between appointments. This might include a memory, a change in how a situation feels, a recurring thought or something you want to discuss at the next session.

There is no need to deliberately continue memory processing between sessions unless that has been specifically agreed as part of your treatment.

When should I contact my therapist?

Contact your therapist if you experience a marked increase in distress, feel unable to manage what has emerged, notice significant dissociation, or find that your usual functioning has become substantially more difficult.

EMDR should be collaborative. If treatment feels too intense, this is information that should be discussed rather than something you are expected to push through.

If you are at immediate risk of harming yourself or someone else, seek urgent help rather than waiting for your next therapy appointment. In the UK, call 999 or go to A&E in an emergency.

EMDR is not the same experience for everyone

There is no single correct response to EMDR. Some people notice clear emotional or cognitive changes after a session. Others notice very little between appointments.

The evidence supports EMDR as a treatment for PTSD, but it does not support the idea that a particular after-effect must occur for treatment to be effective.

Research on adverse effects is also less developed than research on treatment outcomes. That uncertainty matters. It is more accurate to acknowledge it than to give people a fixed checklist of what they are supposed to feel.

Considering EMDR therapy?

If you would like to understand more about the treatment itself, you can read my EMDR therapy page.

If you would like to discuss whether EMDR may be suitable for you, you can book a free consultation.

Sources and further reading

• NICE guideline NG116: Post-traumatic stress disorder.
• Matthijssen SJMA, et al. Adverse effects of Eye Movement Desensitization and Reprocessing therapy: A neglected but urgent area of inquiry. 2025.
• Landin-Romero R, et al. How Does Eye Movement Desensitization and Reprocessing Therapy Work? A Systematic Review on Suggested Mechanisms of Action. 2018.
• Mertens G, et al. The effectiveness of dual-task interventions for modulating emotional memories in the laboratory: A meta-analysis. 2021.
• Hoppen TH, Lindemann AS, Morina N. Safety of psychological interventions for adult post-traumatic stress disorder. British Journal of Psychiatry. 2022.