What exactly happens during EMDR therapy?
Written by the clinical team at The Lyceum Clinic. Clinically reviewed by Sanah Younis, Founder and Clinical Director, BABCP-accredited (no. 1000792). Published 28 October 2026. Last reviewed 28 October 2026.
Clinical perspective: The Lyceum's specialist therapist in EMDR.
What is EMDR doing?
Your brain is designed to heal psychological wounds exactly like your body heals physical ones. But trauma is like a piece of glass stuck in the wound. It halts the healing process. The memory gets locked in the nervous system with all the original sights, sounds, and terror. EMDR uses bilateral stimulation (eye movements or tapping) to kickstart the brain's Adaptive Information Processing system. We aren't deleting the memory; we are pulling the glass out so your brain can finally digest it and move it from 'present danger' to 'past history.'
What is the preparation phase, and why can it take more than one session?
Preparation (Phase 2) is building the brakes before we drive the car. We cannot open up a terrifying trauma box until I know you have the neurological tools to close it again. We install a 'Safe Place' and grounding techniques. If someone has complex trauma, this can take weeks. If we rush into processing without an anchor, the client will just re-traumatise themselves and dissociate.
For more detail, read about trauma-focused CBT.
What does a set actually feel like for the client?
Clients often expect to be hypnotised or to magically forget the event. Instead, during a set of eye movements, they describe feeling like they are on a fast-moving train looking out the window at the memory. The scenery changes rapidly. They often feel sudden, intense physical shifts, a tightening in the chest, a wave of heat, and then a profound, exhausting unclenching. It is a highly somatic experience.
What happens in the hours and days after EMDR?
I call it the 'EMDR Hangover.' Your brain will continue processing for 24 to 48 hours. It is completely normal to have vivid, bizarre dreams, sudden flashes of emotion, or profound fatigue. I tell clients: 'Do not plan a massive presentation or a heavy social event the evening after a session. Go home, drink water, watch terrible TV, and let your nervous system rest.'