EMDR is a completely different approach to therapy than most people imagine. Rather than talk through a person’s problems, EMDR – eye movement desensitization and reprocessing – takes the approach that a traumatic event or events get “stuck” in the brain causing a person to experience their emotions and memories like they’re currently happening, and through a series of rhythmic movements and guided conversation it can be unstuck and move to long term processing where it becomes much less emotionally charged.
It sounds like science fiction, yet it is now considered one of the most effective and widely recognized treatments in the field of psychotherapy.
Still, while we have a general understanding of how it works, we do not truly understand all of it.
There’s a theory about why EMDR works that most people have never heard of before, but could make sense as a possible reason that EMDR is effective, and it relates to dreams.
REM Sleep and Rapid Eye Movements
Every night while you sleep, your brain is quietly doing something your waking mind can’t. During REM sleep — the stage when you dream — your eyes move rapidly back and forth beneath your eyelids. For a long time, researchers figured this was just a side effect of dreaming, something happening in the background without much meaning.
But it’s likely more than that.
What Your Brain May Be Doing While You Sleep
REM sleep is strongly associated with emotional memory processing — and researchers believe it may be one of the primary ways the brain works through the emotional weight of experience. During this stage, memories appear to get consolidated and reorganized. The emotional intensity attached to them tends to soften over time.
It’s a plausible explanation for something most people have noticed: a difficult conversation that felt crushing the night before can feel more manageable in the morning. Sleep researchers have proposed that what’s happening during REM is part of why.
The evidence for this is meaningful and taken seriously in the field — but like much of what we understand about the sleeping brain, the full picture is still being filled in. What does appear consistently in the research is that REM sleep and emotional regulation are connected in ways that go well beyond simple rest.
What Happens When that System Breaks Down?
For most experiences, even hard ones, this works well enough. The memory gets processed, the intensity fades, and you move forward.
Trauma is different.
When something happens that is too overwhelming for the brain to handle in the moment, the normal processing system breaks down. The memory doesn’t get filed the way ordinary memories do. It stays raw. It keeps its full emotional and sensory intensity — the sounds, the images, the physical feelings — all of it preserved exactly as it was in the moment it happened.
This is why traumatic memories don’t behave like regular memories. They don’t fade with time. They intrude into the present without warning. The brain keeps circling back to them as though trying to finish something it never got to complete — because neurologically, it didn’t. The experiences got stuck, and so too does the emotional weight with them.
For experiences that were overwhelming enough, the brain’s natural nightly processing simply isn’t sufficient. Whatever mechanism REM sleep uses to work through everyday stress and difficulty doesn’t seem to reach what got left behind after genuine trauma.
Where EMDR Comes In
Nobody knows exactly why EMDR works. We know it does, and we know that we can measure that it’s working, but scientists are still unclear the exact neurological mechanism that allows it to be effective.
The REM sleep hypothesis is one of the most compelling ideas on the table. The bilateral eye movements used in EMDR — following the therapist’s moving fingers back and forth while holding a distressing memory in mind — look similar to the rapid eye movements that happen during REM sleep. Some researchers have proposed that this resemblance isn’t coincidental, and that the bilateral stimulation may be engaging the same processing system the brain uses during dreaming.
If that’s true, EMDR isn’t doing something foreign to the brain. It’s replicating something the brain already knows how to do — running a traumatic memory through a process that should have happened naturally but didn’t.
It’s a fascinating theory, and researchers take it seriously. But it remains a hypothesis. The evidence for it is suggestive rather than conclusive, and other explanations have meaningful research behind them too.
One competing theory — the working memory hypothesis — proposes something different entirely. It suggests that the bilateral stimulation works by occupying part of the brain’s working memory capacity at the same time as the traumatic memory is being held in mind. Because working memory has limits, the stimulation effectively competes with the memory for cognitive resources, reducing its vividness and emotional intensity in the process. Some of the more controlled experimental research actually supports this explanation more directly than it supports the REM sleep parallel.
These theories don’t necessarily cancel each other out. They may be capturing different aspects of the same underlying process, or both may be partially correct. The honest position is that researchers are still working it out.
What can be said with more confidence is that the bilateral stimulation component of EMDR produces measurable effects — and that those effects appear to be specific to the stimulation itself, not just other elements of the therapy. Studies that have compared EMDR with and without the eye movement component generally find that the eye movements matter. Brain imaging research has shown real changes in how the brain responds to traumatic memories after EMDR treatment — the emotional response quiets, and the memory begins to behave more like an ordinary one.
Why exactly that happens is still an open question. That it happens is not.
What People Actually Experience
Whatever the mechanism turns out to be, what clients describe after EMDR processing is consistent enough to be worth paying attention to.
Talk therapy is valuable — it builds insight, context, and understanding around what happened. But talking about a traumatic memory doesn’t always change how it feels. A person can understand intellectually why something affected them the way it did and still find the memory just as distressing to encounter. The understanding and the emotional charge can exist completely independently of each other.
EMDR tends to produce a different kind of shift. After processing, clients often describe the memory as simply feeling different — quieter, more distant, less charged. Not forgotten, and not rewritten, but no longer carrying the same weight it did before.
Whether that’s because the brain completed something similar to REM sleep processing, or because working memory interference reduced the memory’s intensity, or because of something researchers haven’t fully mapped yet — the outcome is the same. The memory stops feeling like a current threat and starts feeling like the past.
For people who have carried traumatic experiences for years without that shift happening on its own, that change can be significant.
The Bigger Picture
What makes EMDR genuinely interesting — scientifically, not just clinically — is that it produces reliable results through a mechanism that isn’t fully understood. That’s unusual in mental health treatment, where therapies are typically built on fairly well-established theoretical frameworks.
It also raises questions worth sitting with. If the REM sleep hypothesis is correct, it suggests that the brain has a built-in system for healing from trauma that can be deliberately engaged. If the working memory hypothesis is correct, it suggests that the intensity of traumatic memories is more malleable than it feels — that the right kind of cognitive load can reduce what seemed immovable.
Either way, the evidence points toward the same conclusion: that trauma doesn’t have to stay the way it is. The brain has more capacity for change than most people who are living with trauma have been led to believe.
Finding Out If EMDR Is Right for You
Flourish Psychology offers EMDR therapy in Brooklyn for adults working through trauma, PTSD, anxiety, and related experiences. If you’ve been carrying something that hasn’t shifted through talk therapy alone, it may be worth exploring whether EMDR can reach what other approaches haven’t.
Reach out through the contact page or call 917-737-9475 to get started.