What Does the Research Show?
The research on EMDR is extensive. Over 30 randomised controlled trials have evaluated its effectiveness for PTSD specifically — a higher evidentiary bar than most psychological treatments meet.
Key Findings
- Large effect sizes — EMDR produces clinically meaningful symptom reduction in the majority of people who complete treatment
- Speed — EMDR often achieves results in fewer sessions than other evidence-based treatments for trauma
- Durability — gains are maintained at follow-up, typically 3–15 months post-treatment
- Breadth — effective not just for single-incident PTSD but for complex trauma, childhood abuse, and developmental trauma
A 2013 meta-analysis by Chen and colleagues found that EMDR produced significant reductions in PTSD symptoms compared to both waitlist controls and active treatment comparators. A WHO-commissioned review reached similar conclusions.
Effect sizes and what they mean
Effect size is the standard way researchers quantify how much a treatment works. An effect size of 0.2 is considered small, 0.5 medium, 0.8 large. EMDR meta-analyses consistently report effect sizes in the large range (0.9–1.5) compared to control conditions. To put this in context: most medications for depression have effect sizes of approximately 0.3.
Honest Limitations
No treatment works for everyone. Across trauma-focused therapies including EMDR, roughly 20–27% of people do not complete treatment, and among those who do, a meaningful minority retain some residual symptoms. We cover this in detail in Module 7.
The research also tells us less about complex presentations — dissociative disorders, severe complex PTSD, ongoing trauma — where standard EMDR protocols require significant modification. This program reflects that honestly.