EMDR has been shown in many studies that it can be highly effective also for complex PTSD, see eg. a recent meta-meta-study ( https://doi.org/10.1016/j.janxdis.2025.103017 ). It very much and more depends on the relationship with the therapist, and how they integrate EMDR in a "complete" therapy. EMDR is a technique that can be used in many ways, not a full-fledged form of therapy.