A mixed-methods service evaluation for group traumatic episode protocol (G-TEP) for clients with heterogeneous trauma histories in an NHS outpatient psychological therapist service

This service evaluation investigated the feasibility of group EMDR-based intervention G-TEP for clients with varied trauma histories (not from a shared traumatic event), reporting good clinical outcomes.

Resource Abstract

“Group traumatic episode protocol (G-TEP) is an eye movement desensitization and reprocessing (EMDR)-based group intervention typically used with populations exposed to a shared traumatic event. Although trauma-focused cognitive behavioral therapy (TF-CBT) and EMDR are recommended by NICE for post-traumatic stress disorder (PTSD), high service demand often results in long waiting times for individual therapy. Evidence for G-TEP in groups with heterogeneous trauma histories is limited. This service evaluation explored its use within an NHS mental health service, where clients present with a broad range of traumatic experiences. A mixed-methods approach was employed using the Clinical Outcomes in Routine Evaluation—Outcome Measure (CORE-OM) and the International Trauma Questionnaire (ITQ-18), alongside a qualitative feedback questionnaire. Of the 23 participants who provided pre- and post-data, 74% demonstrated reliable improvement on CORE-OM, and 39% met the criteria for recovery. On ITQ-18, 83% showed reliable improvement. Based on ITQ-18 diagnostic criteria, 87% (n = 20) met thresholds consistent with PTSD or complex PTSD (CPTSD) at baseline, reducing to 39% (n = 9) post-intervention. Among those who initially met diagnostic criteria, 55% no longer met criteria after the intervention. Thematic analysis of the feedback questionnaire identified 6 overarching themes: sense of connection through group experience, emotional safety and trust, validation and normalization of trauma responses, meaningful symptom change, G-TEP specific mechanisms (structured, contained, and nondisclosing processing), and role of the practitioner. This service evaluation suggests that G-TEP represents a feasible and acceptable intervention for clients with heterogeneous trauma histories in routine clinical practice, indicating potential clinical utility. However, findings are preliminary and should be interpreted cautiously given the absence of a control group and the small sample size.”

—Description from publisher

Resource Access

Open Access

Lofthouse, B., Tanner, L., Liskevich, M., Jenkins, S., & Lingard, R. (2026). A mixed-methods service evaluation for group traumatic episode protocol (G-TEP) for clients with heterogeneous trauma histories in an NHS outpatient psychological therapist service. Journal of EMDR Practice and Research, 20, Article 28. https://doi.org/10.34133/jemdr.0028