Objective: This study examined (1) how therapeutic alliance develops during intensive trauma-focused treatment with therapist rotation, (2) its bidirectional relationship with PTSD symptom change, and (3) exploratory associations between baseline patient characteristics, preferences, alliance ruptures, and perceived relational fit experiences with outcomes.

Method: Data were derived from 133 patients (75.8% female, mean age = 41.32 years, SD = 12.59) who received a 4-day intensive trauma-focused treatment combining prolonged exposure and EMDR therapy, delivered by rotating therapists. The PTSD Checklist for DSM-5 (PCL-5; intake, start day 2, mid-, post-treatment) and Working Alliance Inventory-Short Form (WAI-SF; start day 2, mid-, post-treatment) were administered. Linear mixed models and regression analyses were performed.

Results: Therapeutic alliance increased significantly from the start of day 2 to mid-treatment (d = 0.19) and then stabilised. Higher prior PTSD severity predicted lower subsequent alliance, while stronger prior alliance predicted greater symptom reduction, indicating a small bidirectional relationship. Exploratory analyses showed no significant associations between baseline PTSD severity, childhood sexual abuse, paranoia, attachment style, autism, and alliance development. Patient preferences shifted towards rotating therapist teams but were unrelated to outcomes. Post-treatment, alliance ruptures and lack of a perceived relational fit were linked to lower alliance, and unresolved ruptures to higher PTSD symptoms.

Conclusions: A therapeutic alliance can be established in rotation-based trauma-focused treatment, with small but consistent links to symptom change. Exploratory findings should be interpreted cautiously, and controlled studies are needed to clarify the specific role of therapist rotation in treatment outcomes and therapeutic alliances.