Prolonged exposure in routine outpatient care: a naturalistic study of feasibility, safety and effectiveness

Background: Prolonged Exposure (PE) is a first-line evidence-based treatment for Posttraumatic Stress Disorder (PTSD), with well-established efficacy in randomised controlled trials. However, its implementation in routine care remains limited, particularly in outpatient clinics where evidence-based psychotherapies are not widely adopted.Objective: This study aimed to evaluate the feasibility, safety and effectiveness of PE therapy delivered in a real-world outpatient setting.Method: Data were obtained from 95 adults diagnosed with PTSD using the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) who received PE in a French outpatient clinic. The sample was characterised by a mean age of 35.65 years (SD = 13.16), 76% women (n = 72), a mean CAPS-5 score of 38 (SD = 9.4), and 61% reporting sexual trauma as the index event. PTSD Checklist for DSM-5 (PCL-5) and Quick Inventory of Depressive Symptomatology - Self-Report (QIDS-16-SR) were assessed at intake, pre-treatment, post-treatment and three-month follow-up. Mean changes were estimated using a linear mixed-effects model.Results: Patients received an average of 8 sessions of PE (SD = 3.75). Scores consistent with probable remission (PCL-5 < 33) was observed in 75.53% of patients, and 79.78% demonstrated a clinically significant improvement (≥10-point reduction on the PCL-5). A large decrease in PTSD symptoms was observed from pre- to post-treatment (Δ = 25.57, d = 1.88, p < .001), and to 3-month follow-up (d = 2.17, p < .001), exceeding the small effect found during the waiting-list phase (d = 0.33, p = .01). Similar improvements were found for depressive symptoms. Only 1% of patients showed a reliable clinical symptom worsening (≥10-points increase on the PCL-5) and the dropout rate was 9.47% (fewer than eight sessions completed without remission).Conclusion: These findings suggest that PE may be feasibly and safely delivered in routine outpatient care and may be associated with substantial reductions in PTSD symptoms. They highlight the potential for successful Implementation of evidence-based trauma treatments in real-world clinical settings where structured psychotherapies are not yet widely integrated.