Cost-effectiveness of massed versus spaced trauma-focused treatment as first-line treatment for post-traumatic stress disorder in adults with multiple trauma exposure: protocol for a single-blind non-inferiority randomised controlled trial.

Introduction: Post-traumatic stress disorder (PTSD) is a serious disorder that burdens individuals and society. The current standard of first-line treatment for PTSD is spaced trauma-focused treatment (S-TFT), involving weekly sessions. While effective, S-TFT may take relatively long to complete, especially in patients exposed to multiple potentially traumatic events (PTEs). Massed trauma-focused treatment (M-TFT), involving increased session frequency, potentially results in faster symptom reduction and restoration of quality of life, as well as in a reduction of societal costs. However, M-TFT is not recommended as first-line treatment. This paper describes the research protocol of a single-blind, multicentre randomised controlled trial (RCT) aimed at investigating: (1) the clinical and cost-effectiveness of M-TFT versus S-TFT in employed, multiply traumatised patients who seek first-line treatment for PTSD and (2) predictive and moderating factors related to treatment response.

Methods and analysis: 186 participants are recruited from five centres and will be included if they are ≥18 years old, meet criteria for a Diagnostic and Statistical Manual of Mental Disorders Fifth Edition PTSD diagnosis based on ≥two PTEs, seek treatment for the first time and are employed. Patients with specified comorbid disorders and insufficient Dutch language proficiency are excluded. Participants are randomised to 800 min of either M-TFT or S-TFT. M-TFT consists of two once-weekly preparatory sessions, 10 twice-daily sessions of prolonged exposure, eye movement desensitisation and reprocessing therapy for 2 weeks and two once-weekly closing sessions. S-TFT consists of weekly sessions of one of five evidence-based treatment interventions. Outcomes are assessed at baseline and at 7 weeks, 17 weeks, 6 months and 9 months after baseline. Primary outcomes are clinical effectiveness in terms of PTSD symptom severity and cost-effectiveness based on quality of life measures and societal costs. Data will be analysed with linear mixed models.

Ethics and dissemination: This study protocol was approved by the Medical Ethics Review Board of the Amsterdam University Medical Center (NL86057.018.24). Participants will provide informed consent before enrolment in the trial. Results will be published in peer-reviewed journals and will be released to clinicians, patient groups and the general community.

Trial registration number: This protocol is registered at Overview of Medical Research in the Netherlands (OMON; trial register number 56960) and ClinicalTrials.gov (NCT06700590).