Intensive Treatment Versus Standard Weekly Prolonged Exposure for Adults With Post-Traumatic Stress Disorder

The goal of this clinical trial is to compare a novel, massed treatment format of prolonged exposure to gold standard trauma focused cognitive behavioral therapy (weekly delivered prolonged exposure) for post-traumatic stress disorder.

The objective with this study is to investigate efficacy, mechanisms of change and cost effectiveness of intensive prolonged exposure (I-PE) in regular Swedish psychiatric care.

Adult patients with post-traumatic stress disorder will be randomly assigned to receive either gold standard prolonged exposure weekly for 15 weeks or 5 days of intensive treatment with the addition of three booster sessions dispersed 1, 2 and 4 weeks after completion of the massed treatment period.

PTSD is one of the most common psychiatric disorders and is strongly linked to subsequent psychiatric and medical problems. Trauma-focused cognitive behavioral therapy (CBT-T) such as prolonged exposure is an effective treatment for PTSD and is recommended in most clinical guidelines as first-line treatment. However, the treatment period often lasts 3-5 months, which is believed to be a contributing factor to the high dropout rate that has suggested to be a major factor to why a significant proportion of patients fail to demonstrate clinically significant symptom change. In response, more intensive treatment approaches i have been developed based on the notion that frequency of treatment sessions are a potential mechanism for retention. Preliminary research shows intensive trauma focused treatment (I-PE) to be as effective as when the treatment is delivered by weekly sessions, but with the advantage that the recovery rate is faster and the proportion of patients who drop out decreases.

Before this type of treatment can be offered in regular care in Sweden, it needs to be further evaluated. If I-PE would be found to effective, this project has the potential to be the first step towards implementation of a novel, superior and more cost-effective mode of treatment delivery for adults with PTSD in regular Swedish health care. The intensive treatment format has yet to be directly compared to gold-standard CBT-T, and that is what we propose to do in this trial.

The study is a single-blind, parallel-group superiority randomized controlled trial with 140 patients (70 per arm) will compare intensive prolonged exposure to gold standard weekly delivered prolonged exposure. The primary outcome is the blind-rater administered Clinician-Administered PTSD Scale for DSM-5 (CAPS-5).

Secondary outcomes are cost effectiveness, speed of response, response and remission rates, dropout rate, and negative effects. The investigators hypothesis that participants in the massed treatment format will improve faster than patients that receive weekly sessions, but for the rest of the secondary outcomes, the investigators have no directed hypotheses.

The trial will also be preregistered at the Open Science Framework.

Eligibility Criteria:
Inclusion Criteria:

* 18 years of age or above,
* Primary PTSD diagnosis
* Fluent in Swedish
* Sign informed consent
* Able to attend either I-PE or 15 weekly sessions of PE

Exclusion Criteria:

* Initiation or adjustment of any psychotropic medication within the last 4 weeks prior to commencement of treatment
* Serious mental health symptoms, such as mania, psychosis, alcohol, or substance use disorders or current suicide risk warranting immediate clinical attention
* Ongoing evidence-based trauma-focused psychological treatment
* Ongoing trauma-related threat (e.g. living with a violent spouse)