PT-STRESS Study: Predicting Treatment Success and Dealing With Non-response in the Treatment of PTSD
The aim of this study is to increase understanding of the effectiveness and efficiency of psychological treatment for adult patients with posttraumatic stress disorder -PTSD- and to make it more personalized.

Key questions:

Which predictors of treatment success influence treatment outcome of patients with PTSD who receive the three psychotherapeutic treatments investigated in this study?
Which specific moderators can be identified with regard to the different psychotherapies (Eye Movement Desensitization and Reprocessing -EMDR-; Prolonged Exposure -PE-; and Interpersonal Psychotherapy -IPT- in the second phase)?
In patients with PTSD, does offering another proven effective form of trauma-focused psychotherapy (PE after EMDR, or EMDR after PE) improve symptoms following insufficient response to a first trauma-focused treatment?
Is switching from a trauma-focused therapy to a non-trauma-focused treatment (IPT) a more effective strategy for dealing with non-response to a first proven effective psychotherapeutic treatment compared to switching to another trauma-focused therapy?
Are there differences in treatment tolerance and differences in dropout rates between PE, EMDR and IPT?

Secondary goals:

Investigating the extent to which therapist allegiance to a specific therapy method affects outcomes;
Investigating whether the quality of therapy implementation or the treatment integrity ('adherence/ competence') affects treatment outcomes;
Investigating how much the quality of the therapeutic alliance influences outcomes.

Participants receive treatment and will complete questionnaires. The study is conducted in two phases. Its aim is to compare two different trauma-focused treatments (EMDR and PE) for patients with PTSD to one another and with a nontrauma-focused psychotherapy (IPT) and to investigate possible predictors and moderators for treatment success. Patients will first be randomized to PE or EMDR in the first treatment phase. After this first phase, non-responders are re-randomized for a second phase of treatment. They receive either the alternative phase 1 trauma-focused psychotherapy or IPT as non-trauma-focused therapy. In phase 1 researchers will compare the PE and EMDR group to see which treatment is most effective for whom. In phase 2 researchers will compare the trauma-focused treatments (PE and EMDR group) with the nontrauma-focused treatment (IPT group) to see which treatment is most effective for whom.
- EligibilityCriteria: Inclusion Criteria:  Adults between the ages of 18 and 65 who were classified with a primary diagnosis of PTSD (based on the DSM-5 criteria). Adults who are willing to participate in the study (informed consent)  Exclusion Criteria:  Insufficient proficiency in the Dutch language. Patients who cannot follow the treatment protocol (for example due to prolonged absence) are excluded from the study. Patients who use medication that is not stable. If properly set to the last prescribed medication by the doctor there will be advised to continue and referably not change the medication and its dose during treatment, unless necessary in connection with side effects, crisis, etc. Patients that already received an evidence-based form of trauma-oriented treatment for PTSD in the past year and for sufficient treatment duration, in accordance to the Dutch professional practice guidelines (reference: Akwa GGZ (2020, December 1). GGZ Standaarden. Psychotrauma- en stressorgerelateerde stoornissen. Retrieved September 29, 2022, from https://www.ggzstandaarden.nl/zorgstandaarden/psychotrauma-en-stressorgerelateerde-stoornissen/introductie). Patients with serious suicidality that requires acute intervention and structural addition of additional treatment interventions. Patients with an intellectual disability. Patients with a serious addiction as a comorbid problem. Patients with an acute mania or a psychotic state. - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - MaximumAge: 65 Years - StdAgeList: Adult, Older Adult