The study will investigate the research questions in three stages. In the first stage four patients will be treated individually. In the second stage two groups of four patients will be treated, with at least a 1:1 ratio between therapists and patients per group. In the third stage 30 patients will be treated in groups of about four patients per group, with at least a 1:1 ratio between therapists and patients per group. The primary outcome measure is changes in PTSD-related symptoms as measured using the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). Acceptability will be measured as the proportion of patients accepting treatment when offered, while attrition is measured as the proportion of patients that withdraw from treatment after it has started. Several other measures will be collected to measure treatment satisfaction, related symptoms, and functional impairment.
