Supplementary Material for: Enhanced Skills Training in Affective and Interpersonal Regulation (ESTAIR) vs. Treatment as Usual (TAU) for ICD-11 Complex PTSD: A pilot randomised controlled trial (The RESTORE trial)

Introduction Complex PTSD (CPTSD) is a relatively new condition in ICD-11. This pilot randomised controlled trial aimed to compare a four-module intervention developed to target all symptoms of ICD-11 CPTSD, namely Enhanced Skills in Affective and Interpersonal Regulation (ESTAIR) with treatment as usual (TAU). The purpose of the study was to assess feasibility, safety, acceptability and preliminary outcomes at the end of treatment and 3-month follow-up. Methods A total of N=56 eligible veterans with CPTSD were randomised to either ESTAIR (n=28) or Treatment as Usual (TAU, n=28). Linear mixed models were conducted to assess CPTSD severity, the primary outcome, as measured by the International Trauma Questionnaire (ITQ). Results Treatment dropout in ESTAIR and TAU was low and equivalent (18% vs. 11%; 2 (1) = 1.19, p = .275), and study retention was high, supporting the feasibility of the study. No serious adverse effects and very few adverse effects occurred, none of which were deemed related to the study. ESTAIR provided significantly greater reduction in CPTSD severity across time for ITQ PTSD (p < .001) and DSO (p < .001) symptoms. CPTSD pre-to-post effect sizes for ESTAIR were large (PTSD d = 1.78; DSO d = 2.00). Remission of probable CPTSD diagnosis at post-treatment was substantially greater in ESTAIR compared to TAU with only 13.6% versus 84% (p < .001) retaining the diagnosis. Conclusion A trial of ESTAIR vs. TAU for the treatment of ICD-11 CPTSD indicates the potential efficacy of ESTAIR as well as its feasibility, safety, and acceptability.