Treating posttraumatic nightmares in trauma-affected refugees: An investigation of outcome predictors of imagery rehearsal therapy

A recent randomized controlled trial (RCT) did not find an effect of imagery rehearsal therapy (IRT) for nightmares as an add-on to treatment as usual in a sample of trauma-affected refugees. However, certain factors may have accounted for substantial variations in treatment outcomes. This study aimed to test whether symptom severity, cognitive functioning, use of an interpreter, motivation for psychotherapy, chronicity of posttraumatic stress disorder (PTSD), and variables relating to treatment participation predicted outcome for refugees receiving IRT as an add-on to treatment as usual. Data were derived from a pragmatic RCT, and those randomized to and who started IRT were included (N = 62). Outcome variables were pre-to post-treatment changes in sleep quality, nightmare severity, and PTSD symptoms. Multiple regression analyses revealed that higher baseline scores (more symptoms) were associated with treatment improvement across all outcome measures (βs = 0.32, 0.45, 0.44, ps = 0.007, 0.003, <0.001, respectively), while high motivation for psychotherapy predicted improvement in sleep quality (β = 0.28, p = .035) and PTSD symptoms (β = 0.28, p = .008). Additionally, lower cognitive functioning and use of an interpreter were associated with less treatment response on PTSD symptoms (β = -0.38, p = .002) and sleep quality (β = -0.28, p = .034), respectively. Findings indicate that low motivation and low cognitive functioning may represent modifiable barriers to refugees' ability to respond to IRT. The small sample may have affected the results, and future studies should use larger samples to improve reliability and generalizability.