Trauma treatment using Narrative Exposure Therapy adapted to persons with intellectual disabilities or severe chronic mental disorders - a randomised controlled pilot study with an embedded observational study.

Abstract

Despite an increased likelihood of experiencing traumatic events and increased vulnerability, there are only few publications on trauma therapy for persons with intellectual disabilities (IDs). This pilot study for the first time investigates the feasibility and effectiveness of Narrative Exposure Therapy (NET) within this target group modified by Plain Language. A group of n=10 participants with ID dual diagnoses and another group of n=5 participants with severe and chronic mental disorders were separately stratified and randomised, then forming together an intervention group (n=7) and a waiting list control group (n=8). All participants were treated with NET attuned to their communication abilities by using Plain Language. Primary outcome was the post-traumatic stress measured with the Post-Traumatic Symptom Scale-10 before and after the intervention. In addition, the Adverse Childhood Experience Index was used for diagnostic purposes. Data were analysed using t-test for repeated measures and analysis of covariance. Narrative Exposure Therapy and the randomised controlled trial study proved to be successfully conductible with participants with IDs in a congregated residential service. Although the corresponding effect size was high (partial eta square=0.188), the between-group difference was not significant (P=0.12). Analysis of the observational study resulted in a highly significant improvement for participants with IDs (P<0.001; Hedges' g=2.36) and in a significant improvement in participants with severe and chronic mental disorders (P<0.013; Hedges' g=1.52). Additionally, the participants with IDs show a significantly better reduction of symptom burden (P=0.03; partial eta square=0.327). The results provide a first evidence for a possible and successful implementation of NET modified in Plain Language for persons with IDs and complex mental health support needs. Completeness in responding to the items of Post-Traumatic Symptom Scale-10 and Adverse Childhood Experience Index indicates the suitability of these instruments for both groups of participants. Although the group difference in the randomised controlled trial failed to achieve statistical significance mainly due to the small sample size, the results of the embedded observational study are promising for the conduct of further studies with the modified NET.