This dataset contains data collected for the RE-DEFINE European randomised controlled trial which aimed to evaluate the effectiveness and cost-effectiveness of Self-Help Plus (SH+), a group self-help intervention developed by the WHO to reduce distress. In this trial, SH+ was tested as a preventative intervention to lower the incidence of mental disorders in asylum seekers and refugees with psychological distress resettled in Europe. This prospective, multicentre, randomised, rater-blinded, parallel-group study followed participants over a period of 12 months. Six hundred asylum seekers and refugees screening positive on the General Health Questionnaire (≥3), but without a formal diagnosis of any mental disorders according to the Mini International Neuropsychiatric Interview, were randomly allocated to SH+ or to enhanced treatment-as-usual. The primary outcome was a lower incidence of mental disorders at 6 month follow-up. Secondary outcomes included the evaluation of psychological symptoms, functioning, well-being, treatment acceptability and indicators of intervention cost-effectiveness. The trial received ethical clearance from the local Ethics Committees of the participating sites, as well as from the WHO Ethics Committee. All participants provided informed consent before screening and before study inclusion (a two-step procedure).

The dataset is provided in form of an Excel spreadsheet containing all relevant variables to analyze the pre-specified outcomes of the European RE-DEFINE randomized controlled trial. A legend guiding the interpretation of labels for each variable is embedded in the Excel file. An XML file reporting metadata is also provided.

The RE-DEFINE project received funding from the European Union’s Horizon 2020 Research and Innovation programme Societal Challenges under Grant Agreement No 779255. All relevant information and material are available at: http://re-defineproject.eu/ The protocol of the trial was registered in advance at clinicaltrials.gov with the following registration number: NCT03571347. A full protocol was published as follows: Purgato M, Carswell K, Acarturk C, et al. Effectiveness and cost-effectiveness of Self-Help Plus (SH+) for preventing mental disorders in refugees and asylum seekers in Europe and Turkey: study protocols for two randomised controlled trials. BMJ Open 2019;9:e030259. doi:10.1136/ bmjopen-2019-030259.

The present dataset is not open-access. The re-use of data will be offered only upon motivated request, which will undergo the scrutiny of the RE-DEFINE General Assembly.