The development of transdiagnostic standardized measures of psychological distress have contributed to the development of practice-based evidence networks. The translation and validation of such measures cross culturally is important if such research is to be generalized across health care systems in different countries.
Translation of the Clinical Outcomes in Routine Evaluation-Outcome Measure (CORE-OM) from English into Icelandic was undertaken according to recommended protocols. The resulting instrument was evaluated for reliability and validity in three groups: patients undergoing psychological treatment in general practice (n = 289), psychiatric outpatients (n = 98) and student controls (n = 207). The Mini-International Neuropsychiatric Interview was administered to the clinical participants. They also completed the CORE-OM and the Beck depression and anxiety inventories before and after treatment. The transdiagnostic relationship between CORE-OM scores and scores on those diagnostic measures was assessed.
Good levels of validity, reliability and internal consistency were found for the CORE-OM and its domains and sensitivity to change over treatment shown. As anticipated, the risk domain had different characteristics than other domains. CORE-OM scores correlated strongly with both Beck Depression Inventory-Second edition and Beck Anxiety Inventory, particularly the problem domain.
The Icelandic translation of the CORE-OM is psychometrically sound and can be applied in Icelandic mental health studies as it has been in English speaking settings. Nevertheless, the validity of the Icelandic version of the CORE-OM needs to be further investigated in larger and more diverse samples.
The psychometric properties of the Icelandic version of the CORE-OM are comparable with the original English version. The results indicate transdiagnostic utility of the CORE-OM. The CORE-OM is a valuable instrument in outcome research on psychological treatment, specifically transdiagnostic treatment.