Evaluation of the psychometric properties of the Icelandic version of the Clinical Outcomes in Routine Evaluation-Outcome Measure, its transdiagnostic utility and cross-cultural validation

Background: 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.

Method: 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.

Results: 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.

Conclusion: 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.

Key practitioner message: 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.