Mental Pain Questionnaire: Clinimetric Properties of a Potential Global Person‐Centred Outcome Measure

Introduction: The Mental Pain Questionnaire (MPQ) was developed using a clinimetric approach to bring together the key features of mental pain into a single, brief, transdiagnostic scale. The present study aims at extending the validation of the MPQ to people from three different clinical settings. Methods: A multicentre, cross-sectional study on adults diagnosed with migraine (n = 256), systemic sclerosis (n = 219), or mental disorders (n = 138) was conducted. The MPQ was administered; Rasch and Mokken analyses were performed to assess clinimetric validity. Results: The overall fit to the Rasch model indicated a misfit, improved by the exclusion of a single item. MPQ showed to be unidimensional. MPQ total score and individual items scalability were optimal except for the same item. The total MPQ score showed an optimal scalability for the systemic sclerosis sample and an acceptable scalability for the migraine and mental disorders samples. Local dependency was found between two pairs of items. Person separation reliability indices (PSI 0.45) showed that the MPQ could not distinguish between groups with different levels of mental pain. Conclusion: Mental pain has the potential to serve as a truly generic patient-centred outcome measure. Recommendations are made for revisions of the original MPQ, but these will require testing in further validation studies.