Presentation (CTI)

OBJECTIVES: This study aimed to validate the cross-national psychometric properties of the Mental Health Quality of Life questionnaire (MHQoL) and develop a standardised toolbox for its scoring, transformation and presentation.
METHODS: Data from the EMPOWER trial (N = 564, from Finland, Spain, UK) were analysed. Internal consistency was assessed using Cronbach’s alpha, and Spearman’s rank correlations examined associations between MHQoL dimensions and the MHQoL VAS. Validity was assessed through construct and convergent validity. Construct validity was examined using measurement invariance testing and multilevel analyses exploring associations between MHQoL dimensions and MHQoL VAS scores, and between EQ-5D-5L dimensions and MHQoL scores. Convergent validity was evaluated by correlating MHQoL scores with established mental health and quality of life measures, including the EQ-5D-5L, PHQ-9, GAD-7, ISI, PSS-4, PRS, and WHO-5. To support standardised MHQoL assessment, an R package and interactive Shiny application were developed.
RESULTS: The MHQoL demonstrated strong internal consistency (Cronbach’s alpha and Spearman correlations > 0.7) across all countries. It also showed robust construct and convergent validity, reflected in moderate to strong correlations with related mental health and quality of life measures. Multilevel analyses supported the instrument’s internal structure and dimensional relationships. To support practical application, the MHQoL Toolbox was released on CRAN, ensuring accessible, standardised implementation.
CONCLUSIONS: : The MHQoL demonstrated good cross-national validity and reliability as a measure of mental health-related quality of life, making it a promising instrument for economic evaluations and mental health outcomes research. The open-source toolbox facilitates standardised, transparent, and user-friendly implementation across diverse settings.