AUTHOR=Kose Junko , Kesse-Guyot Emmanuelle , Duquenne Pauline , Hercberg Serge , Galan Pilar , Touvier Mathilde , Andreeva Valentina A. , Fezeu Léopold K. 

TITLE=Development of Multimorbidity Indexes Based on Common Mental Health Conditions

JOURNAL=International Journal of Public Health

VOLUME=Volume 70 - 2025

YEAR=2025

URL=https://www.ssph-journal.org/journals/international-journal-of-public-health/articles/10.3389/ijph.2025.1607952

DOI=10.3389/ijph.2025.1607952

ISSN=1661-8564

ABSTRACT=Objectives: Numerous multimorbidity indexes exist, focused primarily or solely on somatic conditions. We developed mental multimorbidity indexes as epidemiological tools. 
Methods: Participants in the French NutriNet-Santé cohort (73.5% women; mean age= 59.5 ± 13.7 y; index development N= 20,000; index comparison N= 7,259) completed self-report questionnaires (2020-2022) regarding depressive symptoms, anxiety, eating disorders, insomnia, alcohol use disorders, cognitive difficulties, and the WHO Disability Assessment Schedule 2.0 (WHODAS 2.0). Using established cutoffs, participants were split into 2 groups for each condition. Tweedie regression analyses were performed with the 6 mental health conditions as exposures and the WHODAS 2.0 score as the outcome. Performance (C-index) and calibration of the indexes were compared with a simple count. 
Results: A general and a sex-specific mental multimorbidity indexes were developed; both were significantly associated with the disability score. The new indexes had slightly better predictive performance than simple counts of mental disorders. 
Conclusions: We developed mental multimorbidity indexes as epidemiological research tools. Future prospective studies could investigate their predictive potential regarding outcomes such as medication use, health care utilization, and quality of life.