Associations between self-reported depression and functioning across ICF domains: a Danish population-based study.

The study measured depression and functioning at one time, so it cannot show that depression caused these difficulties or that difficulties caused depression. Depression was based on self-reported questionnaire scores, not a clinical diagnosis, and functioning was also self-reported. The survey was collected during the COVID-19 pandemic, when stress, loneliness, sleep, and daily routines were already affected. Survey items were not designed for ICF functioning, and some cut-offs were not formally validated for this population. Adjusted models included variables that may lie between depression and functioning, so some associations may be overadjusted. People with poor mental health may have been less likely to complete the survey, so the associations could be underestimated. The work and education finding changed direction between models, so it should be read as unstable. The sample was Danish adults aged 25 years and older, so findings may not apply directly elsewhere.

Do not read these associations as evidence that treating depression will improve sleep, daily tasks, work, or community participation. The study was cross-sectional and adjusted models may overadjust, so it cannot show cause or treatment benefit.