Association between social determinants of health and health-related outcomes among adults with mental disorders in the United States, 2008–2018

Adults with mental disorders face a severe and disproportionately high risk of adverse physical health outcomes. This study aimed to evaluate the underexplored dose-response relationship between the cumulative burden of social determinants of health (SDoH) and these adverse outcomes in this vulnerable population. This study is based on nationally representative data from the National Health Interview Survey (NHIS) from 2008 to 2018. We analyzed adults (aged ≥ 18 years) with self-reported mental disorders. A cumulative SDoH index (range 0–7) was constructed from seven domains to quantify the superposition of social disadvantages. Weighted multivariable logistic regression models evaluated associations between cumulative burden and four outcomes: poor general health, all-cause hospitalization, mental health service utilization, and physical inactivity. Among the 4,788 participants included, 32.6% faced a severe cumulative burden. Food insecurity and public insurance were the SDoH factors independently associated with all the observed adverse health outcomes among patients with mental disorders. A significant graded dose–response relationship was observed between cumulative burden and all outcomes ( P < 0.001). Compared with participants with no adverse SDoH burden, those with ≥ 5 SDoH burden faced substantially elevated risks of poor general health (aOR = 7.20, 95% CI: 4.65–11.18, P < 0.001) and all-cause hospitalization (aOR = 3.51, 95% CI: 1.96–6.29, P < 0.001). High cumulative burden was also significantly associated with increased mental health service utilization (aOR = 2.10, 95% CI: 1.46–3.02, P < 0.001) and physical inactivity (aOR = 2.45, 95% CI: 1.51–3.96, P < 0.001). This study reveals a significant dose-response relationship between cumulative SDoH burden and adverse outcomes in patients with mental disorders, with food insecurity and public insurance being key independent drivers. These findings suggest that mental health services for adults with mental disorders should incorporate routine multidimensional social risk screening and cross-sectoral social prescribing strategies.