Access to healthcare and depression severity in vulnerable groups the US: NHANES 2013–2018

Access to healthcare is essential for managing chronic diseases, yet it often poses a barrier, contributing to a significant burden of conditions like depression. This study aimed to investigate the association between healthcare access and depression severity in contemporary free-living adults in the US, with a focus on identifying vulnerable populations. Data from the National Health and Nutrition Examination Survey cycles 2013–2018 were utilized, involving 13,689 participants aged 20 years or older. Multivariable multinomial logistic regression models were conducted, adjusting for various confounding variables. Approximately 17 % of US adults lacked access to healthcare, while 24 % experienced varying levels of depression severity, with 8 % having moderate-to-severe depression. More males faced challenges accessing healthcare, while more females reported diverse levels of depression. Both healthcare access and depression severity were associated with low educational attainment, low familial income, lacking spousal support, lacking health insurance coverage, and worse self-reported overall health. We found a higher vulnerability to moderate-to-severe depression among females (OR (95 % CI): 1.20 (0.91, 1.59)), individuals identifying as the Other ethnic group (1.69 (1.02, 2.79)), and those living without a spouse (1.57 (1.10, 2.26)). Our cross-sectional study cannot establish causality, and potential biases related to self-reported data exist. Access to healthcare emerged as a crucial predictor of moderate-to-severe depression among females, individuals of the Other ethnic group, and those without a spouse. Longitudinal research is needed to confirm and enhance our understanding of factors that shape the relationship between healthcare access and depression in free-living US adults.