Current estimates of national, state-level, and county-level prevalence of US adults reporting a lifetime diagnosis of depression

By Pooja Toshniwal PahariaJun 19 2023Reviewed by Danielle Ellis, B.Sc.

In the recent Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report, researchers presented nationwide, statewide, and countywide depression prevalence estimates among United States (US) adults in 2020.

Background

In the United States, depression is one of the causes of morbidity, mortality, and financial expenditures and has also been linked to the development of various chronic diseases, including diabetes and cardiovascular disease. Evaluating the geographical variations in the statewide and countywide depression prevalence can aid in directing local and governmental efforts toward the areas with limited resources or inaccessibility to health services to prevent, manage, and treat depression and improve mental well-being.

About the report

In the present report, researchers evaluated the prevalence of depression among adult US residents at the county, state, and national levels during 2020.

The state-based ongoing, random-digit–dialed mobile phone and landline behavioral risk factor surveillance system (BRFSS) survey data for 2020, including data for US adults among all 50 US states, including the participating US territories and the District of Columbia (DC), were analyzed by the CDC. The participants were asked whether they had been diagnosed by a healthcare professional, such as a doctor or a nurse, with depressive disorders such as depression (major or minor) and dysthymia.

Multilevel regression modeling and post-stratification were performed to estimate county-level prevalence since the BRFSS survey is not intended to yield county-wise data. Depression was used as the dependent binary variable, and the independent statistical variables were age, sex, ethnicity, race, and level of education from the BRFSS 2020 survey data and countywide poverty information from the American Community Survey (ACS) conducted between 2016 and 2020.

The team applied the parameters to the Vintage 2020 countywide data of the US Census Bureau to obtain countywide estimates using Monte Carlo simulations. They validated the modeled countywide prevalence estimates by contrasting the rates obtained with weighted BRFSS estimates for US counties comprising ≥500.0 individuals. The estimated depression prevalence rates were matched to the 2,000 United States Census Bureau data by age, reviewed by the CDC, and conducted following the applicable CDC policies and federal laws.

Results and discussion

In total, 99% (n=392,746) responded to the BFRSS survey question on depression. In 2020, 18% of US adults reported having ever been diagnosed with depression; statewide age-standardized estimates ranged between 13% (Hawaii) and 28% (West Virginia); most of the affected US states were in the southern Mississippi Valley and Appalachian regions. The states where depression was most prevalent included West Virginia, Tennessee, Kentucky, Arkansas, Alabama, Vermont, Washington, Louisiana, Montana, and Missouri.

Model-based age-standardized countywide prevalence estimates among 3,143 counties ranged between 11% and 32%, with considerable countywide and statewide variability. Most US counties with the highest prevalence were located within the southern Mississippi Valley and Appalachian areas, as well as Washington, Missouri, and Oklahoma.

The combined (cellular and landline) median response rates for the 2020 BRFSS (except for US territories) were 48% and ranged between 35% and 67% for US states. Stratified by age, depression was most prevalent in individuals aged 18.0 to 24.0 years (22%) and the lowest among older adults aged 65 years and above (14%).

The age-matched depression prevalence rates were greater for females (24%) than males (13%), higher among adult non-Hispanic Whites (22%) compared to those among non-Hispanic African-Americans or Blacks (16%), Native Hawaiians and other Pacific Islanders of non-Hispanic ethnicity (15%), Hispanics or Latinos (15%), and Asians of non-Hispanic ethnicity (7.0%). Depression was also more prevalent in individuals who had lesser than high school-level educational attainment (21%) compared to those who had high-school level attended high school (19%) or colleges and/or degree universities (15%).

Stratified by geographical regions, depression was most prevalent at the county level and state level in the South Mississippi Valley and Appalachian regions, which may reflect patterns of chronic conditions such as cardiovascular diseases, diabetes, and arthritis. The estimates may also vary by socioeconomic status since Appalachian residents have lower levels of education, lower annual income, and increased poverty, which could negatively impact their health.

Conclusions

Overall, the findings showed that in 2020, nearly one out of five US adults would have been documented as having been diagnosed with depression by healthcare providers, with a higher prevalence among younger, female, and less educated individuals. Prior reports emphasizing the prevalence of depression in the previous two years instead of lifelong depression showed comparable differences among subgroups, including those noted before and after the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic.

The findings could inform decision-making and guide resource allocation to high-priority areas with the greatest health inequities by executing practices advocated by the Substance Abuse and Mental Health Services Administration (SAMHSA) and the Guide to Community Preventive Services Task Force (CPSTF).