The epidemiology of major depression and ethnicity in the United States
Introduction
In the coming decades, unipolar depression is projected to be the second leading cause of disability worldwide and the leading cause of disability in high-income nations, including the United States (Mathers and Loncar, 2006). Within the US, depression is a leading cause of disability among major ethnic and racial groups and a common problem in medical comorbidity (McKenna et al., 2005). Several technical problems have impeded the ability to identify disparities in depression prevalence and treatment access and quality. The aggregation of ethnic subgroups (i.e., all Latinos or Asians as opposed to specific ethnic subgroups) in national studies creates uncertainty. As a result this practice is discouraged by the Surgeon General and the National Institutes of Health because important differences in major depression are overlooked by “masking” intra-ethnic differences (IOM, 2003; Jimenez et al., 2010; Alegría et al., 2008b). Furthermore, discrete determinants of seeking and obtaining treatment for depression and related disability and treatment use, such as variable access to insurance, are similarly masked when ethnic groups are lumped together (González et al., 2010).
Several recent studies have reported that differences in depression exist within ethnic groups; however, those studies did not present comprehensive comparisons across groups (e.g., Whites and Filipinos) (Williams et al., 2007; Alegria et al., 2007a, Alegria et al., 2007b, 2008a). Our current understanding of the epidemiology of major depression is further complicated because in the United States, mood disorders are combined (e.g., major depression and dysthymia) which makes it difficult if not impossible to specify the prevalence of this leading cause of disability (Jimenez et al., 2010; Williams et al., 2007; Alegria et al., 2008b; Kessler et al., 2003). Extant prevalence estimates are often presented in broad demographic and sociodemographic categories and some are outdated, particularly for older adults. Prevalence estimates for major depression among older adults rely on data from the Epidemiologic Catchment Area (ECA), which are over 30 years old and preceded major changes in current diagnostic criteria and demographic composition, especially shifts in the age structure and ethnic composition of the U.S. population in the new millennium (Weissman et al., 1988; Blazer et al., 1987). Later work with original ECA data have yielded interesting ethnic/racial comparisons of depressive symptoms and patterns of psychopathology among older adults; however, these aggregated data do not permit within ethnic/racial groups (e.g., African Americans and Caribbean Blacks) comparison (Rabins et al., 1996; Gallo et al., 1994, 1998). One purpose of this study was to provide a concise and precise report on the epidemiology of major depression among major ethnic and nativity groups across adulthood in the United States. Secondly, we compared the epidemiology of major depression within major ethnic subgroups. To achieve these objectives, nationally representative data were disaggregated by ethnic and nativity groups to provide prevalence estimates of US adults who met criteria for 12-month and lifetime major depression.
Section snippets
Data collection
The National Institute of Mental Health’s Collaborative Psychiatric Epidemiology Surveys (CPES) data were used in this study. The CPES combines three nationally representative studies: the National Survey of American Life (NSAL), the National Comorbidity Survey-Replication (NCS-R) and the National Latino and Asian American Study (NLAAS). Data for the CPES were collected between February 2001 and November 2003. Specially trained non-clinician interviewers administered face-to-face
Prevalence
The CPES sample is described in Table 1. Educationally, Vietnamese, Latinos and African Americans were the least likely to complete high school, and the most likely to fall into the lowest annual household income brackets. Both past year (χ2 = 33.7; P < 0.001) and lifetime (χ2 = 4.6; P < 0.001) major depression varied by ethnic groups with the highest prevalence among Puerto Ricans and the lowest among all three Asian groups (Table 2). Overall, the prevalence of past year major depression was
Discussion
The epidemiology of major depression in the United States between ethnic and nativity groups varies in prevalence rates, age of onset, severity, disability, and treatment use. This is the first US national study to provide a comprehensive and detailed view of major depression among important US ethnic groups throughout adulthood, and decomposed into ethnic subgroups. Additionally, this is the first study to provide ethnic comparisons of the epidemiology of major depression, chronicity,
Conclusion
Major depression is a leading cause of disability worldwide and in the United States (Murray and Lopez, 1997; McKenna et al., 2005). We found both excess recurrence and greater severity of major depression among the largest and most socioeconomically disadvantaged US ethnic minorities, namely Mexican and African Americans, concurrent with inequalities in mental healthcare. Secondly, our findings provide support for presenting disaggregated ethnic/racial groups and that ignoring these important
Acknowledgements
The authors would like to express their sincere thanks to Susan L. González, MNP, RN, for assistance with reviewing medications.
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