Title: Ethnic diversity and depression within Black America
Description: While the literature on Black-white differences in major depressive disorder (MDD) and depressive symptoms is robust, less robust is the literature on how these outcomes are patterned within the US Black population and why differences exist. Given increasing numbers of first-generation immigrants from the Caribbean, sub-Saharan Africa, Latin America, among other regions of the world, as well as increasing numbers of second- and third-generation immigrants, continued aggregation has the potential to mask intra-racial differences between these ethnic-immigrant groups and Black Americans with more distant ancestral ties to Africa (i.e., African Americans). Among these subgroups, the extremely limited data disaggregating the US Black population suggest the following patterns. First, foreign-born Black immigrants have lower levels of MDD and related symptoms relative to US-born Black Americans, a finding which is consistent with theories of foreign-born health advantage. Second, among the US-born, Caribbean adults have higher levels of MDD and related symptoms relative to all other Black Americans, a finding which is inconsistent with theories related to intergenerational declines in health toward convergence to native-born levels.

Lastly, and contrary to results among adults, first- and second-generation Caribbeans have lower levels of depressive symptoms relative to all other Black youth. This dissertation sought to better understand how depression and its related symptoms are patterned within the US Black population, as well as how mechanisms causing these outcomes may vary across subgroups defined by domains related to immigration. Chapter 1 was a systematic review, which comprehensively synthesized depression and related symptoms within the US Black population across these domains, including a summary of mechanisms proposed toward explaining intra-racial variation. Using longitudinal data, Chapter 2 examined whether, and if so when, growth curve models of depressive symptoms varied by immigrant generation contrasts among a representative sample of Black youth followed into adulthood. And using representative data from the largest study of Black mental health, Chapter 3 examined whether the relationship between racial identity, a presumed protective factor against depression and related symptoms, and MDD varied between US-born Caribbeans and all other US-born Black Americans.

The systematic review of Chapter 1 revealed substantial variation in the prevalence of depression and its related symptoms within the US Black population by nativity, region of birth, age at immigration, and Caribbean ethnic origin. Results additionally confirmed that much of what is known about intra-racial heterogeneity comes from a single data source, the National Study of American Life (NSAL). Using longitudinal data of youth followed into adulthood, Chapter 2 found evidence of diverging depressive symptoms trajectories among Black respondents by immigrant generation (first/second-generation compared with third and higher generations); notably, contrasts among Black respondents varied from those of other racial/ethnic groups (Asian, Hispanic/Latinx, non-Hispanic white). Lastly, results from Chapter 3 suggest aspects of racial identity may not be protective for US-born Caribbeans, pointing to variations in racialization experiences as a distal cause. Additional research using larger sample sizes, more diverse subgroups of Black ethnic immigrants, as well as longitudinal data, is needed to further understand patterns of and additional sources underlying heterogeneity of depression and its related symptoms within the US Black population.