Background: Immigrants to Canada tend to have a lower incidence of diagnosed depression than nonimmigrants. One theory suggests that this “healthy immigrant effect (HIE)” is due to positive selection. Another school of thought argues that the medical underuse of immigrants, arising from care access barriers, may be the underlying reason. This unclear “immigrant paradox” is further confounded by the intersecting race–migration nexus. Against this backdrop, this study aims to investigate: compared to the dominant Canadian-born (CB) Whites, whether racialized immigrants would be more likely to screen positive for depressive symptoms; be less likely to receive a mental disorder diagnosis by a health professional; and be more likely to have undiagnosed depression as well as unrecognized depression.
Methods: This population-based study analyzed data of participants (n = 28,951, age ≥45) from the Canadian Community Health Survey (2015–2018). Multivariable logistic regression was employed to examine associations between race–migration nexus and mental health outcomes, including depressive symptoms (Patient Health Questionnaire [PHQ-9] score ≥10). A stringent criterion was employed to interpret p values due to multiple testing for covariates (p < .01). Multicollinearity issue was checked to make sure the variance inflation factor less than 3. For sensitivity analyses, the multivariable-adjusted logistic regression were then repeated via stratifying by the presence/ absence of mood/anxiety disorder diagnosis (M/A-Dx) to predict PHQ-9 depression and unrecognized depression, respectively
Results: Compared to CB Whites, immigrants, regardless of race, were less likely to receive a M/A-Dx by health providers in their lifetime. Racialized immigrants were mentally disadvantaged with increased odds of undiagnosed depression (Adjusted odds ratio [AOR] = 1.76, 99% Confidence interval [CI]:1.30–2.37), whereas White immigrants were mentally healthier with decreased odds of PHQ depression (AOR=0.75, 99%CI: 0.58, 0.96) and poor self-rated mental health (AOR=0.56, 99% CI=0.33, 0.95). For sensitivity tests, among the subpopulation without a previous M/A-Dx (N = 25,203), racialized immigrants stood out to be the only mentally disadvantaged group who were more likely to screen positive for PHQ-9 depression (AOR = 1.45, 99% CI: 1.15–1.82) and to have unrecognized depression (AOR = 1.47, 99% CI: 1.08–2.00) than CB Whites. Canadian-born non-Whites and FB Whites did not differ from CB Whites for PHQ depression and unrecognized depression. Among the subpopulation with a previous M/A-Dx (N = 3,748), there were no significant racial–migration disparities in these two outcome measures (p > .05). Other risk factors for undiagnosed depression include the lack of regular care providers, emergency room as the usual source of care, and being home renters.
Conclusions: Despite Canadian universal health coverage, the burden of undiagnosed depression disproportionately affects racialized (but not White) immigrants in mid to late life. Contingent on race–migration nexus, the HIE in mental health may be mainly driven by the healthier profile of White immigrants and partly attributable to the under-detection (by health professionals) and under-recognition of mental health conditions among racialized immigrants. A paradigm shift is needed to estimate late-life depression for medically underserved populations.
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