Indigenous population and major depressive disorder in later life: a study based on the data from Longitudinal Ageing Study in India

Background: Existing evidence suggests that the indigenous older population who live with their families and friends might experience lesser depressive symptoms due to better emotional support and well-being. The present study aimed to investigate the differentials in the prevalence of the major depressive disorder among tribal and non-tribal older populations in India and to explore the contribution of socio-demographic, health-related, and household factors in such disparities. Methods: A cross-sectional study was conducted using data from the Longitudinal Aging Study in India (2017-18). The analytical sample included 30,637 older adults, among whom 5,025 and 25,612 belonged to the Scheduled Tribe (ST) and non-Scheduled Tribe (non-ST) social groups, respectively. Major depressive disorder assessed by the Composite International Diagnostic Interview short-form (CIDI-SF) scale was the outcome variable. Descriptive statistics, bivariate and multivariable regression and, decomposition analyses were conducted. Results: About 4.8% and 8.9% of older adults from the ST and non-ST social groups had major depression. For both tribal and non-tribal groups, older adults who were unmarried, dissatisfied with living arrangements, and those who faced lifetime discrimination were at increased risk of major depression. Findings from differences due to characteristics (E) revealed that if the regional differences were minimized, it would decrease the ST-non-ST gap in major depression by about 19.6%. Similarly, equal self-rated health status and chronic conditions among ST and non-ST groups would decrease the gap in major depression by almost 9.6% and 7.9%, respectively. Additionally, an equal status of Instrumental Activities of Daily Living (IADL) and Activities of Daily Living (ADL) among older adults would decrease the gap in major depression by about 3.8% and 3% respectively. Also, findings from differences due to coefficients (C) revealed that if older adults from the ST group had the same status of ADL as of older adults from the non-ST group, it would decrease the gap in major depression by about 11.8%. Conclusion: The findings revealed a greater prevalence of major depression in older adults belonging to the non-ST group than the ST group. For both tribal and non-tribal groups, older adults who were unmarried, dissatisfied with living arrangements, and those who faced lifetime discrimination were at increased risk of major depression and these factors along with health-related variables contributed to significant ST-non-ST gap in depression, advantageous to tribal population; suggesting further research on the coping mechanisms of mental illnesses among indigenous population in India.