Determinants of depression in Indian tribal adults: Evidence from the Longitudinal Ageing Study in India Wave-I survey

Depression is one of the most common mental disorders, characterized by feelings of guilt/ low self-worth, sadness, tiredness, loss of interest or pleasure, appetite or disturbed sleep and poor concentration1. It is one of the common disorders affecting mental and overall health, especially in later life. Recent studies revealed a high pooled prevalence rate of depression among adults (≥45 yr) in different regions of South-Asian countries (42%)2 and India (34.4%)3. In India, the age-standardized prevalence of depression among the ≥45 yr was found to be 5.7 per cent4. Multiple morbidity conditions, personality traits (dependent/anxious/avoidant), unfavourable life events (separation/divorce/bereavement/ poverty/ social isolation), living situations, alcohol consumption, smoking and a lack of necessary social and financial support are the factors that moderate the determinants of depression in the population aged ≥45 yr567. The burden of depression and its determinants among the elderly have been studied extensively in India3 but limited research has been conducted to assess depression and related determinants among the scheduled tribe (ST) population. Over 104 million ST people were enumerated in the 2011 census in India classified into 705 ST communities and accounting for 8.6 per cent of the total Indian population8. Being one of the most heterogeneous, vulnerable and marginalized segments of society; the ST population mainly resides in relative social isolation inhabiting rural and remote areas and is culturally or ethnographically unique. The ST populations are more vulnerable to mental health issues compared to their non-ST counterparts for multiple reasons.

The rapid social changes altered tribes’ belief systems, lifestyles and community living. The traditional livelihood system of the ST population has been disrupted by modernization leading to the loss of customary rights over traditional sources of livelihood, such as forest land and produce; relegation and development of low self-esteem, thereby causing immense psychological stress9. Migration to urban spaces, acculturation and use of alcohol and other substances make them vulnerable to several mental health issues in general and depression in particular. Further, ST populations are characterized by poorer health indices, a greater burden of morbidity and mortality and limited access to healthcare resources in comparison to similar non-ST populations, even within the same State10.

The mental health of the ST population is one of the most neglected domains in the field of public health as visualized by limited literature and data11. The ST community has poor health infrastructure and scant mental health resources in comparison to other communities residing in similar areas12. Considering the above scenario, the present study was conducted to assess the prevalence and socioeconomic, demographic and health determinants of depressive symptoms among the ST population aged ≥45 yr in India.

Material & Methods

Data source: The present study analyzed data from Wave-I of the Longitudinal Ageing Study in India (LASI) after procuring permission for using the LASI Wave-I data from International Institute of Population Sciences, Mumbai conducted from April 2017 to December 201813. The LASI is the nationwide longitudinal survey to provide a comprehensive insight into the health and socioeconomic status of adults aged 45 yr and above in India. The LASI survey utilized a multistage stratified cluster sample design to cover 72,250 men and their spouses aged ≥45 in India across all States and Union Territories (except Sikkim). Information about depressive symptoms was collected from 70,386 individuals, including 12,215 ST and 58,171 non-ST respondents. The present study focused on only 12,215 ST individuals aged ≥45 yr (7219 aged 45-59 yr and 4996 aged ≥60 yr). Detailed information about the sampling process; and inclusion and exclusion criteria have been provided in the LASI Wave I report13.

Results

Prevalence of symptoms of depression among the scheduled tribe (ST) population aged ≥45 yr in India: According to the CES-D scale, about one-fourth (25.2%; 95% confidence interval: 24.4-26%) ST population aged ≥45 yr experienced depressive symptoms. The prevalence of depressive symptoms among the ST population increased from 21 per cent in the age group 45-49 yr to 29 per cent among ≥70 yr (Chi-square for linear trend=23.55, P<0.001) (Figure). A significantly higher proportion of females compared to their male counterparts reported depressive symptoms. A significantly lower proportion of currently married individuals reported having depressive symptoms compared to other (widowed or divorced or never married) individuals. Nearly three in every ten illiterate ST individuals aged ≥45 yr experienced depressive symptoms during the reference period compared to about one in every ten literate individuals with 10 yr or higher education. A significant difference was observed in the reporting of depressive symptoms by educational status among ST individuals aged ≥45 yr.

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Figure

Percentage of depressive symptoms (CES-D scale) by age group among the tribal population aged ≥45 yr in India, 2017-2018. Note: Based on authors calculation of LASI wave-I raw data.

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More than two-fifths of the ≥45 yr individuals living alone experienced depressive symptoms. In contrast, around one-fifth of ≥45 yr individuals living with their spouse and children experienced depressive symptoms. Nearly 31 per cent of ST individuals aged 45 and above having multiple morbidities reported depressive symptoms compared to 23.4 per cent of ST individuals without any morbidities. Nearly three in every 10 ST individuals in the richest quintile experienced depressive symptoms, ST individuals currently not working, residing in urban areas and physically inactive were also at a higher risk of experiencing depressive symptoms.

Determinants of symptoms associated with depression among the scheduled tribe (ST) population aged ≥45 yr in India: ST individuals with 10 yr or higher education were around 50 per cent less likely to experience depressive symptoms compared to the reference category. ST individuals aged ≥45 yr living with children and others were 36 per cent less likely to experience depressive symptoms compared to individuals living alone. The ST individuals with multiple comorbidities were nearly 40 per cent more likely to experience symptoms of depression as compared to disease-free ST individuals. ST populations residing in different regions were about 2-4 times more likely to report experiencing depressive symptoms compared to the ST population residing in the northeastern region. A detailed description of socioeconomic and demographic determinants of depressive symptoms is provided in Table I. Similar kind of results was also observed based on the multiple linear regression method (Table II).

Discussion

The present study found that one in every fourth ST individuals aged ≥45 yr experienced depressive symptoms which is also similar to the national average13. It was further found that the studied population with ‘10 yr age or higher education’ was less likely to experience depressive symptoms. Education helps to build psychological and economic resources and make individuals more aware of health issues that stave off potential health issues linked with depression in later life16. Previous studies have also reported that illiteracy contributes to depression among older adults1718. Living with children and others significantly reduced the likelihood of experiencing depressive symptoms among the ST population. Similar to earlier studies1819 the married adults in the present study exhibited a lower proportion of depressive symptom as compared to those who were not currently married /unmarried or separated or widowed. Studies have indicated widowhood and solo living (unpartnered) as determinants of poor mental health among the older adult population in general20. This may be owed to the increased stress because of spousal loss; lack of emotional and financial support21. ST people have their unique identity and cultural patterns but owing to rapid urbanization, displacement, acculturation and loss of traditional livelihood, the ST people have faced socioeconomic and mental health issues922232425262728.

Nearly one in every four occasional alcohol drinkers experienced depressive symptoms. Data from India corroborates the high rate of alcohol use among the tribal population29, which is associated with a wide range of social issues such as family dissolution, income loss, and income being diverted from meeting family needs and health problems such as high rates of morbidity and early death30. Emotional problems, distress, societal acceptance of alcohol consumption and peer pressure were cited as the major aetiology for the higher prevalence of substance dependence in ST communities31. ST individuals having multiple morbidities such as hypertension and diabetes were more vulnerable to depression. Depression shares a bidirectional relationship with chronic comorbidities such that the former is a potent risk factor for developing chronic diseases and the latter can also contribute to depression32. Compared to physically inactive individuals, a lower proportion of physically active individuals experienced depressive symptoms. Physically active adult ST, individuals could be either engaged in moderate or vigorous physical activity regime or combination of both13. These physical activities could impact their functional ability, cognitive performance, social connectivity, physical health and overall well-being, thereby reducing the risk of mental health disorders. ST population residing in northeastern regions were least to report depressive symptoms compared to the ST population residing in other regions. These regional differences could be attributed to an array of contextual factors including but not limited to education, dietary habits, co-existing behavioural and chronic health conditions, social setup, profession and physical activity. However, in contrast, to the present study, Singh et al33 found that the general population aged ≥45 yr residing in the southern region were less likely of experiencing depressive symptoms.

The present study is subject to certain limitations. First, the LASI wave-1 data allowed us to examine only the link between determinants and self-reported depressive symptoms. The self-reported information is subject to bias and errors. The multicollinearity among socioeconomic variables is an issue and may be responsible for changes in the direction of the results of some variables. Second, the tools used for screening and diagnosing depressive symptoms cannot replace a comprehensive interview for clinically confirming and diagnosing depression. However, the CES-D tool is useful for public health programmes. Despite the above mentioned limitations, the present study has strengths as well. Owing to scant information on depression among the adult ST population in India, the LASI data offered an opportunity to conduct a pan-India study to assess the magnitude and determinants of depressive symptoms among the ≥45 yr old ST population. This is the latest dataset (released in 2021) in India that allowed us to bring forth the current picture of depressive symptoms among the adult ST population taking into account the representative sample from each State in India.

The present study revealed that the likelihood of experiencing depressive symptoms among adult ST population aged ≥45 yr was negatively associated with 10 or more years of education and living with children and others and positively associated with a region and experiencing multiple morbidity conditions. It is paramount to raise awareness about depressive symptoms and strengthen the availability of mental health services among the ST community through intensive campaigns and engagement of ST individuals along with other key stakeholders to reduce the burden of depression among the ST population. However, more micro level studies are required to monitor the severity of mental health issues and evaluate socioeconomically, and health behaviour variables linked to depression among various ST communities living in different geographic regions, and at various sociodemographic and economic transitional stages. This study provides crucial information for future reference, thereby aiding in the development and planning of depression prevention, control and treatment strategies amongst the ST populations in India.