Background: The growing populations of elderly people in sub-Saharan Africa are exposed to social changes with potential adverse effects on mental health. Our aim was to estimate the occurrence and effect of major depressive disorder in a large and representative community sample of elderly Africans.
Methods: Face-to-face interviews with a representative sample of people aged 65 years and older (n=2152) were obtained by a multistage stratified sampling of households in the Yoruba-speaking areas of Nigeria (about 22% of the national population). Major depressive disorder was assessed with the WHO composite international diagnostic interview and diagnosed with the Diagnostic and Statistical Manual of Mental Disorders, fourth edition.
Findings: Lifetime and 12-month prevalence estimates of major depressive disorder were 26.2% (95% CI 24.3-28.2) and 7.1% (5.9-8.3) respectively. Female sex (odds ratio [OR] 1.9) and increasing levels of urbanisation of residence (OR 1.4) were associated with this disorder. People with major depressive disorder had impaired quality of life and functioning in home, work, and social roles. Independent ratings of symptom severity confirmed the presence of clinically significant depression in 96.9% of those with diagnosis, and increasing symptom severity was associated with greater disability and poorer quality of life. Only about 37% of lifetime cases had received any treatment, and there was a mean delay of 5 years from onset of depression to receipt of first treatment. Low economic status (0.3) and rural residence (1.0) predicted no treatment.
Interpretation: Major depressive disorder is common in elderly Nigerians and its occurrence is related to urbanisation. This disorder is a seriously disabling illness in this group but only a few sufferers have ever received treatment. Health-care services need to invest in effective treatment programmes for major depressive disorder.