Background There is relative little information about the prevalence and risk factors of co-morbid anxiety and depression in later life. These disorders are often associated with worse response to treatment than either condition alone, and researching its epidemiology in diverse settings is vital to policy makers. We therefore investigated the co-occurrence of anxiety and depressive syndromes among older adults living in developing countries and measured the separate and joint effect of these two disorders on levels of associated disability. Method The 10/66 study carried out cross-cultural surveys of all residents aged 65 or over (n=15 021) in 11 sites in seven countries (China, India, Cuba, Dominican Republic, Venezuela, Mexico and Peru). Anxiety was measured by using the Geriatric Mental State Examination (GMS) and the AGECAT diagnostic system. Depression was assessed according to ICD-10 and EURO-DEP criteria. Disability was measured by using the WHO-Disablement Assessment Scale Version II (WHODAS-II). Negative binomial regression models (ZINBs) were used to investigate the association between common mental disorders and disability. Results Co-morbid anxiety and depression was high (range %: 14.4–26.8) in the Latin American and Indian sites. Gender, socio-economic status, urbanicity and physical co-morbidities were associated with the different co-morbid states. Having both disorders was linked to higher disability scores than having anxiety or depression alone. Conclusions Given the close association of co-morbid anxiety and depression with disability, new policies to improve prevention, recognition and treatment will be needed to adapt to ageing populations and their mental health needs.
