Abstract
Background & objectives The global population is ageing, with an increase in older adults in lower middle-income countries (LMICs). Fragmented data from LMICs indicate the need for the estimation of mental health disorders to guide policies, resource allocation, and sustainable mental health strategies. This systematic review and meta-analysis calculated the overall prevalence of depressive, anxiety, sleep and substance use disorders in older adults aged ≥60 yr in LMICs. Methods The protocol was registered in PROSPERO (CRD42024503470). A systematic search across PubMed, Scopus, and Cochrane Central was conducted (Dec 2023-Jan 2024), focusing on cross-sectional studies published in English. Quality assessments were conducted using the AXIS tool. A random-effects model was used to estimate pooled prevalence; heterogeneity was calculated using I2 statistics. Results Out of 4,204 articles, 92 studies were included, with the majority from India (n=29), Iran (n=11) and Nigeria (n=9). Pooled prevalence of depressive disorders was 38.76 per cent [95% confidence interval (CI): 34.25-43.28%; n=76; I2=96.89%], sleep disorders 33.58 per cent (95% CI: 27.03-40.14%; n=20; I2=95.76%), anxiety disorders 27.76 per cent (95% CI: 13.74-41.79%; n=13; I2=96.62%), and substance use disorders 26.36 per cent (95% CI: 14.23-38.49%; n=9; I2=96.86%). Depressive disorders were the highest in Africa, while sleep, anxiety, and substance use disorders were at higher rates in Asia. Interpretation & conclusions The findings emphasise the high burden of mental health disorders among older adults in LMICs, which indicate the need for strategic management. Early diagnosis, treatment, and integration of mental health into primary care, along with capacity building of the health care workers, are urgently needed.