A combined analysis of results from 149 earlier studies finds that treatment rates for major depressive disorder remain low worldwide, particularly for people living in low and lower-middle income countries. Alize Ferrari of the University of Queensland, Australia, Modhurima Moitra of the University of Washington, U.S., and colleagues present these findings in the open-access journal PLOS Medicine.

In recent years, national and global initiatives have made increasing efforts to address the tremendous burden posed by major depressive disorder. However, treatment rates remain low. Analyses that combine results from studies on depression treatment from different regions can help identify opportunities for improvement. However, many such analyses do not adequately account for variations in study methods that make results from different studies difficult to compare.

To provide further clarity, Ferrari and colleagues conducted an updated analysis of 149 studies on treatment for major depressive disorder conducted in 84 countries between 2000 and 2021. Applying a statistical method known as Bayesian meta-regression analysis, they combined the studies to examine treatment rates around the world.

The findings of this meta-analysis suggest that treatment rates remain low worldwide, and it highlights disparities in treatment between countries with different resource levels. In particular, use of mental health services by people with major depressive disorder is estimated to be 33% in high-income countries and just 8% in low and lower-middle income countries.

Rates of treatment considered to be minimally sufficient for treating major depressive disorder are lower, estimated at 23% for high-income countries and 3% in low and lower-middle income countries.

The authors note a lack of high-quality data on depression treatment for low and lower-middle income countries, mostly in Sub-Saharan Africa and South Asia; further research could attempt to address that gap and thereby improve the accuracy of the treatment rates reported in this study. Future research could also examine how to best improve treatment access in different regions.

Overall, the researchers say, their findings could help inform efforts by governments and policymakers to more effectively address depression treatment worldwide.

Ferrari adds, "Treatment coverage for major depressive disorder continues to be low globally, with many individuals failing to receive a level of care consistent with practice guideline recommendations. This highlights the need to reconsider the availability of appropriate care and facilitators of treatment as we respond to the large burden imposed by this disorder."