The Anxiety and Depression Association of America states that major depressive disorder is the leading cause of disability in the US. Now, new research has revealed that it is the second leading cause of disability worldwide. This is according to a study published in the journal PLOS Medicine.

Researchers from the US, Canada and Australia, led by Alize Ferrari of the University of Queensland and the Queensland Centre for Mental Health Research, conducted a study that they say reports the most recent and comprehensive estimates on how much death and disability worldwide is a result of depression.

To reach their findings, the research team analyzed information from all published research that studied major depressive disorder and dysthymia – a milder but chronic form of depression.

The researchers added together the “years lived with a disability” (YLDs) and the “years of life lost because of disease-specific premature death” (YLLs) from the studies. This gave them an estimated measure of disease burden, known as “disability-adjusted life years” (DALYs).

Some countries, particularly those that were low-income, presented few published studies to work from, the researchers note. Therefore, the team replaced actual numbers with estimates in order to work out YLDs and DALYs.

They then compared the burden of diseases and injuries worldwide and ranked them in order of their cause.