The first worldwide comparison of depression with four other non-fatal chronic diseases shows that feeling seriously blue is the most disabling of all, according to a study released Friday.
Combing through self-reported health data on 245,404 adults from 60 countries collected by the World Health Organization (WHO), researchers found that an average of 3.2 percent of those surveyed had experienced depression over a one-year period.
This was a bit lower than for asthma (3.3 percent), arthritis (4.1 percent), and angina (4.5 percent), and higher than for diabetes (2.0 percent.)
But the results of a quality-of-life index called the "global mean health score" showed that depression was, by a significant margin, the most difficult to bear.
Individuals burdened with diabetes returned an overall satisfaction score of 72.1, and a score of nearly 80 for the three other chronic ailments. Respondents with no chronic diseases scored 90.6 on the 1-to-100 scale.
For those suffering from depression, however, the score was only 72.9.
"Our findings are consistent with earlier studies that have shown a high degree of association between depression and disability," commented lead author Saba Moussavi of the WHO and colleagues.
The study, published in the British journal The Lancet, says that depression accounts for the greatest share of non-fatal disease burden, accounting for almost 12 percent of total years lived with disability worldwide.
The researchers called on doctors around the world to be more alert in the diagnosis and treatment of the condition, noting that it is fairly easy to recognize and treat.
They also note that even if the prevalence of depression is similar to the four other chronic physical diseases, the lifetime risk -- the number of people who cycle in and out of depression -- is five to 10 times greater.