A general population survey conducted by HCP Professor Ronald C. Kessler, PhD, and colleagues, found that in US adults, mental disorders result in more than 1.3 billion days each year "out of role"—an inability to work or carry out usual activities. This number equals roughly half as many days out of role as those associated with all chronic physical conditions combined. Condition-specific estimates show that major depression, in particular, is among the most impairing of all conditions in terms of total lost days of role performance. These results are based on the National Comorbidity Survey-Replication (NCS-R), a nationwide survey of 9,282 Americans ages 18 and older funded by the National Institute of Mental Health.

This study was published in the October 2007 issue of Archives of General Psychiatry. Read more about the study. Read the abstract on the Archives of General Psychiatry website. Visit the National Comorbidity Survey website.