The importance of role disability, that is, inability to work or carry out usual activities, has become increasingly recognized as a major source of indirect costs of illness because of its high economic impact on ill workers, their employers, and society. However, there is limited information on the amount of disability associated with a wide range of specific physical and mental conditions.
New findings published by Kathleen Merikangas from the National Institute of Mental Health (NIMH) and Ronald Kessler from Harvard Medical School and colleagues in the October 2007 issue of the Archives of General Psychiatry show that more than half of U.S. adults have a mental or physical condition that influences their role functioning. In addition, more than 1.3 billion days out of role performance are lost each year in the United States due to mental disorders, and major depression is the mental disorder associated with the largest number of days out of role. The study also found that the number of days out of role owing to mental disorders is roughly half as large as the number of days associated with all chronic physical conditions combined.
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 NIMH. Respondents in the survey were asked how many days they were completely unable to work or carry out their usual activities as a result of problems with their physical or mental health. A wide range of physical and mental disorders was included in the study. The associations between each of the individual physical and mental disorders with days of role disability were examined using innovative methods to sort out the relative effects of co-occurring conditions among people who reported having multiple health problems.