Relationship between depression and psychosocial functioning after traumatic brain injury11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer benefit upon the author(s) or upon any organization with which the author(s) is/are associated.

We describe the relationship of depression and depressive symptoms to disability days and days lost from work in 2980 participants in the Epidemiologic Catchment Area Study in North Carolina after 1 year of follow-up. Compared with asymptomatic individuals, persons with major depression had a 4.78 times greater risk of disability (95% confidence interval, 1.64 to 13.88), and persons with minor depression with mood disturbance, but not major depression, had a 1.55 times greater risk (95% confidence interval, 1.00 to 2.40). Because of its prevalence, individuals with minor depression were associated with 51% more disability days in the community than persons with major depression. This group was also at increased risk of having a concomitant anxiety disorder or developing major depression within 1 year. We conclude that the threshold for identifying clinically significant depression may need to be reevaluated to include persons with fewer symptoms but measurable morbidity. Only by changing our nosology can the societal impact of depression be adequately addressed.