Researchers have reported that depression is relatively common after brain injury, but most investigators have focused on moderate to severe TBI or have not differentiated among levels of severity.
10 Furthermore, few researchers have examined the effect of preinjury depression levels on postinjury depression symptoms. Busch and Alpern
11 summarized 12 studies on depression after TBI and showed the prevalence of depression after concussion was at least 35%. Rapoport et al
10 found a 15% prevalence of major depression after mild TBI. After all severities of TBI, the prevalence of major depression was 14% to 29%.
10,
12,
13 Researchers
14–
17 examining emotional responses to sport-related concussion also have reported increased levels of depression in athletes after concussive injury.