Scientists have long believed that a single traumatic brain injury (TBI) earlier in life may contribute to problems with memory, thinking and depression later in life. In most previous studies, however, research failed to examine the possible role of having a history of exposure to repetitive head impacts, including those leading to "subconcussive" injuries, in these later-life problems. In the largest study of its kind, an association has been found in living patients exposed to repetitive head impacts and difficulties with cognitive functioning and depression years or decades later
There was a dose-response-like pattern between head trauma and depression symptoms. Specifically, participants without any history of either TBI or repetitive head impacts had the fewest symptoms. While depression symptoms increased when a history of TBI alone was present, depression symptoms were highest for the groups who had a history of both repetitive head impacts and TBI. Indeed, the group that had a history of repetitive head impacts and TBI with loss of consciousness reported the most depressive symptoms.
M.L. Alosco et al.
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