Adults aged 40 years and older who reported a history of repetitive head impact through contact sports, abuse, or military service had more symptoms of depression and difficulties in cognitive functioning, compared with those without such a history, according to a study published online in the journal Neurology.
“The findings underscore that repetitive hits to the head, such as those from contact sport participation or physical abuse, might be associated with later-life symptoms of depression,” said researcher Michael Alosco, PhD, an associate professor at Boston University School of Medicine and co-director of the Boston University Alzheimer’s Disease Center Clinical Core, Massachusetts. “It should be made clear that this association is likely to be dependent on the dose or duration of repetitive head impacts and this information was not available for this study.”
The cross-sectional investigation spanned 13,323 adults, with an average age of 62 years, from the internet-based Brain Health Registry. Among them, 5% reported exposure to previous repetitive head impact.
On measures of depressive symptoms, participants with no history of repetitive head impacts or traumatic brain injury had the fewest symptoms. From there, a dose-response pattern emerged: depressive symptoms increased with a history of traumatic brain injury alone; depressive symptoms were higher with a history of both traumatic brain injury and repetitive head impacts; and depressive symptoms were highest with a history of traumatic brain injury that resulted in a loss of consciousness along with repetitive head impact, according to the study.
When repetitive head impacts and traumatic brain injury were examined separately, a history of repetitive head impact had the strongest effect on depressive symptoms, researchers reported.
Computerized cognitive tests of memory, learning, processing speed, and reaction time also showed a cumulative effect among participants exposed to repetitive head impact and traumatic brain injury. Compared with those without any head trauma history, participants with a history of repetitive head impacts or traumatic brain injury performed worse on some of the tests. Those with a history of both repetitive head impacts and traumatic brain injury with a loss of consciousness had poorer performance on almost all the cognitive tests.
“These findings add to the growing knowledge about the long-term neurological consequences of brain trauma,” said researcher Robert Stern, PhD, a professor at Boston University School of Medicine and director of clinical research at the Boston University Chronic Traumatic Encephalopathy Center.
“It should be noted that not all people with a history of repetitive hits to the head will develop later-life problems with cognitive functioning and depression. However, results from this study provide further evidence that exposure to repetitive head impacts, such as through the routine play of tackle football, plays an important role in the development in these later-life cognitive and emotional problems.”