Head Injury and Depression
The University of North Carolina recently published a study involving more than 2500 retired NFL football players. The study confirmed that players who suffered concussions during their career are far more likely to exhibit clinical depression years later. The study directly contradicts the claims by the NFL that concussions don't result in long-term medical consequences, but corroborates the findings of medical studies showing that even "mild" head injuries can have a long-term impact.
The study documented that NFL players who reported no history of concussion reported a depression rate similar to the population at large. The likelihood of depression increased with an increase in the number of concussions suffered. Players who reported suffering three mild head injuries exhibited a twenty percent likelihood of exhibiting clinical depression, compared to a reported rate well under ten percent in the "normal" population.
While the NFL criticized the study for relying upon a survey format, it was professionally peer-reviewed prior to publication and independent experts found that it was likely to be reliable. The authors and the NFL are currently investigating whether a history of concussions increases the likelihood of cognitive impairment and early-onset Alzheimers or dementia.
Previous medical studies have documented the serious long-term consequences which may flow from "mild" closed head injuries in civilian populations. High profile examples from the NFL were cited by both sides of this debate to support or contradict these claims. A neuropathologist claimed that repeated concussions probably contributed to the November 2006 suicide of Philadelphia Eagles linebacker Andre Waters, and New England Patriots linebacker Ted Johnson's neurologist linked his depression and cognitive decline to on-field concussions.
Studies performed outside the NFL have also documented a higher-than-expected fatality rate among head injury survivors, which experts attribute to a combination of impulsiveness, impaired judgment and depression.
It seems apparent that victims of even mild closed head injuries should be examined and watched carefully for head injury sequelae, particularly including clinical depression.