A traumatic brain injury (TBI) is a blow to the head that leads to a skull fracture, internal bleeding, or loss of consciousness for longer than one hour. Concussions are less severe and were analysed separately. Researchers examined Swedish medical records going back 41 years covering 218,300 TBI survivors, 150,513 siblings of TBI survivors and over two million general population controls matched by sex and age. Premature deaths were defined as occurring before age 56.
The results suggested that people who survive six months after TBI remain three times more likely to die prematurely than unrelated controls, and 2.6 times more likely than unaffected siblings. Comparisons with siblings without TBI, controlling for genetic factors and early upbringing, found a strong remaining effect. This supports that TBI may have a true causal effect on premature death. TBI survivors with a history of substance abuse or psychiatric disorder had the highest risk of premature death.
The main causes of premature death in TBI survivors were suicide and fatal injuries from car accidents and falls. The exact mechanisms behind this link are unknown but may involve damage to the parts of the brain responsible for judgement, decision-making and risk taking. Many survivors were also diagnosed with psychiatric disorders after their TBI.
“These patients are more than twice as likely to kill themselves as unaffected siblings”, said study co-author Niklas Långström, professor at Karolinska Institutet. “Our results suggest that TBI survivors should be monitored carefully for signs of depression, substance abuse and other psychiatric disorders, which are all treatable conditions. It may be a good idea to treat some TBI patients as suffering from a chronic problem requiring longer term management just like epilepsy or diabetes.”
Even relatively minor brain injuries, concussions, had a significant impact on mortality. People with concussion were twice as likely to die prematurely as the control population, with suicide and fatal injuries being the main causes of death. This raises issues surrounding concussions in a wide range of sports, researchers point out.
This research was funded by the Wellcome Trust, the Swedish Research Council, and the Swedish Prison and Probation Service.
Seena Fazel, Achim Wolf, Demetris Pillas, Paul Luchtenstein, Niklas Långström
JAMA Psychiatry, online 15 January 2014, doi: 10.1001/jamaphsychiatry.2013.3935
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