By Diana Mahoney. Share your thoughts and suggestions at cpnews@elsevier.com
Mild traumatic brain injury is a “silent epidemic,” according to the Centers for Disease Control and Prevention. But the condition has been generating a lot of noise recently.
Reports of studies showing a link between mild traumatic brain injury, or concussion, and lingering alterations in cognitive and motor function in high-profile populations, such as U.S. soldiers returning from Iraq and Afghanistan, college athletes, and professional football players, have begun to give voice to the potential public health burden imposed by such injuries.
Generally defined as a head injury resulting from contact or acceleration or deceleration forces that induce an alteration in mental status (with or without a loss of consciousness) and a Glasgow Coma Scale score of 13–15, mild traumatic brain injury (mTBI) accounts for as many as 90% of all cases of head injury, World Health Organization estimates show.
The acute, outward signs and symptoms of this type of injury appear to be short lived, and patients, families, and even clinicians historically have minimized the potential relationship between the injury and subsequent symptoms of cognitive or other impairment. There is considerable literature reporting the strong association between TBI and psychiatric disorders. Major depression is the most prevalent psychiatric disorder after TBI, with estimated rates ranging from 14% to 77%, according to Theresa A. Ashman, Ph.D., of the Mount Sinai School of Medicine, New York.
In one often-cited study, Dr. Jesse R. Fann of the University of Washington, Seattle, and colleagues investigated the risk of psychiatric illness after TBI among patients in an adult health maintenance organization. Of 939 patients diagnosed with TBI in 1993, the prevalence of any psychiatric illness in the first year after mild TBI was 34%, compared with 18% in the non-TBI control group (Arch. Gen. Psychiatry 2004;61:53–61).
More recently, a study of 2,552 retired professional football players showed a significant association between recurrent concussion and a diagnosis of clinical depression. Compared with retired players without a history of concussion, those who experienced three or more previous concussions were three times more likely to be diagnosed with depression, and those with a history of one or two previous concussions were 1.5 more likely to be diagnosed with depression, reported lead investigator Kevin M. Guskiewicz, Ph.D. (Med. Sci. Sports Exerc. 2007;39:903–9).
“Traditionally, it was thought that depression following a mild head injury was a reaction to the fact that the person had an accident or, for an athlete, he or she could not return to play,” said neuropsychologist Alain Ptito, Ph.D., of the Montreal Neurological Institute and Hospital. Dr. Ptito and his colleagues recently used magnetic resonance imaging to identify neural substrates of depression symptoms related to mTBI in 56 male athletes. “Our study clearly demonstrates that the story is not that simple–that depression [in this population] seems to originate from a cerebral dysfunction.
“The athletes with concussion and depression symptoms showed reduced activation in the dorsolateral prefrontal cortex and striatum and attenuated deactivation in medial frontal and temporal regions,” the authors wrote. “The severity of symptoms of depression correlated with neural responses in brain areas that are implicated in major depression” (Arch. Gen. Psychiatry 2008;65:81–9).
Screening for depression in post-mTBI patients can take as little as 5 minutes and can be achieved by telephone, according to Harvey S. Levin, Ph.D., of Baylor College of Medicine in Houston. Dr. Levin and his colleagues developed a prediction model using a brief screening measure for depression to identify patients with mTBI at high risk for a major depressive episode by 3 months post injury.
The investigators recruited a prospective cohort of 129 consecutive adults with mTBI who were evaluated at a large, metropolitan Level I trauma center. All of the patients underwent CT scans within 24 hours of their injury. They also completed the self-report Center for Epidemiologic Studies Depression scale (CES-D) at 1 week post injury and the current major depressive episode module of the Structured Clinical Interview for the DSM-IV at 3 months post injury.
Logistic regression was used to generate a prediction model of a major depressive episode at 3 months post injury using the CES-D score as an independent variable. Major depressive episode was present in 15 subjects at 3 months post injury (Arch. Gen. Psychiatry 2005;62:523–8).
The findings support the feasibility of the early detection of patients with mTBI who are at high risk for developing major depression, the authors wrote.
The findings also raise the possibility that coordinating outpatient psychiatric services with trauma centers could improve outcomes associated with mTBI by mitigating secondary conditions, they said.