Two new studies show that National Football League (NFL) players may be at increased risk for depression as they get older because of concussions sustained during their careers.
Preliminary results of the studies, one led by Nyaz Didehbani, PhD, from the Center for BrainHealth at the University of Texas at Dallas, and the other by Kyle Womack, MD, from the University of Texas Southwestern Medical Center, Dallas, were released January 16 and will be presented in March at the American Academy of Neurology 65th Annual Meeting in San Diego, California.
"The hope of our work with former NFL players at the Center for BrainHealth is to increase awareness of the possible role of concussions in the development of depressive symptoms," Dr. Didehbani said.
"We hope that these findings will encourage health practitioners to add a depressive screener to cognitive assessments following concussions or any other type of head injury. Often times, only a few questions related to mood are asked and more specific questions related to negative feelings, for instance feeling self-critical, feeling guilty, and somatic symptoms related to depression, such as loss of energy, changes in sleep and appetite, are overlooked," she said.
The study by Dr. Womack and colleagues used diffusion tensor imaging (DTI) and showed a relationship between white matter damage and depression in former football players.
"DTI measures of white matter integrity correlate highly with depression and may be useful in the future as diagnostic markers," senior author John Hart, MD, commented to Medscape Medical News. "Measures of white matter integrity also provide insights into mechanisms of depression associated with a previous history of concussions."
Immediate and Long-term Disturbance
According to the Centers for Disease Control and Prevention, approximately 1.6 to 3.8 million sports concussions occur each year, Dr. Didehbani told Medscape Medical News. "We know that sports concussions can cause immediate disturbances in mood and thinking, but there have been few studies that have looked at the long-term effects that may emerge later in life, especially those related to depression."
Dr. Didehbani and his group studied 34 retired NFL athletes with a history of concussion and compared them with 29 age- and IQ-matched controls without a history of concussion.
They assessed study participants with several tests, including the Beck Depression Inventory II (BDI-II), the Wechsler Abbreviated Scale of Intelligence, and a full neuropsychological battery, to assess thinking skills, mood, and physical symptoms of depression.
Concussions were retrospectively graded according to 1997 American Academy of Neurology guidelines. On average, the retired NFL players reported having 4 concussions during their playing careers.
The analysis showed a significant correlation between the number of lifetime concussions and the total BDI-II scores (r = 0.50; P = .004).
More specifically, of the 3 depressive symptoms that were assessed (affective, cognitive, and somatic), the researchers found that the cognitive factor was significantly correlated with concussions (r = 0.63; P < .001).
Diffusion Tensor Imaging
The second study used DTI to assess impaired white matter integrity, as defined by reduced fractional anisotropy, in 26 retired NFL players and then looked at a possible association between such impairment and depression.
Five of the retired players had depression; the rest did not.
The analysis showed that by looking at the amount of white matter damage in 1 area of the brain, specifically the forceps minor, the researchers could predict which former players had depression with 100% sensitivity and 95% specificity.
Besides providing a possible future biomarker for depression after concussion, this study may also help researchers to understand similar behavioral symptoms that are seen in other sports-related head injuries, as well as in combat-related blast injuries seen in members of the armed services, Dr. Hart added.
Depression-Brain Trauma Link
Medscape Medical News invited Alexander P. Lin, PhD, clinical spectroscopist at the Center for Clinical Spectroscopy at Brigham and Women's Hospital, Boston, Massachusetts, to comment on these studies.
He called Dr. Didehbani's work "an important first step in characterizing the long-term effects of repetitive brain trauma." However, he pointed out that the small number of participants described in the study is not necessarily representative of the entire population of retired athletes.
"While the correlation of number of concussions with depressive symptoms is a significant finding in this particular group of subjects, correlation alone does not replace a formal risk assessment for depression," he said. "It is unclear from the abstract whether or not they considered other factors that may contribute to depression. Nonetheless, the results of the study do point to the need for understanding the connection between depression and repetitive brain trauma."
With regard to the second study, Dr. Lin said: "Dr. Womack's work takes our understanding of the link between depression and repetitive brain trauma one step further by demonstrating microstructural changes in likely the same cohort or subset of patients.
"While other studies have shown changes in brain fiber tracts, in particular the left superior longitudinal fasciculus, associated with depression, this is the first time that this result has been shown in retired NFL football players," he said.
"It is interesting to note that in this study, only 5 of the 26 players were diagnosed as depressed," he added. "It would have been interesting to see if the number of concussions in the subjects of this particular study differs from the other study and whether it might help explain the structural differences of the fiber tracts. Future studies will hopefully elucidate the biological basis for these changes."
In a statement issued by the Center for BrainHealth, former Dallas Cowboy fullback Daryl Johnston, who participated in the studies and helped recruit other players to take part, said, "Having played 11 years in the NFL and taken countless hits, I've heard about the struggles of the players who came before me and the challenges regarding their quality of life," Johnston writes.
"Through the Center for BrainHealth, former players can find out if there is an issue, and if you catch it early or late, there are things you can do to improve your condition. The brain is regenerative for life, and we can restore faculties that just a few years ago were thought to be lost forever."
The studies were supported by the BrainHealth Institute for Athletes at the Center for BrainHealth. Dr. Didehbani, Dr. Womack, Dr. Hart, and Dr. Lin have disclosed no relevant financial relationships.
American Academy of Neurology 65th Annual Meeting. Abstracts 1136, 2308. Released January 16, 2013.
Medscape Medical News © 2013 WebMD, LLC
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Cite this: Aging Football Players at Higher Risk for Depression - Medscape - Jan 17, 2013.