Male athletes with depression after a major sports-related concussion likely have changes in brain function and gray matter volume, reported researchers in the January Archives of General Psychiatry.

“The results suggest that depressed mood following a concussion may reflect an underlying pathophysiology consistent with a limbic-frontal model of depression,” said Jen-Kai Chen, a neuropsychology student at the Montreal Neurological Institute, McGill University, and coauthors. “Given that depression is associated with considerable functional disability, this finding has important clinical implications for the management of individuals with a cerebral concussion.”

BRAIN FUNCTION IMPAIRED IN DEPRESSED ATHLETES

The research team studied 56 male athletes, 40 of whom had a concussion. Those with concussion were involved in contact sports and had been referred to the McGill Sports Medicine Clinic for consultation following their injury. Based on Beck Depression Inventory II (BDI-II) scores, 16 men were classified as not depressed (BDI-II score, 0 to 9), 16 were mildly depressed (BDI-II score, 10 to 19), and eight were moderately depressed (BDI-II score, 20 to 29). The 16 controls were recruited from McGill University varsity hockey and football teams and were screened to ensure that they had no neurologic disorders or history of concussion.

The participants performed a working memory task that required them to keep track of items presented to them during MRI and blood oxygenation level–dependent (BOLD) fMRI examinations. No performance differences were observed among the groups, reported the researchers, and there were no significant differences in brain structure or function between the control group and the nondepressed athletes with concussion. However, significant changes were found in the athletes with concussion and mild depression, and they were even more evident in the participants with moderate depression.

“The severity of symptoms of depression correlated with neural responses in brain areas that are implicated in major depression,” said the authors. The altered responses included increased activity in the rostral anterior cingulate cortex, the medial orbitofrontal cortex, the posterior cingulate, and the left and right parahippocampal gyri, and decreased activity in both the right and left dorsolateral prefrontal cortices, the left insula, and the left striatum. “Voxel-based morphometry confirmed gray matter loss in these areas,” the investigators added.

Although most participants who had higher ratings on the Postconcussive Symptom Scale also had higher depression scores, a few did not. This subgroup with significant postconcussive symptom complaints but normal BDI-II scores showed “similar negative BOLD signal changes as the control group,” and they differed significantly from participants with concussion and depression, especially in terms of decreased activity in the rostral anterior cingulate cortex and the medial orbitofrontal cortex, noted the researchers.

COMMON REGIONS OF IMPAIRMENT

Mr. Chen and colleagues pointed out that the affected brain areas were previously identified as being involved in the working memory tasks. “Dopaminergic input into the striatum and frontal cortex plays a major regulatory role in neural activity in these areas and there is considerable evidence pointing to the role of the dopaminergic system in depression,” they said. “Thus, our finding may indicate an abnormal dopaminergic function within this cortico-striato-thalamic system in athletes with concussion with symptoms of depression.”

The authors noted that their study focused on complex concussions in young male athletes; therefore, their findings may not be generalizable to female athletes or to patients with “simple” concussions in which symptoms disappear within days and depression during this period is likely related to exogenous factors.

—Janis Kelly

Suggested Reading
Chen JK, Johnston KM, Petrides M, Ptito A. Neural substrates of symptoms of depression following concussion in male athletes with persisting postconcussion symptoms. Arch Gen Psychiatry. 2008;65(1):81-89.

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