Concussions Linked to Depression

Symptoms of depression may stem from brain changes caused by concussions themselves

Psychological or pathological?

Mental health issues, such as depression, have been reported as a long-term consequence of traumatic brain injury.1 When an athlete gets depressed after suffering a concussion, the symptoms of depression are often attributed by coaches, other players and even doctors to psychological fallout from the injury: the athlete's loss of his place on the team, lack of teammate support, the often indefinite timeline to recovery, or the invisible nature of the injury, which can raise questions about whether the athlete is malingering.

A 2008 Canadian study of elite athletes playing contact sports, [2] however, suggests that the symptoms of depression some athletes experience in the weeks, months and even years after a concussion may be the result of physical changes in their brains caused by the concussions themselves.

Researchers at the McGill Neurological Institute in Montreal studied 56 elite male athletes using sophisticated MRI scans that allowed real time tracking of brain function as they performed a mental task.

The findings, reported in the January 2008 issue of Archives of General Psychiatry, showed reduced activity in key regions of the brain of concussed athletes that have been linked in earlier studies with major depression. They also found lower gray matter densities in those areas.

Advice for parents

Research into the long-term consequences of mild traumatic brain injury (MTBI) such as concussion, including a study of retired professional football players reported in the June 2007 issue of the journal Medicine & Science in Sports and Exercise,[3] have already pointed to a link between a history of MTBI and an increased risk of developing major depression later in life - a link the National Football League originally sought to downplay in the wake of the 2007 suicide of former NFL star, Andre Waters, who suffered from long-term depression and admitted to suffering more than 15 concussions during his career, but in recent years has acknowledged.

Because of the implications for a successful outcome, parents of concussed athletes with symptoms of depression should be strongly encouraged to seek testing for their child to determine whether the cause of such depression is psychological (i.e. from being sidelined) or pathological (i.e. from neurological changes in the brain).

Study limitations

A note of caution, however: The study's findings do not necessarily apply to all concussions such as:

  • Athletes suffering "simple" concussions. The study focused primarily on "complex" concussions under the concussion classification recommended by the 2nd International Conference on Concussion in Sport (i.e. concussions leading to persistent post-concussion symptoms), a classification abandoned by the 3rd International Conference in its consensus statment of May 2009. Thus, its findings may not be applicable to the 80-90% of concussions which resolve in a short (7-10 day) period. Symptoms of depression experienced during this limited period are likely to be related to external factors such as reaction to trauma, or missing play rather than internal factors such as brain lesion, or altered physiology.
  • Female athletes. Only male athletes were studied. Because studies have consistently found sex differences in depression, the McGill study may not apply to a female population; and
  • Athletes suffering more severe forms of head injury. The study results may not be representative of serious brain trauma in which lesions are usually visible on conventional MRI or CAT scans.

Regardless of its limitations, the McGill study provides powerful evidence that the risk of severe long-term adverse health effects requires concussions to be taken seriously at every level of sport, from youth sports to the NFL.

For the most comprehensive, up-to-date information on concussions for sports parents, click here.

1. McCrory P, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012.Br J Sports Med 2013;47:250-258.

2. Chen JK, Johnston KM, Petrides M, et al. Neural substrates of symptoms of depression following concussion in male athletes with persisting postconcussion symptoms.  Arch Gen Psychiatry 2008;65:81-89.

3. Guskiewicz KM, Marshall SW, Bailes J, et al. Recurrent concussion and risk of depression in retired professional football players. Med Sci Sports Exerc 2007;39:903-909.

Updated March 29, 2013