If you have been keeping up with professional sports over the past decade you have likely become aware of increasing coverage of and controversy over concussions. The Center for Disease Control and Prevention in the United States estimates up to 3.8 million concussions occur every year during athletic or recreational pursuits.1 In Canada, the Canadian Institute for Health Information listed sports and recreational activities as the third leading cause of traumatic brain injury admissions to hospital between 2003-2004.2
Despite the increasing attention and awareness this topic has earned, from the professional ranks to the minor leagues, the research surrounding concussion — its definition, diagnosis, management and long-term outcomes — continues to evolve.
What is a Concussion?
The terms “mild traumatic brain injury” and “concussion” are often used interchangeably. According to the 4th International Conference on Concussion In Sport, held in Zurich in 2012, a concussion is a subset of mild traumatic brain injury. It reflects an injury occurring at low speeds that causes the brain to impact the rough surface inside the skull. This results in symptoms or changes that cannot necessarily be identified with currently available imaging like X-rays or computed tomography (CT) scans.3
A concussion results from a blow to the head or body. The force is transmitted to the head, typically leading to changes in coordination, memory, vision or other senses, mood and behaviour quickly following the blow. It should also be noted that loss of consciousness is not necessary when considering whether a concussion has occurred.3,4
In order to diagnose a concussion, several factors should be considered, including an individual’s symptoms (what they experience), signs (what others notice), as well as changes in cognition and behaviour.3 Symptoms that are screened include headache, dizziness and neck pain, blurred vision and balance problems, upset stomach, sensitivity to noise or light, as well as impaired thinking, energy and memory. As well, emotion or anxiety features are also considered, which will be addressed below.4
Where possible, it is valuable to have a thorough medical history and examination prior to participating in activities and again following injury, for the sake of comparison. At the time of an injury, if a concussion is suspected, the athlete should be assessed for emergency concerns. Once those issues are addressed, the athlete should continue with a concussion assessment by a licensed healthcare provider, either on the sideline or by urgent referral to a doctor. Over this initial period of evaluation, the athlete should be accompanied by another person, in case their condition worsens.3
A common tool used to evaluate concussions, looking for symptoms, signs and changes in cognition, behaviour, and sleep is the SCAT3 Sport Concussion Assessment Tool – 3rd Edition. SCAT3 is for use by medical professionals. Others may use the Sport Concussion Recognition Tool.3,4
As mentioned above, evidence of a concussion generally can’t be diagnosed using conventional imaging. CT or magnetic resonance imaging (MRI) scans of the brain typically do not offer much either, unless they identify another injury, such as a fracture or bleeding.3
Though onset generally occurs upon impact, some symptoms or changes may take hours to develop. Typically these resolve in a step-wise manner in a short period, often within a week and a half. Less commonly, impairment may persist.3
In the event that loss of consciousness is suspected, or there are concerns with balance, confusion, memory loss or injury to the face, the athlete should not return to play that day. The following would warrant more urgent attention: impairment in verbal, motor, or eye response (known as the Glasgow Coma Scale), worsening neurological signs and symptoms, possible additional injury to the spinal cord, or changes in cognition or attention.4
Current recommendations for managing concussions center around rest: physical and mental, until symptoms resolve, followed by a slow return to activity. Called the “return to play protocol,” the plan gradually increases physical and cognitive load from “no activity” through to “light-aerobic” and “sport-specific exercise,” followed by “non-contact,” “full contact” and “normal game play.” It is expected that each step may take up to a day, however, if any symptoms return, the athlete should return to one of the earlier stages where there were no symptoms. In those who continue to have symptoms beyond the first few days, light exercise might be beneficial. That said, in up to 15 percent of concussions, symptoms may persist beyond 10 days, in which case it is important to consider other possible causes for the ongoing symptoms, as they tend to be non-specific. This means that any one of the symptoms may have several possible underlying causes.3
As mentioned above, some concerns may arise after the initial injury period of 24-48 hours and would warrant emergent attention. These include worsening headache, profound drowsiness, repeated vomiting, seizures, weakness in arms or legs, unsteady walk or odd behaviour.4
With respect to medications, strategies exist to manage the effects of the concussion or to treat the concussion itself. Regardless of the medications used, it is recommended that an athlete should have no symptoms and shouldn’t be on medication before returning to play.3
Mental Health
As mentioned above, mental health concerns have been associated with traumatic brain injury, with increased attention focused on sports-related concussions.3-5

  • Depression – Several studies involving retired professional athletes have demonstrated increased risk of depression in those with a history of concussions. Increased concussion frequency may be associated with experiences of pessimism, guilt and feelings of worthlessness.5-9
  • Anxiety – Though the evidence is less clear, numerous studies suggest a link between the number of knockouts in retired boxers and anxiety, as well as anxious symptoms described by retired hockey players with a history of concussions.9,10
  • Substance Abuse – Another study in retired NFL players found that among those individuals who were misusing narcotic pain medication, chronic pain and undiagnosed concussions were more commonly linked.11
  • Behaviour – Self-reported concussion frequency has been correlated with worse scores on a number of behavioural scales, with several retired professional athletes noting changes in behaviour and emotional control. 9,12
  • Suicide – Increased suicidal thoughts as well as suicide itself — up to three times the rate in the general population — have been noted in those with a history of concussions. 9,13

Research into concussions, as well as the long-term mental health effects, still has a long way to go. That said, increasing media attention and public awareness, as well as increasing efforts to limit the stigma surrounding mental health, offer tremendous opportunity to expand our understanding. In the meantime, if you feel you may be suffering from a concussion, have persisting symptoms of a concussion, or have mental health concerns, speak with your family physician or go to your local urgent care or emergency department.
And keep your stick on the ice!
1. Daneshvar DH, Nowinski CJ, McKee AC, et al. The epidemiology of sport-related concussion. Clin Sports Med. 30, 1–17, vii (2011).
2. Canadian Institute of Health Information. Head injuries in Canada: a decade of change (1994-1995 to 2003-2004) [Internet]. Ottawa: Canadian Insitute of Health Information, 2006. Available from: http://secure.cihi.ca/cihiweb/products/ntr_head_injuries_2006_e.pdf
3. McCrory P, et al.  Consensus Statement on Concussion in Sport – The 4th International Conference on Concussion in Sport held in Zurich, November 2012.  Journal of Science and Medicine in Sport. 16, 178-189, (2013)
4. SCAT3.  British Journal of Sports Medicine.  47, 259-262, (2013)
5. Finkbeiner NF, et al. Knowing What We Don’t Know: Long-Term Psychiatric Outcomes following Adult Concussion in Sports. The Canadian Journal of Psychiatry. 61, 270-276, (2016).
6. Guskiewicz KM, Marshall S, Bailes J, et al. Recurrent concussion and risk of depression in retired professional football players. Medicine and  Science in Sports & Exercise. 39, 903–909, (2007).
7. Kerr ZY, Marshall SW, Harding HP, et al. Nine-year risk of depression diagnosis increases with increasing self-reported concussions in retired professional football players. Am J Sports Med. 40, 2206–2212, (2012).
8. Didehbani N, Cullum C, Mansinghani S, et al. Depressive symptoms and concussions in aging retired NFL players. Arch Clin Neuropsychol. 28, 418–424, (2013).
9. Caron JG, Bloom GA, Johnston KM, et al. Effects of multiple concussions on retired national hockey league players. J Sport Exerc Psychol. 35, 168–179, (2013).
10. Canto P, Shiong Shu L, Cenina A, et al. Neuropsychological and cognitive profile of retired Filipino boxers. in 21st World Congress of Neurology Vienna Austria 333, e305–e306, (2013).
11. Cottler LB, Ben Abdallah A, Cummings SM, et al. Injury, pain, and prescription opioid use among former National Football League (NFL) players. Drug Alcohol Depend. 116, 188–194, (2011).
12. Seichepine D DR, Stamm JM, Daneshvar DH, et al. Profile of self-reported problems with executive functioning in college and professional football players. J Neurotrauma 30, 1299–1304, (2013).
13. Fralic M, et al. Risk of suicide after a concussion. Canadian Medical Association Journal.  February 8, 2016.  Retrieved from: http://www.cmaj.ca/content/early/2016/02/08/cmaj.150790.full.pdf