Risk factors for sports-related concussion

Patient-related (intrinsic)	Injury-related
General risk factors
Any prior SRC Younger age (children and teenagers at higher risk) Female sex Participation in collision sport (eg, rugby, American football, ice hockey) or combat sport (eg, MMA, boxing)	High impact density (multiple impacts with little time between)
Risk factors for prolonged recovery*
Prepubescent Prior SRC with protracted recovery Past medical history of migraine, psychiatric disorder^¶, epilepsy	High-risk mechanism (double hit; rotational blow to head) Continued sport participation after initial injury Delayed evaluation and treatment High early symptom burden Vestibular dysfunction soon after injury (eg, on-field dizziness) Disordered sleep or exercise intolerance resulting from injury

SRC: sports-related concussion; MMA: mixed martial arts.

* An SRC with a high symptom burden and/or prolonged recovery is considered severe.

¶ Psychiatric conditions conveying risk include depression, bipolar disorder, anxiety, mood disorders, and post-traumatic stress.

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