Post-concussion syndrome

Post-concussion syndrome is a cluster of physical, cognitive and emotional symptoms that persist for weeks to months after a concussion, beyond the usual recovery period.

Most people recover from a concussion within two to four weeks, but a minority continue to experience headache, dizziness, sensitivity to light and noise, fatigue, sleep disturbance, difficulty concentrating and remembering, irritability, anxiety and low mood. The symptoms overlap with migraine, depression, anxiety and sleep disorders, and they are more common after prior concussions, in people with a history of migraine or mental health conditions, and when early symptoms were severe.

There is no single test. The diagnosis rests on a history of head injury followed by persistent symptoms, a neurologic examination, symptom questionnaires such as the Rivermead scale, and cognitive testing, with imaging used mainly to exclude other injury. Assessment also considers sleep, vision and vestibular function, since each can drive symptoms and is addressed separately. Cannabinoids have been studied in animal models of brain injury and in a small number of early human studies; evidence for post-concussion symptoms is not established.