Postconcussion Syndrome (Mild Traumatic Brain Injury)



  • Postconcussion syndrome (PCS) is a constellation of symptoms involving physical, cognitive, and/or behavioral symptoms persisting after a concussion (synonymous with mild traumatic brain injury [mTBI]) that may continue for weeks to years (1).
  • It is difficult to define when concussive symptoms transition to become postconcussive syndrome. A recent consensus suggests persistent symptoms lasting >10 to 14 days in adults and 4 weeks in children (2).
  • PCS may present with any symptoms of concussion including (1)
    • Cognitive
      • Poor focus
      • Poor organization
      • Diminished academic/intellectual performance
      • Slowed response time
    • Physical
      • Headache
      • Nausea
      • Visual changes
      • Light or noise sensitivity
      • Tinnitus
      • Dizziness and balance problems
      • Fatigue and sleep disturbance
    • Behavioral
      • Depression
      • Irritability/emotional lability
      • Apathy
      • Increased sensitivity to alcohol
  • Diagnosis is based on history and clinical symptoms.


The reported frequency of patients with concussion who develop PCS varies widely between 5% and 80%.

  • Largely due to difficulty differentiating postconcussion symptoms from PCS
  • 80–90% of individuals with concussion recover from postconcussion symptoms within 7 to 10 days, slightly longer in children/adolescents (2). A diagnosis of PCS is made in patients with persistent concussive symptoms.

Predominant sex: Females are slightly more likely to experience prolonged symptoms following a concussive injury.

Etiology and Pathophysiology

  • Controversial; exact mechanism(s) unknown
  • Microscopic axonal injury from shearing forces leads to inflammation causing secondary brain injury.
  • Conflicting data on structural brain damage and correlation of imaging with physical symptoms (1)
  • Because the pathophysiology of PCS is not well understood and because of symptom overlap with other psychiatric conditions, PCS remains difficult to diagnose and to manage.
    • Only some individuals with mTBI develop PCS; it is unclear what causes postconcussion symptoms to persist leading to PCS.
    • Behavioral factors are commonly associated with (and may play a role in) the development of PCS. It can be challenging to differentiate some behavioral disorders from PCS (1). Neuropsychiatry evaluation can be helpful.
    • Patients who reported high symptom burden following mTBI are at increased risk of PCS (3)[B].

Risk Factors

  • Strongest predictor is severity of initial symptoms (2).
  • Initial symptoms including retrograde amnesia, difficulty concentrating, disorientation, insomnia, loss of balance, sensitivity to noise, or visual disturbance (4)
  • Preexisting psychiatric disorders including depression, anxiety, personality disorder, and posttraumatic stress disorder (PTSD)
  • Preexisting expectation of poor outcomes following mTBI (1)
  • Nonsport concussion/mTBI
  • Unclear if previous history of concussion(s) is a risk factor for PCS
  • Low socioeconomic status
  • Loss of consciousness is NOT predictive of PCS.

General Prevention

  • Education of players, coaches, parents, and athletic trainers about concussion, PCS, and appropriate safety rules
  • Head injury precautions are advised. Evidence is lacking that these decrease incidence of mTBI/PCS.
  • Screening and intervention for anxiety and depression

Commonly Associated Conditions

  • PTSD
  • Anxiety
  • Depression
  • Fibromyalgia
  • Personality disorders (namely, compulsive, histrionic, and narcissistic)
  • ADHD

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