Post-concussion syndrome (PCS) describes symptoms that persist after a concussion (a mild traumatic brain injury). Loss of consciousness is not required. Symptoms can appear within days and usually improve within three months, but some people experience longer-lasting issues.

• Headache, dizziness, nausea
• Fatigue and sleep disturbance
• Memory and concentration difficulties (“brain fog”)
• Sensitivity to light/noise
• Tinnitus (ringing in the ears)
• Neck pain or cervical strain
• Irritability and mood changes

PCS frequently co-exists with stress-related conditions:

• Post-traumatic stress symptoms (e.g., hypervigilance, intrusive memories)
• Anxiety and/or depression, often linked to sleep disruption, pain, and reduced daily function

If symptoms are persistent or worsening, seek medical assessment. Early management can improve outcomes.

PCS is likely multifactorial. Contributing factors may include:

• Physiological effects of head/neck injury and altered neurochemistry
• Autonomic dysfunction, vestibular/ocular issues, cervical contributions
• Psychological stressors and reduced activity tolerance

There’s no reliable link between how “severe” the initial concussion seemed and who will develop PCS.

A personalised, staged approach tends to work best:

• Medical review to rule out red flags and tailor care
• Symptom-targeted therapy (e.g., vestibular/ocular rehab, graded exercise, sleep hygiene, headache management)
• Return-to-learn/work/sport plans with monitored load
• Mental health support when anxiety, low mood, or PTSD features are present

GLIA is developing a point-of-care test based on microRNA (miRNA) biomarkers to make the “invisible” injury more visible—supporting objective decision-making alongside clinical assessment.
Learn more about our research: microRNA biomarkers.

Our technology is under evaluation and is not yet cleared for clinical diagnosis. We work with clinicians, researchers, defence, and professional sport to validate utility across real-world settings.

• Sport: Guidance on recognition, removal, and staged return: Sport
• Military & Blast Exposure: Persistent symptoms and operational readiness: Military and Blast Overpressure
• Costs & Impact: Why getting PCS right matters to individuals, teams, and systems: Cost of TBI
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Do I need to have blacked out for PCS to occur?
No. Most concussions do not involve loss of consciousness.

My scan was normal—can I still have PCS?
Yes. Conventional imaging often appears normal in mild TBI.

When should I seek help?
If symptoms persist beyond 1–2 weeks, interfere with study/work/sport, or are worsening, speak with a healthcare professional.

• Concussion overview: Concussion
• Subconcussion & cumulative effects: Subconcussion
• Biomarkers & science: Biomarkers 1 • Biomarkers 2 • microRNA
• Clinician tools: Observational Tools • Imaging • Neurocognitive

Disclaimer: This page provides general information only and is not a substitute for professional medical advice, diagnosis, or treatment. If you have concerning symptoms, consult a qualified healthcare professional.

Want to collaborate or learn more?
Contact us.

References 

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2. Silverberg ND, Iverson GL. Is rest after concussion “the best medicine?”: recommendations for activity resumption following concussion in athletes, civilians, and military service members. J Head Trauma Rehabil. 2013;28(4):250–9.
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5. Bryant RA. Post-traumatic stress disorder vs traumatic brain injury. Dialogues Clin Neurosci. 2011;13(3):251–62.
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10. Silverberg ND, Panenka WJ, Iverson GL, Brubacher JR, Brett BL, Li Y, et al. Management of concussion and mild traumatic brain injury: a synthesis of practice guidelines. Arch Phys Med Rehabil. 2020;101(2):382–93.
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12. Di Pietro V, Porto E, Ragusa M, Barbagallo C, Davies D, Forcione M, et al. MicroRNA signatures in traumatic brain injury: diagnostic and therapeutic implications. J Neurosci Res. 2017;95(11):2004–16.
13. Shahim P, Zetterberg H, Tegner Y, Blennow K. Serum microRNAs in concussed professional ice hockey players. J Neurotrauma. 2014;31(17):1608–14