Understanding Post-Concussion Syndrome (PCS)

Post-concussion syndrome (PCS) describes a set of symptoms – attention difficulties, learning difficulties, impulsivity, mood and anger problems, and often headaches and fatigue – that can persist for weeks, months, or in some cases years after a minor closed head injury (a concussion or mild traumatic brain injury). Most people recover within days to weeks of a concussion, but a proportion of people go on to experience longer-lasting symptoms, which is what PCS describes.

Symptoms of Post-Concussion Syndrome

PCS symptoms are wide-ranging and vary from person to person. Commonly reported symptoms include:

  • Attention deficits and difficulty concentrating
  • Fatigue and low energy
  • Impulsivity and reduced self-control
  • Irritability, temper outbursts and mood changes
  • Learning and memory problems
  • Difficulty planning and organising
  • Inflexibility and difficulty adapting to change
  • Reduced initiative or motivation
  • Feelings of dissociation or being “foggy”
  • Communication difficulties
  • Socially inappropriate behaviour
  • Self-centredness or reduced awareness of others’ perspectives
  • Physical symptoms – balance problems, dizziness and headaches
  • Personality changes noticed by family or friends

Not everyone experiences all of these symptoms, and severity varies considerably. For a general overview of concussion symptoms, the CDC’s HEADS UP resource is a helpful starting point.

Symptoms Have an Organic Basis

Even when standard structural CT or MRI scans appear normal, research using more sensitive imaging – such as cerebral blood flow studies, Quantitative EEG (QEEG) and detailed neuropsychological testing has demonstrated genuine, measurable changes in brain function after concussion. This means PCS symptoms reflect real, organic changes in how the brain is working, even though they are not always visible on routine structural scans.

Why Do Some People Recover Quickly While Others Develop PCS?

The reasons aren’t completely understood, and researchers are still working to explain why two people with a similar injury can have very different recovery paths. Factors that may play a role include:

  • The severity of the initial injury
  • Nutritional status 
  • A history of previous concussions
  • Age at the time of injury
  • Pre-existing mental health history
  • Genetic predisposition

Emotional stress can also contribute to how long symptoms persist. This is one of the reasons a thorough assessment matters – it helps identify which factors are contributing in your particular case, rather than assuming a “one size fits all” explanation.

What to Do Next

If symptoms are persisting beyond the expected recovery window, the next step is usually a clinical assessment. See our Assessment of Post-Concussion Syndrome page for how BNC approaches Assessment, and our Treatment of Post-Concussion Syndrome page for how symptoms are managed.

Frequently Asked Questions

What is post-concussion syndrome?+
Post-concussion syndrome is a set of symptoms – including headaches, dizziness, fatigue, difficulty concentrating, memory problems, irritability and sleep disturbances – that persist for weeks or months after a concussion or mild traumatic brain injury.
How long does post-concussion syndrome last?+
Most people recover from a concussion within days to weeks. When symptoms persist beyond about three months, this is generally when clinicians consider a diagnosis of post-concussion syndrome. Duration varies considerably between individuals.
Can post-concussion syndrome be seen on a CT or MRI scan?+
Usually not. Standard CT and MRI scans are typically normal in PCS, which is why the condition is sometimes wrongly assumed to be “all in the head.” More sensitive research tools have shown genuine, measurable changes in brain function, even when standard scans look normal.
Why do some people recover from a concussion quickly while others develop PCS?+
This isn’t fully understood, but factors that may play a role include the severity of the original injury, a history of previous concussions, age, pre-existing mental health history, genetic predisposition, and ongoing emotional stress.
When should I see someone about persistent symptoms after a concussion?+
If symptoms haven’t resolved within a few weeks, or are significantly affecting daily life, school, or work, it’s worth arranging a clinical assessment rather than waiting to “see if it goes away.”
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Updated on:  23/08/2026 by: Dr Jacques Duff – PhD; BA Psych; Grad Dip Applied Psychology; FANSA, Clinical Neuroscientist.
Reviewed on: 23/08/2026 by: Bernard Ferriere – Clinical Psychologist; BA; Grad Dip Applied Psychology; Dip Clinical Hypnosis; MAPS