What is CTE and how does it differ from other dementias?

Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disease caused by repeated head trauma — not by a single concussive event. Pathologically, it involves abnormal accumulation of tau protein in a distinctive distribution across the brain. It differs from Alzheimer's disease in its tau distribution pattern and in its aetiological link to physical trauma rather than amyloid. CTE can only be diagnosed post-mortem by neuropathological examination. In life, the clinical features — personality change, impulsivity, memory impairment, mood disorders — resemble those of depression, substance use disorders, and other dementias, making antemortem clinical diagnosis speculative.

What should a GP say to a parent asking about children playing contact sports?

An honest conversation: the Australian Sports Brain Bank data shows CTE is present in Australian rugby league players across a range of ages and skill levels, and the sole established cause is repeated head impacts. Researchers in this field have recommended banning contact in all collision sports for children under 14, though this is not yet policy in Australian codes. The most actionable step is to minimise cumulative head impacts — particularly in training, where volume can be controlled. Encourage reporting of any concussive symptoms to the coaching staff and GP, and consider the family's risk tolerance in context of their child's sport participation level.

60% of donated NRL player brains had CTE: what GPs need to know

What just happened

New data from the Australian Sports Brain Bank, presented at the International Sports Concussion Conference this week, found chronic traumatic encephalopathy — CTE — in 31 of 51 donated rugby league player brains. That is 60.8%, spanning players at amateur through professional levels.

Among those diagnosed: Keith Titmuss, a professional player, found to have stage 2 CTE at age 20. Paul Green — a former NRL premiership-winning coach who played at elite level — diagnosed with CTE at 49.

CTE is a progressive neurodegenerative disease. Its sole established cause, researchers state, is repeated hits to the head and body. It can only be confirmed post-mortem, through neuropathological examination of brain tissue. During life, its presentation — memory impairment, impulsivity, anger, anxiety, and cognitive decline — overlaps substantially with depression, substance use disorders, and early dementia.

This is the most significant body of Australian data on the condition to date, and it was presented this week by molecular biologist and data scientist Jennifer Cropley, alongside paper author Professor Alan Pearce from Swinburne University, under the stewardship of Australian Sports Brain Bank director Michael Buckland.

Both-and

What the 60.8% figure tells us — and what it doesn’t

Brain bank studies have an inherent selection bias that requires acknowledging before the prevalence figure does its work in a consulting room. Brains are donated by families who have watched a loved one change — often significantly. That is not a random sample of all former rugby league players. It is a sample skewed toward those who exhibited enough symptoms to prompt families to donate in the first place.

The same limitation has been documented in American NFL brain bank research. Early studies citing CTE rates of over 99% were criticised precisely because of this bias. Later analyses adjusting for self-selection found lower rates in the broader player population, though still substantially elevated above background.

None of this makes 60.8% unremarkable. It means that the brains of people whose families were worried enough to donate showed very high rates of a devastating disease — which tells us CTE is real, it is present in Australian rugby league, and families are encountering it in significant enough numbers to organise donation. What it cannot tell us is that 60% of every person who has ever played rugby league at any level will develop CTE. The signal is real. The extrapolation requires care.

The clinical problem this data creates for general practitioners

Former contact-sport athletes present to general practice with depression, anxiety, irritability, sleep disturbance, and memory complaints. Most of the time, these presentations have explanations that are entirely separate from CTE: the transition out of elite sport is a recognised vulnerability period, and musculoskeletal pain, identity disruption, and alcohol use are common contributors.

For some former athletes, however, the trajectory is different. The irritability escalates beyond what context seems to explain. The memory complaints do not improve with depression treatment in the expected way. The impulse control problems become structural rather than reactive.

There is currently no antemortem diagnostic test for CTE available in Australia. There is no validated blood biomarker. Research-grade PET imaging using tau-binding ligands exists in academic settings internationally, but it is not available in Australian clinical practice. The diagnosis, for now, can only be confirmed after death.

This leaves GPs navigating a real tension: a patient — or his partner — who asks directly whether he might have CTE, based on symptoms and a playing history that spans his twenties and thirties. The honest answer is that the concern is clinically legitimate, the diagnostic tools are not yet available, and management is symptomatic and supportive. That is not a satisfying answer, but it is the accurate one.

For the family in the waiting room

The widow of Paul Green, Amanda Green, has spoken publicly about wanting people to understand this disease so no one else suffered in silence. That framing matters clinically. The partner or family member who brings a former athlete in — or who comes in alone, trying to understand why the person they live with has changed — is carrying a burden that benefits from being named.

Naming it does not mean diagnosing CTE. It means acknowledging that repeated head trauma has established neurological consequences, that those consequences can manifest as personality and cognitive change, and that the person they are describing is not simply “stressed” or “difficult.”

2 cents

The numbers from this week — 60% of donated brains, a 20-year-old with stage 2 disease — are going to reach your waiting room. Parents will bring them in about children playing rugby. Partners will bring them in about husbands who have changed in ways they cannot explain. The conversation will happen whether or not the GP has read the study.

Be ready to give the honest version: the evidence is real and the Australian data is significant; the risk appears to be dose-related to cumulative head impacts; the diagnostic tools are not yet available; and the most actionable advice for current and future athletes centres on limiting contact volume, particularly in childhood. Researchers presenting this week recommended an outright ban on contact in collision sports for children under 14 — that is not yet formal policy in Australia, but it is the direction the evidence is pointing.

For former athletes already symptomatic: support sleep, mood, and alcohol use. Refer to neurology or neuropsychology when the presentation suggests genuine cognitive decline. Consider documenting a formal cognitive baseline.

Verdict: yes — landmark Australian data. The conversation is already in your waiting room.