2.5 million undiagnosed migraines: Australia's hidden neurological crisis

The most recent data from the Australian Institute of Health and Welfare places the number of Australians living with a neurological condition at 4.5 million — more than double the 2.2 million figure that has anchored previous estimates. The revision was reported by newsGP this week. Of those 4.5 million, 3.9 million are estimated to be living with migraines. Roughly 2.5 million of them — two-thirds — are thought to be undiagnosed.

That is not a small rounding error in health data. It is a figure that describes the lived experience of a significant proportion of the women sitting in waiting rooms across Australian general practice: people who have been managing their own symptoms, absorbing the days lost, and not putting a name to what has been happening in their heads for years.

If you have been told your headaches are “just tension” or “hormonal,” you are not imagining them. And you are not alone.

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What the data actually shows

The AIHW’s 2025 revision comes from combining the Australian Bureau of Statistics’ 2022 National Health Survey with additional modelling from the Social Research Centre. The previous estimate of 2.2 million was based on older, more limited data collection. The new figure reflects a more complete count — not a sudden outbreak of neurological disease, but a more honest accounting of what was always there.

Migraines dominate the revised total, accounting for nearly 90% of all neurological conditions captured. That figure alone is important: when public health discussions use the phrase “neurological condition,” the image most people reach for is stroke, Parkinson’s, or dementia. The reality is that the largest single contributor to neurological burden in Australia is a condition that disproportionately affects women of working age, that is frequently dismissed in clinical settings, and that has treatments a GP can initiate.

Dr Adele Stewart, Chair of the RACGP Specific Interests Pain Management network, noted that migraines are “often under-recognised and undertreated” in her response to the data. That framing matters: under-recognition is not a patient failing. It is a systemic one — and general practice is where it most directly gets addressed or perpetuated.

The condition follows a striking sex and age pattern. Migraines are most prevalent among women aged 25–55. They cluster across the exact decades in which many women are also managing competing cognitive loads: careers, dependent children, ageing parents, perimenopause. The condition does not occur in isolation from the rest of a person’s life. It compounds it.

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The contested part

The AIHW’s revised methodology is likely to attract some statistical debate. Doubling an estimate by changing the survey instrument raises legitimate questions: was the previous figure always an undercount, or does the new modelling overreach? The full methodological appendix has not yet been independently replicated.

What is less contested is the treatment access gap. The Brain Foundation has consistently documented the lag between migraine onset and first diagnosis — often years — and between diagnosis and access to preventive therapy. RACGP training includes migraine diagnosis, but the clinical encounter that captures a chronic pattern across multiple presentations is harder to reliably achieve under time pressure than recognising an acute event.

There is also a real tension in how aggressively to pursue a diagnosis for someone who has habituated to their headaches. Some patients do not want a label. Some have previously been dismissed and have stopped asking. Respecting a patient’s own framing while not leaving an eminently treatable condition unrecognised is a calibration GPs navigate constantly.

The revision does not resolve that tension. What it does is provide a better warrant for the conversation: the scale of undiagnosed migraine in Australia is now much harder to explain away as niche or exceptional.

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What this means this week

Ask the pattern question. In consultations where a woman describes recurrent headaches — however she frames them — asking about frequency, duration, associated nausea, and functional impact takes less than two minutes and completes the informal ICHD-3 screen. Many migraine patients have never been asked those questions sequentially in a single consultation.

Consider the burden. Two or more migraine days per month affecting daily function is the threshold at which most guidelines suggest considering preventive therapy. If a patient is managing with over-the-counter analgesia alone and losing days of function regularly, that conversation is warranted — and the options now include PBS-listed agents across several drug classes, including for patients who have failed earlier preventive trials.

Modifiable factors are not dismissals. Sleep regularity, hydration, aerobic exercise, and stress management all have evidence behind them for migraine frequency reduction. Raising them is not the same as telling a patient her migraines are caused by stress and therefore her problem to solve. They are additions to a pharmacological plan, not substitutes.

Refer when uncertain. Headaches that are new, worst-ever, or associated with focal neurology, fever, or altered consciousness warrant urgent assessment. A first presentation of suspected migraine in a patient over 50 should prompt consideration of secondary causes.

The doubling of the neurological condition estimate is headline-worthy. The real story is the 2.5 million Australians who have been carrying a diagnosable, treatable condition without a name for it — and without the option of access to treatments they may not know exist.

Verdict: yes — the revised AIHW data is reason to be more proactive about asking the migraine question in general practice, particularly with women aged 25–55.

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Sources cited

1. Migraines drive doubling of neurological conditions estimate — newsGP, 23 September 2026
2. Neurological conditions — AIHW 2025 report
3. Brain Foundation — Migraine