Is ADHD Real? Why More Adults Are Being Diagnosed

Short answer: Yes. ADHD is a well-researched condition: in 2021, an international consensus statement approved by 80 authors from 27 countries set out 208 evidence-based conclusions about it.¹ In Australia it’s estimated to affect 6–10% of children and adolescents and 2–6% of adults.² The number of Australians treated for ADHD has risen sharply, proportionally more so for women, and part of that rise may reflect correcting past under-diagnosis.³ But submissions to the Senate inquiry into ADHD also raised concerns about over-medicalisation and the risk of misdiagnosis, so the overdiagnosis debate is a real one.⁴

Is ADHD real?

Yes. ADHD is recognised in the diagnostic manuals Australian clinicians use: it’s mainly diagnosed using the American Psychiatric Association’s DSM-5, and the World Health Organization’s ICD-11 is also used.⁵ The Australian ADHD Guideline, which sets out how ADHD should be assessed and treated, was approved by the National Health and Medical Research Council.⁶

The World Federation of ADHD’s international consensus statement drew only on large studies (more than 2,000 participants) and meta-analyses, which combine the results of many studies.¹ From them, its authors set out 208 empirically supported statements about the nature, course, outcomes, causes and treatment of ADHD, approved by 80 authors from 27 countries, to challenge misconceptions that stigmatise people with ADHD and delay treatment.¹

Other lines of evidence point the same way:

• It runs in families. ADHD is highly heritable, with heritability estimated at 70–80%.²
• There are measurable brain differences, although they’re small averages across groups rather than something visible on one person’s scan.⁷ See the ADHD brain.
• It affects people’s lives. One meta-analysis found people with ADHD were nearly four times more likely not to complete school, and childhood ADHD has been linked with poorer employment, risky driving and poorer physical health in adulthood.²

How common is ADHD in Australia?

The Senate inquiry into ADHD put prevalence at about six to ten per cent of children and adolescents and two to six per cent of adults,⁵ or around 1 in 20 people overall.⁸ Australia’s national mental health survey didn’t measure ADHD,⁹ so adult estimates draw on international research.² See how common ADHD is in Australia.

Why are more adults being diagnosed?

The increase is large. The rate of Australians dispensed ADHD medication under the PBS rose 11-fold, from 2 per 1,000 people in 2004–05 to 22 per 1,000 (about 2% of the population) in 2023–24.³ The rise has been proportionally larger for women: between 2018–19 and 2023–24 the rate for females rose five-fold while the rate for males more than doubled, and among adults, rates are now higher for women than for men.³ Many people are diagnosed as adults: in the United States, a recent study estimated that 6% of adults have an ADHD diagnosis, and that about half of them received it in adulthood.¹⁰

Prescriptions aren’t the same as diagnoses, but they show the trend. Several things help explain it:

• Recognising people who were missed. The Australian Institute of Health and Welfare says the larger increase in females could be due to corrections of previous under-diagnosis.³ The Senate inquiry heard that gender bias has led to under- and misdiagnosis in girls and women, who often learn to mask their symptoms.⁴
• Recognising ADHD in adults. Outdated attitudes that ADHD only occurs in children have created extra barriers for adults,⁴ and adult ADHD is thought to be substantially underdiagnosed.¹¹
• Symptoms that surface later. Symptoms are present in childhood, but they can be hidden by a supportive and structured environment,⁵ and a diagnosis may not happen until their impact becomes more obvious as demands for independence increase.² Women may become aware of their symptoms as adults and seek an assessment themselves.²
• Changes in the diagnostic criteria. The DSM-5 added examples to help apply the criteria across the lifespan, required symptoms to be present before age 12 rather than age 7, and set a threshold of five symptoms instead of six for adults.¹² The Senate inquiry noted that changes in diagnostic tools over the years have likely led to ADHD being underestimated in the past.⁵

New or changed PBS listings explain some of the trends, but the AIHW says they don’t fully explain the increase in dispensing.³

Is ADHD overdiagnosed?

There are genuine arguments on both sides.

Concerns about overdiagnosis were raised in submissions to the Senate inquiry. The Medical Consumers Association warned of the over-medicalisation of the mental health sector and the need for society to allow for individual differences in attention.⁴ Not all health professionals supported the Australian ADHD Guideline. One submission argued that important evidence had been ignored, including the “relative-age effect”: younger children in a class are more likely to be diagnosed with, and medicated for, ADHD than their older classmates.⁴ The Australian College of Mental Health Nurses warned that growing awareness and demand have increased the risk of inadequate assessment and misdiagnosis.⁴

On the other side, there’s evidence that many people are missed. An expert consensus statement on females with ADHD concluded that many girls with ADHD are likely to remain unidentified and untreated, often masking their difficulties with compensatory behaviours.¹³ The Senate inquiry heard of a backlog of adult women who weren’t diagnosed in childhood.⁴

Both can be true at once. Some people may be diagnosed too readily while others go unrecognised for decades, and the answer to both problems is a careful, thorough assessment.

Does everyone have ADHD?

No, but almost everyone has ADHD-like moments. Losing focus in a dull meeting, misplacing your keys or running late now and then is part of being human. Even among children, the American Psychiatric Association notes, many without ADHD have trouble sitting still, waiting their turn or paying attention; what sets ADHD apart is that the symptoms are noticeably greater than expected for the person’s age or developmental level.¹⁰

A diagnosis needs much more than a few relatable traits. Adults aged 17 and over need at least five symptoms of inattention or hyperactivity-impulsivity,¹⁴¹⁰ and the symptoms must:

• have been present before age 12
• occur in two or more settings, such as at home and at work
• have lasted for at least six months
• significantly affect everyday functioning
• not be better explained by another condition.¹⁵

Other things can cause similar problems. Not getting enough sleep can affect your memory, attention and ability to regulate emotion,¹⁶ and depression can cause problems concentrating.¹⁷ That’s why an assessment looks at other explanations, not just a checklist of symptoms. See ADHD symptoms in adults.

ADHD, social media and self-diagnosis

Videos and posts about ADHD can be a useful prompt to look into things, but they can’t assess you. Some of the traits shared online are things almost everyone experiences at times. What separates ADHD from ordinary forgetfulness or distraction is the pattern: symptoms that began in childhood, show up in more than one part of your life and have a real impact on it.

If something resonates, a validated screening questionnaire such as the World Health Organization’s Adult ADHD Self-Report Scale (ASRS) is a more useful next step.¹⁸ A screening questionnaire can’t diagnose ADHD either, but it can help you decide whether to seek an assessment.

How ADHD is properly diagnosed

ADHD is diagnosed through clinical interviews with a health professional, along with medical and psychological assessments, and for an adult diagnosis it needs to be established that your symptoms began in childhood.⁸ The Australian ADHD Guideline says an assessment should include a full clinical and psychosocial assessment, a developmental, mental health and medical history, reports from people who know you, and a medical assessment to exclude other causes of your symptoms.¹⁹ It also says a diagnosis shouldn’t be made solely from rating scales.¹⁹ Read how to get diagnosed with ADHD in Australia.

Frequently asked questions

Is ADHD real?

Yes. ADHD is a well-researched neurodevelopmental condition. An international consensus statement approved by 80 researchers from 27 countries set out 208 evidence-based conclusions about it, and Australian clinicians diagnose it using the DSM-5.

Is ADHD overdiagnosed?

It’s debated. Some groups worry about over-medicalisation and rushed assessments, while others point to evidence that ADHD in adults, and especially in women, has long been underdiagnosed. Both can be true for different groups of people.

Does everyone have ADHD?

No. Most people lose focus or forget things sometimes. ADHD means persistent symptoms that were present before age 12, occur in more than one area of life and significantly affect everyday functioning.

Why are so many adults being diagnosed with ADHD?

Reasons include recognising people who were missed as children, especially women, more awareness of ADHD in adults, and changes to the diagnostic criteria. Growing demand has also raised concerns about the quality of some assessments.

Can you self-diagnose ADHD?

No. Online content and self-tests can be a useful prompt, but many other things can cause similar difficulties, such as poor sleep or depression. Only a qualified health professional can diagnose ADHD.

Next steps

Read how common ADHD is in Australia and how to get diagnosed with ADHD in Australia, or start with the free ADHD self-assessment.

This article is general information only and is not medical advice. Only a qualified health professional can diagnose ADHD. ADHD GP is a private telehealth clinic staffed by AHPRA-registered Australian GPs.

Book your ADHD assessment

References

1. Faraone SV, Banaschewski T, Coghill D, et al. The World Federation of ADHD International Consensus Statement: 208 Evidence-based conclusions about the disorder. Neuroscience and Biobehavioral Reviews. 2021. PubMed PMID 33549739 — Using only studies of more than 2,000 people and meta-analyses, the World Federation of ADHD set out 208 evidence-based statements about ADHD, approved by 80 authors from 27 countries.
2. Australian ADHD Professionals Association. About ADHD (Australian ADHD Guideline). 2022. adhdguideline.aadpa.com.au — ADHD affects 6–10% of Australian children and 2–6% of adults; heritability 70–80%; symptoms begin before 12 though diagnosis may come later; 60–86% persist into adulthood; inattentive presentation most prevalent; up to 80% of adults have another mental health condition; describes executive-function, brain-maturation and dopamine differences.
3. Australian Institute of Health and Welfare. ADHD medications dispensed over time. 2025. www.aihw.gov.au — PBS-dispensed ADHD medication rose from 2 patients per 1,000 population in 2004–05 to 22 in 2023–24; over 4.6 million prescriptions to just under 600,000 patients in 2023–24, 87% psychostimulants. From 2018–19 to 2023–24 the rate for females rose five-fold (4 to 19 per 1,000) while the rate for males more than doubled (11 to 26); by 2023–24 rates for adults were higher in females than males.
4. Parliament of Australia — Senate Community Affairs References Committee. Assessment and support services for people with ADHD — Chapter 3: barriers to assessment and diagnosis. 2023. www.aph.gov.au — Almost all adult ADHD assessment and diagnosis in Australia is done through the private sector, and cost is a barrier to diagnosis. The committee heard that gender bias has led to under- and misdiagnosis of ADHD in girls and women, who are commonly misdiagnosed with other mental health conditions first and often learn to mask their symptoms.
5. Parliament of Australia — Senate Community Affairs References Committee. Assessment and support services for people with ADHD — Chapter 1. 2023. www.aph.gov.au — ADHD occurs in about 6–10% of Australian children and adolescents and 2–6% of adults; heritability is estimated at 70–80%; Deloitte estimated 814,500 Australians living with ADHD in 2019 at a cost of $20.42 billion.
6. Australian ADHD Professionals Association. Australian Evidence-Based Clinical Practice Guideline for ADHD. 2022. adhdguideline.aadpa.com.au — NHMRC-approved national guideline; recommends stimulant medication as first-line pharmacological treatment for adults with ADHD.
7. Hoogman M, Bralten J, Hibar DP, et al. Subcortical brain volume differences in participants with attention deficit hyperactivity disorder in children and adults: a cross-sectional mega-analysis. Lancet Psychiatry. 2017. PubMed PMID 28219628 — MRI mega-analysis of 1,713 people with ADHD and 1,529 controls: accumbens, amygdala, caudate, hippocampus, putamen and intracranial volumes slightly smaller on average; clearest in children, non-significant in adults.
8. healthdirect (Australian Government). Attention deficit hyperactivity disorder (ADHD). 2025. www.healthdirect.gov.au — ADHD is a neurodevelopmental condition that begins in early childhood; around 1 in 20 people in Australia has ADHD; it is partly genetic; an adult diagnosis requires evidence that symptoms began in childhood; learning difficulties can occur alongside it.
9. Australian Bureau of Statistics. National Study of Mental Health and Wellbeing 2020–2022. 2023. www.abs.gov.au — Assessed three groups of mental disorders — anxiety, affective and substance use disorders — and did not measure ADHD.
10. American Psychiatric Association. What is ADHD?. 2022. www.psychiatry.org — ADHD is one of the most common mental disorders affecting children; symptoms must be present before age 12; an estimated 8.4% of children and 2.5% of adults have ADHD.
11. Ginsberg Y, Quintero J, Anand E, Casillas M, Upadhyaya HP. Underdiagnosis of attention-deficit/hyperactivity disorder in adult patients: a review of the literature. Primary Care Companion for CNS Disorders. 2014. PubMed PMID 25317367 — Review of the evidence that adult ADHD is substantially underdiagnosed.
12. American Psychiatric Association. Highlights of Changes from DSM-IV-TR to DSM-5. 2013. www.psychiatry.org — DSM-5 kept the same 18 ADHD symptoms but replaced subtypes with presentation specifiers, required several symptoms before age 12 (previously 7) and set a five-symptom threshold for adults.
13. Young S, Adamo N, Ásgeirsdóttir BB, et al. Females with ADHD: An expert consensus statement taking a lifespan approach providing guidance for the identification and treatment of attention-deficit/hyperactivity disorder in girls and women. BMC Psychiatry. 2020; 20:404. PubMed PMID 32787804 — Expert consensus: the gap between males and females diagnosed with ADHD is due at least in part to lack of recognition and referral bias in females; many girls with ADHD are likely to remain unidentified and untreated, often mask with compensatory behaviours, and are more likely to first be diagnosed with an internalising or personality disorder, delaying the ADHD diagnosis.
14. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). 2013. www.psychiatry.org — Diagnostic criteria for ADHD, including the five-symptom threshold for adults aged 17 and over.
15. Better Health Channel (Victorian Government). Attention deficit hyperactivity disorder (ADHD). 2026. www.betterhealth.vic.gov.au — ADHD has a strong genetic component and is not caused by parenting style.
16. Better Health Channel (Victorian Government). Sleep deprivation. 2014. www.betterhealth.vic.gov.au — Insufficient sleep can impair memory, attention, emotional regulation and the speed of processing information; even short-term sleep deprivation can impair these functions.
17. healthdirect (Australian Government). Depression. 2025. www.healthdirect.gov.au — Symptoms of depression can include problems concentrating, reduced motivation and being less productive at school or work.
18. Kessler RC, Adler L, Ames M, et al. The World Health Organization Adult ADHD Self-Report Scale (ASRS): a short screening scale for use in the general population. Psychological Medicine. 2005. PubMed PMID 15841682 — Development and validation of the ASRS, including the six-item Part A screener.
19. Australian ADHD Professionals Association. Australian ADHD Guideline — summary of recommendations. 2022. adhdguideline.aadpa.com.au — Medication is the most effective treatment for core symptoms, with non-medication treatments adding support (3.1.1); diagnosing clinicians should be registered and trained in ADHD assessment (2.1.1); the diagnosis must be confirmed before starting medication (5.1.2); CBT should be offered to adults (4.2.11); stimulants are first-line for impairing adult ADHD, with heart rate, blood pressure, weight, sleep, mood and anxiety monitored during titration; co-occurring conditions get best-practice treatment.

Sources were last checked on 5 October 2026. See all sources used on this site on our Sources page.