The ADHD Research Gap: Why Girls and Women Are Still Missing From the Evidence

The Society Journal | Research Insight

Abstract

Research on attention-deficit/hyperactivity disorder (ADHD) in girls and women has expanded substantially. Yet increased publication does not necessarily mean that the evidence base is complete.

A 2026 scoping review examining research published between 1989 and 2024 identified 487 studies explicitly addressing ADHD in girls and women. Publication volume had increased approximately six-fold, but 71.9% of the literature remained observational. More than half of the studies originated in North America and a further third in Europe, while substantial gaps persisted across reproductive life stages, treatment research, later adulthood and geographically under-represented populations.

Other recent studies raise related questions about recognition. A large Welsh healthcare-record study found that females were diagnosed later than males and were more likely to have anxiety or depression recorded before ADHD diagnosis. A 2025 systematic review found item-level differences in symptom presentation between females and males with ADHD. Meanwhile, emerging research into reproductive hormones suggests potentially meaningful interactions with ADHD symptoms, but the evidence remains comparatively small and methodologically heterogeneous.

The central issue is therefore no longer simply whether girls and women can have ADHD. That question has long been settled.

The more important research question is:

Has ADHD science studied girls and women in sufficient depth to understand how the condition presents, changes and should be treated across their lives?

Current evidence suggests the answer is: not yet.

Keywords: ADHD, women, girls, sex differences, gender, diagnosis, hormones, menopause, research bias, neurodevelopment

Editorial approach

This article is a narrative research synthesis rather than a systematic or scoping review.

It draws primarily on recent systematic reviews, a 2026 scoping review, population healthcare data and peer-reviewed observational research examining ADHD in girls and women.

Throughout the article, terminology follows the underlying research as closely as possible. Some studies classify participants according to sex, others refer to women or females, and some include people assigned female at birth. Sex and gender are related but distinct constructs, and evidence about one should not automatically be assumed to establish conclusions about the other.

More research does not necessarily mean enough research

The scientific literature concerning ADHD in girls and women is growing.

That is an important development.

But one of the most useful studies published in 2026 asked a different question: what does the research landscape itself look like?

Ryu, Kim, Zylowska and Seo conducted a scoping review and network analysis following PRISMA-ScR principles. They searched multiple databases for peer-reviewed studies published between 1989 and 2024 that explicitly identified female participants.

Of 1,838 records screened, 487 studies met the inclusion criteria.

The growth was striking. Research output increased approximately six-fold across the period studied.

But the composition of that literature is equally important.

71.9% of studies were observational.

Geographically, approximately:

53.0% originated in North America

33.3% in Europe

and only

9.4% in Asia.

The review identified six broad research clusters, including behavioural and social interaction, sex-related differences and comorbidities, life-cycle and family impacts, developmental outcomes, pregnancy and pharmacotherapy, and cognition and executive functioning.

The literature is therefore unquestionably expanding.

Yet it remains uneven.

The Society's interpretation is that the challenge has shifted.

The field no longer needs simply more articles about women with ADHD.

It needs stronger research designs, broader populations, better longitudinal evidence and greater attention to life stages that historically received comparatively little study.

The diagnosis gap remains visible in population data

One of the strongest indications of a recognition gap comes from routine healthcare data.

Martin and colleagues examined national healthcare records from Wales involving 16,458 people diagnosed with ADHD, born between 1989 and 2013 and observed within healthcare records between 2000 and 2019.

Only 20.3% of those diagnosed were female.

Across the cohort, the male-to-female diagnostic ratio was 3.9:1.

But that ratio was not constant.

Among people diagnosed before age 12 it was approximately 4.8:1.

Among those diagnosed in adulthood, it fell to approximately 1.9:1.

That pattern matters.

It does not by itself prove that every difference in diagnosis reflects bias. Biological, developmental, behavioural and healthcare factors can all influence prevalence and recognition.

But if the male-to-female ratio narrows substantially as people reach adulthood, one plausible interpretation is that at least some females are being recognised later.

The study provides further evidence consistent with that interpretation.

Males received their first recorded ADHD diagnosis at a mean age of 10.9 years, compared with 12.6 years for females.

Females were also more likely than males to have diagnoses of anxiety, depression or another mental-health condition recorded before their ADHD diagnosis.

The authors suggest that this could reflect, among other possibilities, diagnostic overshadowing: ADHD-related difficulties may initially be interpreted through another psychiatric diagnosis.

That conclusion requires nuance.

Anxiety and depression are genuine and important conditions and commonly co-occur with ADHD. The presence of one diagnosis does not mean another diagnosis is necessarily mistaken.

The concern is instead whether ADHD is sometimes missed because another, more readily recognised presentation becomes the principal clinical explanation.

Are the symptoms themselves being recognised differently?

A common explanation for delayed diagnosis in girls is that females supposedly have “quiet ADHD” while males have hyperactive ADHD.

That formulation is too crude.

Recent evidence suggests genuine average differences in symptom endorsement, but also substantial overlap.

Williams and colleagues published the first systematic review specifically examining ADHD symptoms at the individual item level in females rather than relying only on total symptom scores.

Thirteen studies met the inclusion criteria.

In childhood, females with ADHD were more likely than males with ADHD to endorse particular inattentive symptoms, including difficulty sustaining attention and being easily distracted.

Males were more likely to endorse several overt hyperactive and impulsive behaviours, including fidgeting, difficulty remaining seated, running or climbing when inappropriate, difficulty waiting their turn and interrupting.

In adulthood, however, the pattern became less simple.

Women were more likely to endorse some symptoms including distractibility and difficulties organising tasks, while also endorsing behaviours such as excessive talking and blurting out answers. They also reported more mind-wandering and greater adverse impact in the home.

This is important because it argues against replacing one stereotype with another.

The solution is not to say:

Boys are hyperactive; girls are inattentive.

ADHD presentations are heterogeneous within both sexes.

Instead, the evidence suggests that some symptom patterns may differ on average, and that certain manifestations may be more or less visible within the contexts where referrals are generated.

A classroom-disrupting behaviour is inherently easier for another person to notice than internal distractibility.

Recognition is therefore influenced not only by the severity of a difficulty, but also by its visibility.

Diagnostic systems are used within social systems

An ADHD diagnosis does not begin with a brain scan or blood test.

It typically begins because somebody notices a pattern.

A parent.

A teacher.

A general practitioner.

A psychologist.

An employer.

Or increasingly, an adult recognising their own longstanding difficulties.

This creates an important research problem.

Referral is not a biologically neutral process.

If particular behaviours are more likely to concern adults, disrupt classrooms or attract clinical attention, those behaviours may become disproportionately represented in referred populations.

A 2026 critical review of sex bias in ADHD diagnosis synthesised evidence suggesting that referral patterns, symptom interpretation, diagnostic thresholds and diagnostic overshadowing may all contribute to lower clinical recognition of ADHD in females. The authors emphasise that observed sex differences probably reflect a mixture of genuine psychobiological variation and processes within assessment and healthcare systems.

That is a substantially more defensible position than claiming either that all diagnostic differences are biological or that all differences are caused by bias.

Both biology and recognition processes may matter.

What happens when diagnosis arrives late?

Quantitative healthcare records can demonstrate diagnostic patterns.

They cannot fully show what delayed recognition feels like.

Holden and Kobayashi-Wood addressed that question in a 2025 Scientific Reports study involving 28 UK women diagnosed with ADHD after age 15.

Participants ranged in age from 19 to 72, and their ages at diagnosis ranged from 18 to 62.

The researchers used a mixed-methods online survey examining participants' experiences before and after diagnosis.

Participants frequently described criticism, self-blame, low self-esteem and feeling that their difficulties had been dismissed.

All participants reported that delayed diagnosis had affected adolescence. Large majorities also perceived effects on mental wellbeing, their sense of self, employment or career, and relationships.

Many described diagnosis as providing a framework through which earlier experiences could be reinterpreted.

These findings are compelling.

They should also be interpreted within the limits of the study.

Twenty-eight participants constitute a small sample. Most were white, most were employed and a high proportion had experience of higher or further education. Participants were recruited specifically because they had received a later diagnosis.

The study therefore does not establish that every late-diagnosed woman has the same experience.

Its strength lies elsewhere.

It provides detailed evidence about experiences that may not be adequately captured by diagnostic statistics alone.

That distinction between population evidence and lived-experience evidence is important for The Society.

Both can inform understanding.

They answer different questions.

The hormonal question: increasingly discussed, still inadequately studied

Perhaps no area illustrates the female ADHD evidence gap more clearly than reproductive hormones.

Public discussion about ADHD and menstrual cycles, pregnancy, postpartum changes and menopause has accelerated rapidly.

The scientific literature is much smaller.

Osianlis and colleagues conducted a systematic review published in 2025 examining sex hormones and ADHD symptoms in females.

Searches covering literature from 1980 to January 2025 produced only 11 eligible studies.

The overall evidence suggested that hormonal changes may be associated with changes in ADHD symptoms, particularly around puberty and across the menstrual cycle.

But the authors emphasised substantial limitations:

the number of studies was small,

many individual samples were small,

participant populations differed,

and outcome measures varied considerably.

Their conclusion was therefore appropriately cautious: there is suggestive evidence of an association, but considerably more research is required.

This is precisely the type of research area in which scientific uncertainty needs to be communicated clearly.

A biologically plausible hypothesis is not the same as an established clinical mechanism.

A 2026 study provides new evidence, and new questions

An important study published in the Journal of Psychiatric Research in 2026 expanded the evidence base.

Osianlis and colleagues surveyed 600 female participants who reported ADHD diagnoses and ADHD symptoms.

Participants completed measures relating to ADHD, depression, anxiety and stress and were asked about perceived changes across hormonal life stages.

Among premenopausal participants who were not taking hormonal therapy, 88.6% reported perceived changes in ADHD symptoms across the menstrual cycle, most commonly worsening during the luteal phase.

Participants also commonly reported perceived worsening during postpartum and menopausal periods.

However, an important finding prevents simplistic interpretation.

When researchers compared Adult ADHD Self-Report Scale scores cross-sectionally across hormonal life phases, symptom severity was broadly similar.

This apparent tension is scientifically useful.

Participants may perceive meaningful within-person fluctuations even when comparisons between different groups at different life stages do not show corresponding differences.

But the study was cross-sectional and relied substantially on self-report and retrospective perception.

It therefore cannot establish that hormonal change directly caused the reported symptom fluctuations.

The appropriate interpretation is not:

Hormones have now been proven to worsen ADHD.

It is:

A sizeable self-report study has identified a pattern worthy of prospective biological investigation.

Menopause exposes the treatment evidence gap

The absence of research becomes even more striking during midlife.

In April 2026, Wynchank and Kooij reviewed pharmacological management of ADHD across perimenopause, menopause and post-menopause.

Their conclusion is significant:

there are currently no randomised controlled trials specifically evaluating ADHD pharmacotherapy in perimenopausal or menopausal women.

Much current practice therefore has to draw on:

broader adult ADHD treatment research,

clinical experience,

small observational studies,

indirect evidence,

and theoretical understanding of interactions between reproductive hormones and neurotransmitter systems.

The review also notes that no studies have directly established how reproductive-hormone fluctuations alter the pharmacokinetics or pharmacodynamics of psychostimulants, atomoxetine or bupropion.

This does not mean existing ADHD treatments are ineffective for women in midlife.

It means something more specific:

the evidence needed to answer female-specific treatment questions remains remarkably limited.

That is the research gap.

Representation is not only about sex

There is another problem.

Much of the literature discussing ADHD research disparities treats “women” as though women constitute one scientifically homogeneous group.

They do not.

The 2026 scoping review found that 86.3% of the literature originated in North America or Europe.

This raises obvious questions about generalisability.

Cultural expectations influence behaviour.

Healthcare systems influence referral.

Socioeconomic circumstances influence access to assessment.

Ethnicity and race may influence how symptoms are interpreted.

Educational structures differ.

Access to medication differs.

Gender expectations differ across societies.

Research overwhelmingly conducted within a small number of high-income regions cannot automatically be assumed to describe all girls and women globally.

Similarly, evidence remains limited concerning the intersection of ADHD with ethnicity, socioeconomic position, disability, gender identity and other aspects of lived experience.

A mature research agenda therefore needs to move beyond the question:

Are females represented?

towards:

Which females are represented, at which ages, in which countries, and under which circumstances?

The problem with treating “female ADHD” as a new stereotype

There is also a conceptual danger in correcting historical under-recognition.

Science could move from one oversimplification to another.

The older stereotype was:

ADHD looks like a hyperactive boy.

The emerging stereotype risks becoming:

ADHD in women means quiet inattentiveness, masking and hormonal sensitivity.

Neither adequately captures the heterogeneity of ADHD.

Some girls are highly hyperactive.

Some boys are predominantly inattentive.

Some women mask difficulties.

Others do not.

Some individuals perceive substantial menstrual-cycle changes.

Others report little change.

Some receive early diagnoses.

Others reach middle age before their difficulties are recognised.

Research should therefore identify patterns and probabilities, not manufacture a second rigid phenotype.

The 2025 item-level systematic review is especially valuable in this respect because it demonstrates both average differences and variation across life stages.

The objective should be greater diagnostic sensitivity without replacing one gendered stereotype with another.

What the evidence currently supports

WHAT WE KNOW

Research specifically addressing ADHD in girls and women has increased substantially.

A 2026 scoping review identified 487 relevant studies published between 1989 and 2024, with publication volume increasing approximately six-fold.

Females continue to be diagnosed later than males in large routine-healthcare datasets.

In Welsh national healthcare records, the male-to-female diagnostic ratio was much larger in childhood than adulthood, and females received ADHD diagnoses at an older average age.

There are also measurable average differences in the endorsement of individual ADHD symptoms between females and males, although these differences do not support a single universal “female presentation”.

WHAT THE RESEARCH SUGGESTS

Referral processes and diagnostic recognition may contribute to some of the observed difference between males and females.

Co-occurring anxiety and depression may sometimes complicate or delay ADHD recognition.

Hormonal changes may interact with ADHD symptoms in at least some females, particularly across menstrual and reproductive transitions.

Late diagnosis may have substantial psychological and social consequences for some women.

These propositions are supported by emerging evidence, but their mechanisms and magnitude remain incompletely understood.

WHAT WE DO NOT YET KNOW

We do not know how much of the difference in ADHD diagnosis rates between males and females reflects:

true prevalence differences,

differences in symptom presentation,

referral patterns,

social expectations,

diagnostic practices,

or interactions among these factors.

We do not yet understand with precision how reproductive hormones influence ADHD symptoms or treatment response.

We have extremely limited trial evidence specifically addressing ADHD pharmacological treatment during perimenopause and menopause.

And much of the existing research cannot tell us whether findings generalise across ethnic, socioeconomic, cultural and geographical populations.

What should be studied next?

The next stage of research should move beyond simply demonstrating that girls and women have been under-studied.

The field now needs studies designed to resolve the consequences of that history.

Longitudinal research

Researchers need to follow girls and women across developmental stages rather than repeatedly comparing different groups at single time points.

This is particularly important for puberty, pregnancy, postpartum periods and menopause.

Prospective hormone research

Studies should combine prospective symptom measurement with direct biological measurement of reproductive hormones rather than relying primarily on retrospective reports of symptom change.

Treatment trials

Women should not simply be included numerically in treatment trials.

Trials should be sufficiently designed and powered to examine sex- and gender-related effects where scientifically appropriate.

The almost complete absence of controlled ADHD pharmacotherapy trials specifically addressing menopause illustrates how substantial this gap remains.

Greater geographical diversity

Research needs stronger representation from Asia, Africa, Latin America and other currently under-represented regions.

Intersectional research

Sex should not be analysed in isolation from ethnicity, socioeconomic circumstances, disability, gender identity and healthcare access.

Better diagnostic research

Studies should examine not only who meets diagnostic criteria but also who gets referred, who gets overlooked and why.

These are different scientific questions.

The research gap has changed

For decades, one of the central problems surrounding ADHD in girls and women was visibility.

That problem has not disappeared.

But it is no longer the whole story.

The scientific literature has expanded dramatically. Researchers increasingly recognise female ADHD, later diagnosis, reproductive transitions and possible differences in symptom presentation.

The next challenge is more demanding.

It is about the depth and quality of the evidence.

A research field can include women and still fail to answer questions that matter specifically to their lives.

It can identify sex differences without explaining them.

It can document hormonal associations without establishing mechanisms.

It can report late diagnosis without identifying precisely where recognition failed.

And it can increase publication volume while remaining geographically and methodologically narrow.

The central question for ADHD research should therefore no longer be:

“Have we remembered to study women?”

It should be:

“Have we designed the research needed to understand ADHD across the full diversity of female lives?”

In 2026, the evidence suggests we are beginning to ask that question seriously.

We are still some distance from answering it.

The Society Research Position

WHAT WE KNOW

Girls and women with ADHD have historically been less visible in research and clinical pathways, and large datasets continue to show later diagnosis among females.

WHAT THE RESEARCH SUGGESTS

Differences in symptom expression, referral pathways, psychiatric comorbidity, social expectations and reproductive biology may all contribute to the female ADHD experience.

WHAT WE DO NOT YET KNOW

We cannot yet quantify precisely how these influences interact, nor do we have adequate evidence across all life stages, populations and treatment contexts.

WHAT SHOULD BE STUDIED NEXT

The priority should be longitudinal, prospective, geographically diverse and sex- and gender-aware research, particularly around diagnosis, reproductive transitions and treatment response.

References

1. Ryu S, Kim S, Zylowska L, Seo J. Mapping the Landscape of ADHD Research in Girls and Women: A Scoping Review and Network Analysis. Journal of Attention Disorders. Published online 21 July 2026. doi: 10.1177/10870547261468155.

2. Williams T, Horstmann L, Kayani L, et al. An item-level systematic review of the presentation of ADHD in females. Neuroscience & Biobehavioral Reviews. 2025;171:106064. doi: 10.1016/j.neubiorev.2025.106064.

3. Martin J, et al. Sex differences in attention-deficit hyperactivity disorder diagnosis and clinical care: a national study of population healthcare records in Wales. Journal of Child Psychology and Psychiatry. 2024. doi: 10.1111/jcpp.13987.

4. Osianlis E, Thomas EHX, Jenkins LM, Gurvich C. ADHD and Sex Hormones in Females: A Systematic Review. Journal of Attention Disorders. 2025;29(9):706–723. doi: 10.1177/10870547251332319.

5. Osianlis E, Thomas EHX, Li Q, et al. ADHD in females: Survey findings on symptoms across hormonal life stages. Journal of Psychiatric Research. 2026;193:208–215. doi: 10.1016/j.jpsychires.2025.11.035.

6. Wynchank D, Kooij S. Pharmacological Management of ADHD in Women Across Perimenopause, Menopause and Post-Menopause. Drugs & Aging. 2026;43:385–395. doi: 10.1007/s40266-026-01291-z.

7. Holden E, Kobayashi-Wood H. Adverse experiences of women with undiagnosed ADHD and the invaluable role of diagnosis. Scientific Reports. 2025;15:20945. doi: 10.1038/s41598-025-04782-y.

The Society Journal publishes research-led analysis across neurodivergence, science, health, society, education and culture. Research Insights distinguish established evidence from emerging findings and unresolved scientific questions.