AuDHD in Australian Women: What the 2026 Craddock Study Really Says

AuDHD — the shorthand for co-occurring Autism and ADHD — is the most common neurodevelopmental combination in adults, yet it sits in a diagnostic blind spot. A new 2026 study published in the journal Health is the first to ask women diagnosed with both as adults what that blind spot actually feels like. For Australian women navigating Medicare assessments, RANZCP-guided psychiatric care and the NDIS, the findings explain something many already know: the system was not built for brains like theirs.

Key findings

• AuDHD is not a formal diagnosis. The DSM-5-TR and ICD-11 list Autism and ADHD as separate conditions, even though 40–50 per cent of adults with one also meet criteria for the other.
• The 2026 Craddock study interviewed six women diagnosed with both as adults and identified three ways they experience the overlap.
• Three themes emerged: internal conflict ("two separate parts of my brain"), integration ("two sides of the same coin"), and selective identification ("Autism is a part of me, ADHD is an add-on").
• Australian women face the same structural problem: two assessments, two Medicare pathways, and no combined reporting.
• What to change: integrated assessment pathways, combined diagnostic reports, and a dedicated MBS item for adult AuDHD assessment.

The study at a glance

TitleNavigating residual diagnostic categories: The lived experiences of women diagnosed with autism and ADHD in adulthood
AuthorEmma Craddock
JournalHealth (SAGE), 2026
DOI10.1177/13634593251336163
MethodInterpretative Phenomenological Analysis (IPA) of six semi-structured email interviews
ParticipantsSix women, diagnosed with both Autism and ADHD in adulthood, United Kingdom
Relevance to AustraliaThe UK diagnostic system (NHS, NICE, ICD-11) closely mirrors the Australian system (Medicare, RANZCP guidelines, DSM-5-TR), making the findings directly translatable.

What is AuDHD? A definition for Australian readers

AuDHD is the everyday name for co-occurring Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD). It is not listed as a standalone diagnosis in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) or the International Classification of Diseases (ICD-11), and it does not have its own Medicare Benefits Schedule (MBS) item number in Australia. Despite this, it is extraordinarily common: recent meta-analyses suggest between 40 and 50 per cent of adults with ADHD also meet diagnostic criteria for Autism.

In plain English: if you have one, the odds are very high that you have at least traits of the other. AuDHD describes that overlap.

The problem: AuDHD is a "residual diagnostic category"

Until 2013, the DSM explicitly prohibited diagnosing Autism and ADHD in the same person. That restriction was quietly lifted in DSM-5, but the diagnostic infrastructure around it was never rebuilt. In Australia, this means:

• Assessments are conducted against two separate DSM criteria lists, usually by two different clinicians.
• Medicare rebates are claimed under two different items (MBS 291 or 296 for initial psychiatric assessment; MBS 2715 for a GP-prepared Mental Health Treatment Plan).
• The Royal Australian and New Zealand College of Psychiatrists (RANZCP) has separate practice guidelines for each condition, with no integrated AuDHD pathway as of April 2026.
• The National Disability Insurance Scheme (NDIS) assesses functional impact rather than diagnostic label, but the two conditions are still typically described in separate paragraphs of a supporting report.

Emma Craddock, the author of the new study, calls this a "residual diagnostic category" — a liminal space where the person exists clinically and experientially, but the system treats them as two separate cases stitched together.

What the research found: three ways women describe AuDHD

Using Interpretative Phenomenological Analysis (IPA) — a rigorous qualitative method designed to capture lived experience — Craddock identified three distinct ways participants made sense of their AuDHD diagnosis.

Theme 1: "Two separate parts of my brain"

Several participants described AuDHD as an internal conflict. The Autistic part of their nervous system sought routine, predictability, sensory quiet and consistency. The ADHD part sought novelty, stimulation, variety and change. Daily life became a negotiation between these two drives.

This finding is consistent with neuroimaging work from 2025 showing that co-occurring ADHD and Autism produce distinct patterns of brain connectivity rather than simply additive ones. Neurologically, AuDHD is its own profile, not ADHD plus Autism.

Theme 2: "Two sides of the same coin"

Other participants described the opposite experience: Autism and ADHD as two expressions of a single, coherent cognitive style. Autistic deep focus combined with ADHD hyperfocus became a generative force. Autistic pattern recognition combined with ADHD divergent thinking became creative intelligence.

For this group, the AuDHD diagnosis was experienced as clarifying rather than fragmenting.

Theme 3: "Autism is a part of me, ADHD is an add-on"

The third theme is the most politically loaded. Some participants integrated Autism into their identity while framing ADHD as a medical condition they would willingly treat — or eliminate — if they could. This reflects the wider tension between neurodiversity-affirming approaches (common in Australian Autistic-led advocacy) and medical-model approaches (still dominant in Australian psychiatry).

Craddock argues this framing is a rational response to a cultural environment that codes Autistic traits as personality and ADHD traits as dysfunction — even when both are produced by the same nervous system.

What this means for Australian women seeking diagnosis

The Craddock study was conducted in the United Kingdom, but the diagnostic architecture it describes is almost identical to Australia's. Here is how the findings translate:

• Medicare. A full adult assessment in Australia involves a GP referral (MBS 44, ~$85 rebate), optional Mental Health Treatment Plan (MBS 2715, ~$100 rebate), and a psychiatric assessment (MBS 291 or 296, ~$440–$520 rebate). None of these items are AuDHD-specific.
• RANZCP guidelines. The College publishes separate clinical practice guidance on ADHD (updated 2025) and Autism (last updated 2018), with no combined pathway.
• NDIS. Access is functional-impact based under the 2026 reforms. Autism alone no longer guarantees access; AuDHD is assessed through the same functional lens.
• Private cost. Out-of-pocket gap for adult psychiatric assessment ranges $200–$700 depending on clinician and state.

The practical takeaway: Australian women seeking an adult AuDHD diagnosis will almost certainly need two conversations with their psychiatrist, two sets of evidence, and (if presenting with anxiety or depression as many do) the patience to work past initial differential diagnoses.

Frequently asked questions about AuDHD in Australia

Is AuDHD in the DSM-5-TR?

No. The DSM-5-TR lists Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder as separate neurodevelopmental disorders. A person can be diagnosed with both simultaneously (since DSM-5, 2013), but "AuDHD" is not itself a diagnostic label.

How common is AuDHD in Australian adults?

There is no Australia-specific prevalence figure, but international meta-analyses suggest 40–50 per cent of adults with ADHD also meet Autism criteria, and approximately 30–40 per cent of autistic adults meet ADHD criteria. Extrapolating to Australia's adult ADHD population, this suggests several hundred thousand AuDHD adults nationally.

Can my GP diagnose AuDHD?

Not formally. In Australia, ADHD diagnosis is restricted to psychiatrists and (in some states) paediatricians. Autism diagnosis is typically made by a psychiatrist, paediatrician or clinical psychologist. Your GP can provide the referral, write the Mental Health Treatment Plan, and prescribe shared-care stimulant medication once a psychiatrist has initiated it.

Will I get a higher Medicare rebate for being diagnosed with both?

No. As of April 2026 there is no combined AuDHD item number on the MBS. A psychiatrist diagnosing both conditions in one appointment will still bill under the same single item as for diagnosing one.

Does AuDHD qualify for the NDIS?

Eligibility depends on functional impact, not diagnostic label. Under the 2026 NDIS reforms, autism diagnosis alone no longer guarantees access. A strong AuDHD application focuses on functional evidence: daily-living impact, executive function impact, sensory impact and employment impact, ideally with supporting reports from an OT and a psychiatrist.

What should I ask my psychiatrist at a first appointment?

Three specific questions: (1) "Given my presentation, are you screening for both ADHD and Autism, or only one?" (2) "If you identify one, what would prompt you to screen for the other?" (3) "Will your written report describe how the two interact, or will they be written up separately?"

Three policy changes we want to see

1. An integrated adult AuDHD assessment pathway recognised by RANZCP and funded by a dedicated MBS item.
2. Combined diagnostic reporting, so clinicians describe how ADHD and Autism interact in an individual rather than filing two separate paragraphs.
3. AuDHD-specific guidance for the NDIS so assessors understand that combined functional impact can exceed the sum of its parts.

Glossary

AuDHDEveryday term for co-occurring Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder. Not a formal DSM-5-TR or ICD-11 diagnosis.
DSM-5-TRDiagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision. The diagnostic reference used by most Australian psychiatrists.
ICD-11International Classification of Diseases, 11th Revision. The WHO's diagnostic system, used alongside the DSM in Australia.
IPAInterpretative Phenomenological Analysis. A qualitative research method for studying lived experience in depth.
MBSMedicare Benefits Schedule. The list of services for which Medicare pays a rebate.
RANZCPRoyal Australian and New Zealand College of Psychiatrists. The professional body that accredits Australian psychiatrists and publishes clinical practice guidelines.
Residual diagnostic categoryCraddock's term for a clinical experience that does not fit neatly into a single DSM category.

References

• Craddock, E. (2026). Navigating residual diagnostic categories: The lived experiences of women diagnosed with autism and ADHD in adulthood. Health. doi:10.1177/13634593251336163
• American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.).
• Royal Australian and New Zealand College of Psychiatrists. (2025). Australian evidence-based clinical practice guideline for ADHD.
• Australian Government Department of Health and Aged Care. (2026). Medicare Benefits Schedule. Items 291, 296, 2715, 44.
• National Disability Insurance Agency. (2026). Thriving Kids program and 2026 scheme reforms.