AuDHD in Adults: What it means when ADHD and autism co-occur

Many of the adults I work with arrive at their first appointment with a familiar story.

They have spent years moving between ADHD strategies and autistic ones and noticing that nothing quite fits. The productivity systems that work for ADHD friends feel rigid and overwhelming within days. The structure and predictability that suit autistic friends start to feel constraining within a week. People describe themselves as walking contradictions. Deeply focused yet constantly distracted. Craving routine yet bored by it. Wanting connection yet exhausted by company.

This is the lived experience of AuDHD. For adults who fit this pattern, recognition often arrives later in life and brings with it a complicated mix of relief and grief.

What AuDHD means

AuDHD describes the co-occurrence of Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder in the same person. The term has emerged from the neurodivergent community over the past decade and is now widely used in clinical practice. Until 2013, the diagnostic system did not allow a person to receive both diagnoses. The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) removed that exclusion, and clinicians can now diagnose both conditions where the evidence supports them.

Estimates of how often the two conditions co-occur vary depending on the population studied and the methods used. Across a range of studies, between 30 and 80 percent of autistic adults show clinically significant ADHD features, and a substantial proportion of adults with ADHD show clinically significant autistic traits (Hours, Recasens, & Baleyte, 2022; Antshel & Russo, 2019). The overall picture is that overlap is the norm rather than the exception, and that anyone presenting for assessment of one condition should be screened carefully for the other.

The internal tension that defines AuDHD

People with AuDHD often describe a particular kind of internal pull that neither autistic adults nor ADHD adults on their own typically describe. The two neurotypes generate opposing preferences that the same person carries simultaneously.

The autistic side tends to seek predictability, depth, sensory regulation, and time alone in a low-stimulation environment to recover. The ADHD side tends to seek novelty, stimulation, variety, and the dopamine of new projects, ideas, and people. The result is a pattern that includes starting and abandoning routines, building elaborate systems then ignoring them, planning predictable weeks then sabotaging them with last-minute changes, and craving solitude immediately after seeking out company.

Holding two opposing drive systems at once produces a predictable kind of internal friction. People who recognise this pattern often describe an exhaustion that neither autism nor ADHD on its own would explain. The tension is a feature of the neurotype, and the work of adapting to it is the work of learning what each side needs and when.

In clinical practice, the AuDHD pattern often shows itself most clearly through the contradictions people describe when asked what their ideal week would look like. Many AuDHD adults describe wanting two ideal weeks that cannot exist at the same time.

Why AuDHD often goes unrecognised in adults

The historical picture of autism and ADHD was built largely on observations of young boys, and the diagnostic systems still carry that legacy. Adults who do not fit the stereotypical childhood profile, and women and gender-diverse adults in particular, are routinely missed.

Masking compounds the problem. Many AuDHD adults learn early that their natural responses attract criticism, and they spend years studying how other people behave so they can mimic it. They suppress stimming, rehearse social scripts, force eye contact, and observe themselves in conversation the way an actor watches a performance. The cumulative impact of masking is significant. Long-term camouflaging is associated with chronic exhaustion, anxiety, depression, identity confusion, and what is often described as autistic burnout, a state of cognitive and emotional collapse that can take months or years to recover from (Hull et al., 2019; Cassidy et al., 2018).

For many adults, the unmasking comes at a predictable point. A major life event, the demands of parenthood, perimenopause, a workplace change, or the cumulative weight of years of compensation can erode the capacity to keep masking. The person who has functioned passably for decades suddenly cannot. What looks like a sudden breakdown is often the visible end of a longstanding pattern.

How AuDHD presents in adults

The clinical picture varies considerably between individuals, but several themes appear consistently.

People often describe being seen as gifted in some areas and inexplicably struggling in others. They may have built a career around their strengths while quietly drowning in tasks that others appear to find straightforward. Opening mail, scheduling appointments, returning calls, and maintaining a consistent eating and sleeping pattern can become significant daily challenges. Many AuDHD adults have intense focused interests that look like passions to others and feel essential to regulation from the inside.

Sensory sensitivities are common and often hidden. Many AuDHD adults have learned to tolerate environments that significantly distress their nervous system and only recognise the cost when they reach the safety of their own home. Fluorescent lighting, certain fabrics, perfume, background noise in cafes and open-plan offices, and the smell of food cooking can all be sources of low-grade overload that compound over the course of a day.

Emotional intensity tends to run high. People describe being deeply moved by music, art, animals, and injustice, and equally affected by criticism, rejection, and conflict. Rejection sensitive dysphoria is frequently described and can be one of the more distressing features of the adult AuDHD experience.

Executive function difficulties usually show a particular pattern. Planning and flexibility tend to be more affected by the autistic dimension. Behavioural regulation, sustained attention, and task initiation tend to be more affected by the ADHD dimension. The Executive Skills Questionnaire-Revised, used in adult ADHD assessment, has been shown to differentiate these profiles, and the pattern of difficulty across domains supports the clinical formulation (Craig et al., 2016).

Sleep is often a longstanding difficulty. People describe a brain that does not switch off, sensory issues that interfere with falling asleep, and a body clock that resists conventional timing.

Why the female and non-binary presentation is often missed

The autism diagnostic instruments developed during the 1990s and 2000s were validated primarily on male samples. Observational tools such as the Autism Diagnostic Observation Schedule (ADOS-2) have reduced sensitivity for females, particularly those who mask effectively (Rea et al., 2023; Kamp-Becker et al., 2018). Women and gender-diverse adults are more likely to have learned to suppress visible autistic behaviours, to engage in deep social study and rehearsal, and to present at assessment with the very compensatory strategies that hide the diagnosis.

In my practice, I use the MIGDAS-2 (Monteiro Interview Guidelines for Diagnosing Autism Spectrum) as the primary diagnostic interview for adult autism because its narrative interview format draws out the internal experience and the masking history that observational tools tend to miss. The MIGDAS-2 is used alongside questionnaire measures that specifically assess camouflaging, including the Camouflaging Autistic Traits Questionnaire (CAT-Q).

For ADHD, the diagnostic interview is the DIVA-5 (Diagnostic Interview for ADHD in Adults), which covers the DSM-5 criteria across the lifespan and includes structured questions about functional impairment. Where AuDHD is suspected, both interviews are conducted, and the formulation considers both diagnoses together.

What the assessment process involves

A thorough adult AuDHD assessment typically takes between four and six sessions.

The process includes the following components.

• A comprehensive developmental history covering childhood, education, social development, employment, relationships, sensory experiences, and prior mental health presentations.

• Standardised questionnaires administered before the clinical interview, including measures of autistic traits, ADHD symptoms, executive function, sensory profile, and common comorbidities.

• The DIVA-5 structured diagnostic interview for adult ADHD.

• The MIGDAS-2 narrative diagnostic interview for autism.

• Cognitive assessment where it is clinically indicated, typically using the WAIS-5 with selected D-KEFS subtests.

• Adaptive functioning assessment where it is relevant, typically using the ABAS-3.

• Collateral information where available and consented, including school reports, family informant interviews, and prior assessments.

  
  

The aim is not to slot the person into a category. It is to develop a formulation that accounts for the lifelong pattern, identifies specific support needs, and gives the person an accurate framework for understanding their own experience.

After the diagnosis

A late AuDHD diagnosis is a significant life event, and the period after it deserves dedicated clinical attention. Most people experience some combination of relief, grief, anger, and a reorganisation of how they understand their own history. The relief comes from finally having a framework that fits. The grief comes from the years lived without that framework, and from imagining what life might have been like with earlier recognition. The anger often surfaces toward systems and individuals that missed the diagnosis or attributed the difficulties to character flaws.

Practical work after diagnosis often includes the following areas.

• Reducing the demand on masking, which often involves changes at work, in relationships, and in social commitments.

• Developing sensory and executive function supports that suit the specific profile, rather than generic strategies designed for a single neurotype.

• Addressing comorbidities that may have developed during the unmasked years, including anxiety, depression, complex trauma, eating difficulties, and burnout recovery.

• Engaging with neurodivergent community resources where the person wishes, including Reframing Autism, Yellow Ladybugs, ADHD Australia, and the lived-experience literature.

• Identifying and requesting workplace accommodations where they are appropriate.

• Considering medication for the ADHD dimension where it is indicated, in collaboration with a prescribing clinician.

The work centres on building a life that fits the neurotype rather than working against it. It rarely involves trying to change the neurotype.

When to consider an assessment

People often ask how certain they need to be before they pursue an assessment. The threshold is lower than most assume. If the lifelong pattern feels recognisable, if the description in this article resonates, and if the difficulties are affecting work, relationships, or wellbeing, an assessment is a reasonable next step. The assessment process itself is what determines whether the diagnostic criteria are met.

Most people who pursue assessment describe relief at having a definitive answer in either direction. A diagnosis provides a framework and access to specific supports. A negative finding still provides clarity, often alongside identification of other contributing factors such as trauma, anxiety, or executive function difficulties that can be addressed in their own right.

Frequently asked questions

What does AuDHD stand for?

AuDHD is the informal term used to describe the co-occurrence of autism (Au) and ADHD in the same person. It is not a separate diagnosis. Each condition is diagnosed independently using DSM-5-TR criteria, and the AuDHD label captures the combined clinical picture.

Can a person have both ADHD and autism?

Yes. The DSM-5, published in 2013, removed the prior diagnostic exclusion that prevented a person from receiving both diagnoses. Adults can be assessed for and diagnosed with both conditions where the clinical evidence supports them.

How common is AuDHD in adults?

Co-occurrence rates vary across studies. Research consistently identifies substantial overlap, with between 30 and 80 percent of autistic adults showing clinically significant ADHD features, and a substantial proportion of adults with ADHD showing clinically significant autistic traits. The variation in estimates reflects differences in study methodology, sample composition, and the screening tools used.

What are the signs of AuDHD in adults?

Common signs include a longstanding pattern of contradictory preferences (predictability paired with novelty-seeking), executive function difficulties affecting planning and follow-through, sensory sensitivities, intense focused interests, social exhaustion from masking, emotional intensity, rejection sensitivity, sleep difficulties, and a sense of having moved between ADHD and autism descriptions without either feeling like a complete fit.

How is AuDHD diagnosed in Australia?

In Australia, an adult AuDHD assessment is typically conducted by a psychologist or psychiatrist with experience in neurodevelopmental assessment. The process includes a developmental history, standardised questionnaires, structured diagnostic interviews (the DIVA-5 for ADHD and the MIGDAS-2 for autism are preferred at Behavioural Edge Psychology), and where indicated, cognitive and adaptive functioning assessment. A formal diagnosis is required to access many supports, including ADHD medication, NDIS funding (where eligibility criteria are met), and workplace accommodations.

Is AuDHD a recognised diagnosis under the NDIS?

NDIS access is determined by functional impact rather than by diagnosis alone. Autism at Level 2 or above is included on the NDIS List A, which provides streamlined access. ADHD is not on List A, but functional capacity evidence can support a Section 24 access application where the impact on daily functioning is substantial and permanent. AuDHD presentations are assessed in line with the same functional capacity framework.

How long does an adult AuDHD assessment take?

A comprehensive adult AuDHD assessment typically requires between four and six clinical sessions, plus completion of online questionnaires in advance and a written report following the final session. The full process generally takes between four and eight weeks from initial appointment to receipt of the report.

Where to next

If anything in this article resonates, several useful next steps are available. Reading the Australian neurodivergent community literature can support self-understanding before deciding whether to pursue formal assessment. Speaking to a GP about a referral pathway can help clarify what is involved. Booking an initial consultation with an experienced clinician can answer specific questions about the assessment process.

At Behavioural Edge Psychology, I work with adults presenting with suspected ADHD, autism, and AuDHD using the MIGDAS-2, DIVA-5, and NovoPsych psychometric battery, alongside cognitive and adaptive functioning assessment where it is indicated. The practice is adults-only and neurodiversity-affirming, with particular experience in the female and non-binary adult presentation. Consulting rooms are located at Caulfield South and St Kilda in Melbourne, with telehealth available across Australia.

People who would like to discuss whether an assessment might be useful are welcome to make contact via the practice website or by phone. The conversation does not commit anyone to assessment, and an initial discussion can help clarify whether the process is the right next step.

References

• Antshel, K. M., & Russo, N. (2019). Autism spectrum disorders and ADHD: Overlapping phenomenology, diagnostic issues, and treatment considerations. Current Psychiatry Reports, 21(5), 34.

• Cassidy, S., Bradley, L., Shaw, R., & Baron-Cohen, S. (2018). Risk markers for suicidality in autistic adults. Molecular Autism, 9, 42.

• Craig, F., Margari, F., Legrottaglie, A. R., Palumbi, R., De Giambattista, C., & Margari, L. (2016). A review of executive function deficits in autism spectrum disorder and attention-deficit/hyperactivity disorder. Neuropsychiatric Disease and Treatment, 12, 1191-1202.

• Hours, C., Recasens, C., & Baleyte, J. M. (2022). ASD and ADHD comorbidity: What are we talking about? Frontiers in Psychiatry, 13, 837424.

• Hull, L., Mandy, W., Lai, M. C., Baron-Cohen, S., Allison, C., Smith, P., & Petrides, K. V. (2019). Development and validation of the Camouflaging Autistic Traits Questionnaire (CAT-Q). Journal of Autism and Developmental Disorders, 49(3), 819-833.

• Kamp-Becker, I., Albertowski, K., Becker, J., Ghahreman, M., Langmann, A., Mingebach, T., Poustka, L., Weber, L., Schmidt, H., Smidt, J., Stehr, T., Roessner, V., Kucharczyk, K., Wolff, N., & Stroth, S. (2018). Diagnostic accuracy of the ADOS and ADOS-2 in clinical practice. European Child & Adolescent Psychiatry, 27(9), 1193-1207.

• Rea, H. M., Webb, S. J., Kurtz-Nelson, E. C., Hudac, C. M., Bernier, R. A., Wensel, A., Boyd, B. A., Eichler, E. E., & Earl, R. K. (2023). Sex differences on the ADOS-2. Journal of Autism and Developmental Disorders, 53(7), 2878-2890.

About the author

Dr Sarah Fischer is Principal Psychologist and Director of Behavioural Edge Psychology Pty Ltd, with consulting rooms in Caulfield South and St Kilda, Victoria. She holds a PhD in Psychology, a Master of Psychology, and is registered with AHPRA (PSY0001719709) with endorsement in organisational psychology. She is a Member of the Australian Psychological Society (MAPS) and the Australian Association of Psychologists Inc (AAPi). Her practice focuses on adult neurodevelopmental assessment, complex trauma, workplace psychology, and legal sector wellbeing.