ADHD or autism — or both?
If you are reading this article, you are probably asking yourself exactly this question: Do I have ADHD (Attention-Deficit/Hyperactivity Disorder), Autism Spectrum Condition — or perhaps both? You are not alone. It is one of the most common questions people ask when they first suspect they might be neurodivergent.
The short answer: both are possible — and the combination of ADHD and autism (internationally referred to as AuDHD) is more common than was assumed for a long time. The longer answer deserves a careful look, because the two conditions share many features but differ clinically in important ways.
A historic shift: DSM-5 made a dual diagnosis possible
Until 2013, DSM-IV — the diagnostic manual in use at the time — applied a strict exclusion rule: if you received a diagnosis of Autism Spectrum Disorder, you could not additionally be diagnosed with ADHD. The rule was based on the outdated assumption that the two conditions must be mutually exclusive.
With the publication of DSM-5 in 2013 and later the ICD-11 by the World Health Organization, this restriction was lifted. Clinical practice now officially recognises that both conditions can coexist. This also explains why the number of dual diagnoses has risen sharply in recent years — not because more people are affected, but because diagnostics finally reflect reality.
Similarities: why the confusion makes sense
ADHD and autism are both neurodevelopmental conditions — they are present from birth and are not mental illnesses in the narrow sense. Both affect how the brain processes information, regulates attention, and responds to the environment. That is why many experiences overlap substantially.
Executive function
Both conditions involve challenges with executive function — the processes the brain uses to plan goals, set priorities, and follow through. People with ADHD and autistic people often report:
- Difficulty starting tasks (task initiation)
- Trouble keeping track of multiple commitments
- Difficulty transitioning between activities
- A sense of time that differs markedly from the norm
Sensory sensitivities
Sensory sensitivities are common in both ADHD and autism. Light, sound, fabrics, smells, or crowds can become overwhelming. In ICD-11, sensory traits are explicitly listed as diagnostic criteria for autism; in ADHD they are increasingly acknowledged in research, although they are not yet part of the formal criteria.
Emotional regulation
Emotional dysregulation — intense feeling, rapid mood shifts, difficulty recovering after stress — is common in both conditions. It is not part of the DSM-5 core criteria, but clinical research increasingly recognises it as a central feature of both.
Social fatigue
Social situations are exhausting for many people in both groups. The underlying mechanisms, however, can differ — an important point we will return to shortly.
Late diagnosis in adulthood
Both ADHD and autism are frequently overlooked in adults, especially in women, in high-functioning individuals, and in people who compensate for their difficulties through masking — the conscious or unconscious concealment of neurodivergent traits.
Differential diagnosis: the clinical differences
Despite all the similarities, the diagnostic core criteria for ADHD and autism are different. A clear distinction matters because the recommendations for therapy, support, and accommodations can differ significantly.
ADHD: attention and impulse control
The core domains of ADHD under DSM-5 (314.0x) and ICD-11 (6A05) are:
- Inattention (Criterion A1): difficulty sustaining attention over time, high distractibility, appearing not to listen
- Hyperactivity-impulsivity (Criterion A2): inner or outer restlessness, speaking without waiting, impulsive decisions
- Onset in childhood: symptoms must have been present before age 12
- Functional impairment: significant impact in at least two domains of life
Autism: social communication and repetitive patterns
The core domains of autism spectrum condition under DSM-5 (299.00) and ICD-11 (6A02) are:
- Social communication and interaction (Criterion A): differences in social-emotional reciprocity, non-verbal communication, and relationship-building
- Restricted, repetitive behavioural patterns (Criterion B): routines and rituals, intense special interests, stimming, sensory traits
- Onset in the early developmental period (Criterion C): traits must be present from birth, even if they become noticeable only later
Concrete differences in daily life
The diagnostic criteria are abstract. In everyday life the differences are often clearer — here are the most important points of comparison.
Routine and predictability
This is one of the most striking differences. People with ADHD tend to seek novelty and stimulation — routines quickly become boring and switching between projects is part of how they function. Autistic people, by contrast, seek predictability and structure — unexpected changes cause stress, and routines offer safety.
Attention patterns
Both conditions can involve hyperfocus, but in different ways:
- ADHD: hyperfocus emerges when intrinsic motivation or interest is high — it can last for hours but is hard to control deliberately
- Autism: hyperfocus often centres on stable special interests that persist for years and are explored in great depth
Social interaction
Both groups experience difficulty in social situations, but the underlying mechanism differs fundamentally:
- ADHD: impulsive interruptions, difficulty listening, spontaneous social missteps — but the underlying social "rulebook" is usually available intuitively
- Autism: uncertainty around unwritten social norms, difficulty reading non-verbal cues, exhaustion after intense social interaction despite careful preparation
Repetitive behaviours
Both groups can display physical restlessness, but with different functions:
- ADHD: fidgeting, foot tapping, twirling pens — usually a byproduct of inner restlessness
- Autism: stimming (rhythmic movements, repeated sounds, rocking) — used, consciously or unconsciously, to regulate sensory input
AuDHD: when ADHD and autism co-occur
The term AuDHD (from Autism + ADHD) has become established over recent years in both community and clinical circles to describe the simultaneous presence of both conditions. It is not an official diagnostic label — AuDHD simply means a person meets the criteria for both ADHD and autism.
What AuDHD feels like
People often describe AuDHD as an internal contradiction: the simultaneous drive for novelty (ADHD) and need for predictability (autism) can feel like pressing the accelerator and the brake at the same time. Typical experiences include:
- Needing routines but struggling to maintain them
- Intense special interests that change completely every few months
- Social exhaustion combined with an impulsive need to seek contact anyway
- Shifting between hyperfocus and complete inertia
- An apparent inconsistency that confuses outsiders — and often the person themselves
Why AuDHD is so often overlooked
AuDHD goes unrecognised for several reasons:
- Historic exclusion rule: older clinicians were trained under DSM-IV and often assign only one of the two diagnoses
- Mutual masking: autistic routines can compensate for ADHD-driven chaos, and ADHD impulsivity can cover up autistic social difficulties
- Different specialties: ADHD is often diagnosed in adult psychiatry, autism in specialised clinics — integrated assessment is rare
- Masking in women: women with both conditions often present in even more subtle ways and remain unrecognised for longer than average
Why screening both axes matters
Because ADHD and autism co-occur so often — and because their symptoms can overlap — it is not enough to examine only one axis. Someone who only takes an ADHD screening and tests negative may be missing autistic traits that would explain their difficulties. Conversely, a pure autism screening may miss the ADHD component.
What to do after the screening
An online screening does not replace a clinical diagnosis — but it can be a valuable foundation:
- Keep the result: save or print your screening report
- Talk to your GP: share the result with your family doctor or general practitioner
- Specialised assessment: seek out an adult psychiatrist with a focus on neurodivergence, or a specialised autism clinic at a university hospital
- Ask for a full assessment: if your screening suggests both axes, explicitly request an AuDHD evaluation rather than only one of the diagnoses
Also read our article on waiting times and costs for ADHD diagnosis in the DACH region — the path to clinical assessment is longer than most people expect.
Conclusion: both axes deserve attention
The question "ADHD or autism?" is often the wrong one. The clinically meaningful question is: "Which traits from each axis show up for me — and in what combination?" If you are asking that question, you have already taken the most important step: being willing to understand your own experience in a differentiated way.
Go deeper: What is neurodivergence? — an overview of the full spectrum. If you are interested in women-specific aspects, we recommend autism in women and ADHD in adults.