Given the ongoing normalisation of neurodivergent conditions, it might be hard to believe, but before 2013, doctors were not allowed to diagnose both autism spectrum disorder (ASD) and ADHD in the same person.

Despite there being a clear overlap in symptoms, as well as significant rates of co-morbidity observed in clinical settings between autism and ADHD, a dual diagnosis was not considered to be medically appropriate.

A recent study involving 5,504 adults has shed new light on the overlap between these two conditions in adults, addressing how they both manifest independently and overlap with one another.

And whilst it does lean heavily – and accurately – into framing both conditions as requiring their own diagnosis, it did reveal some fascinating insights as to how these conditions interact with one another.

This research is also particularly significant as it focuses on adults, whereas most previous studies only concentrated on children and adolescents.

Let’s take a look at how both conditions can exist with one another, as well as potentially create some confusion in the way they overlap with one another.

The Hidden Complexity of Autism and ADHD Overlap in Adults

One of the biggest issues in the overlap between autism and ADHD when they co occur with one another is the push and pull effect created between the core symptoms of each condition.

For example, what this might look like in the real world is a conflict in how you would approach the need for routine and structure.

In a traditional autistic support structure, there might be a need for systemising and creating step-by-step routines which might be counter to the ADHD tendency that leans towards craving novelty, making it extremely difficult to be productive in home or working environments.

Your autistic traits may cause you to extensively script and role-play every last detail before visiting somewhere new.

You might need to know everything there is to know to regulate your nervous system enough to alleviate the anxiety in order to put yourself in unfamiliar situations.

In turn, this might prevent you from having new experiences in a singular diagnosis of autism.

However, when ADHD is present, the overwhelming need to experience novelty creates that pulling to experience the unknown. The big ‘What if?’

And so, this can lead to an outward appearance of being able to manage social situations and new experiences like anyone else, while internally keeping mental checks and balances, masking your anxiety and trying to keep your cool.

Constantly balancing the autistic need for predictability with ADHD’s craving for stimulation, never quite settling into a routine that satisfies both needs.

How ADHD and Autism Mask Each Other

In a singular diagnosis of ADHD, social difficulties are usually rooted in impulsivity and inattention, which can lead to interrupting conversations and missing key social cues due to distraction.

On the other hand, the social challenges experienced in autism arise from fundamental difficulties in understanding and processing sensory input on both a linguistic and subtextual (abstract) level.

And so, when both conditions are present, the ADHD symptoms can often be overshadowed by the more subtle, social communication difficulties, which is a main characteristic of autism.

For example, ADHD’s tendency towards excessive talking might mask the autistic challenges of social reciprocity, while the rigid behavioural patterns which are characteristic of autism could mask some of the hyperactivity of ADHD.

What is Autism and ADHD Combined Called?

In recent years, the term AuDHD has been gaining significant traction to describe the overlap between autism and ADHD. However, despite it getting substantial uptake within popular culture, it isn’t yet recognised within the DSM.

It’s one of those strange grey areas where the research hasn’t quite fully caught up with what people are experiencing in the real world, which is simply the nature of psychology. 

There needs to be a great weight of evidence and research before new terminology can be answered into canon – if it is ever included at all. Obviously, to ensure proper due diligence has been carried out.

It wasn’t until 1980 that autism itself was included officially with the DSM III. 

Even when individuals don’t meet the full diagnostic criteria for both conditions, they often display below-threshold symptoms of the other condition.

Signs, Symptoms, and Traits of Autism and ADHD Overlap

Learning the symptoms of a mental health condition is essentially becoming aware of its language. Over time, as you recognise more of the patterns at play, you’re then able to replace these patterns with more constructive choices.

But to do so, requires a greater degree of presence and mindfulness – a greater quality of discernment. Being the active participant, instead of the passive bystander.

Asking questions such as, “Is this really how I truly desire to be in this moment? Is there a greater choice for me?”

And by doing so, by really being with yourself, those previously elusive symptoms become more apparent and recognisable.

The language of your own neurodivergent mind becomes less of an obstacle, and there is a greater acceptance of the self and quality of responsibility you’re being called into.

At first, the patterns might seem chaotic or confusing. But as you develop your awareness, you begin to recognise the subtle signals your brain sends you.

This, then, leads to empowerment. 

Because when you can identify your patterns early, in a proactive sense, rather reactive sense, it makes choices feel like that coming from you and a place of creation, rather than defending yourself against anything which might be perceived as bad or wrong from within.

The real key here is engaging in patient observation – in non-judgement.

And as you develop this skill, you create a better relationship with yourself.

This increased awareness then becomes a powerful foundation for self advocacy.

Social Communication Challenges in ADHD and Autism Overlap

Social communication challenges are at the heart of many mental health disorders. And those communication challenges have distinct manifestations in both autism and ADHD. 

We rely on our social skills in order to connect with one another, and so when they’re compromised, the quality of our human experience often suffers as a result.

Let’s take a closer look.

Understanding the Core Differences

Performance-Based Challenges:

Within the symptom set of ADHD, social difficulties usually arise from impulsivity and potential issues rather than the lack of understanding often seen in autism. It might be that you know exactly what you should say, or do in social situations, but you find yourself unable to consistently apply this knowledge in real time interactions..

Social Processing Variations:

The traits of neurodivergence common to autism affect how social information is both received and understood at a basic level. So this includes challenges such as interpreting body language, understanding social context, and responding to non-verbal communication cues.

Real-World Manifestations:

The overlap and commodity between autism and ADHD creates a dynamic where you might have a very strong intellectual understanding in relation to social etiquette (ADHD). However, given your fundamental processing challenges (autism), you might struggle to apply your knowledge naturally, in conversation.

ADHD Social Communication Patterns

• There might be an excessive impulsivity in conversations with peers
• Social cues can often be missed due to inattentiveness
• Individuals might engage in a stream of consciousness narrative (excessive talking)
• There may be an impact on self-esteem due to an inability to integrate in social circles

Autism Social Communication Patterns

• There may be varying levels of challenge with subtextual/non-verbal communication styles
• Individuals could experience difficulty in reciprocal exchange in conversation
• Certain abstracts social concepts might be hard to comprehend
• There may be an over reliance on social scripting to navigate relationships

Attention Control and Hyperactivity

Attention Control Challenges

Individuals with both autism and ADHD experience difficulties with attention control, but for different reasons:

• ADHD: Attention difficulties within ADHD are often characterised by being easily distracted, which can lead to procrastination and difficulty in effective task management. 
• Autism: On the other hand, autistic individuals are quite often able to exhibit hyper focus within special areas of interest with the challenge for them being transitioning focus.

Hyperactivity Manifestations

While hyperactivity is more commonly associated with ADHD, it can present in both conditions:

• ADHD: This can often be seen as physical restlessness, which might manifest as fidgeting or difficulty remaining still for extended periods.
• Autism: Autistic individuals may engage in involuntary repetitive movements, such as stimming or hand flapping. Although this is typically seen in severe cases of autism and less so in high functioning autistic adults.

Shared Traits

Some attention control and hyperactivity traits overlap in both conditions:

• Executive function deficits: Both individuals with ADHD and autism can struggle with the initiation and completion of tasks and activities.
• Sensory processing: Heightened reactivity to external stimuli can impact attention and mental and emotional capacity within both ADHD and autism.
• Social interactions: Difficulties with attention can affect individuals with both autism and ADHD.

Sensory Sensitivities and Repetitive Behaviours

Distinct Sensory Profiles: Although both ADHD and autism present with sensory challenges, autism is characterised by difficulties in general sensory processing, whilst ADHD is known for the difficulties in filtering the amounts of sensory information. i.e taking on too much at once.

Autism-Specific Sensitivities: Autistic individuals experience both hypersensitivity and hyposensitivity to sensory input. This can relate to responses of all external stimuli, including light, sound, textures, and smells. 

ADHD Sensory Challenges: In ADHD, sensory issues arise from difficulty in filtering information, which can lead to the classic symptom of ADHD overwhelm in overly stimulating environments or exchanges.

Combined Impact: When both conditions are present, sensory challenges can become much more difficult. You might experience autism’s fundamental sensory sensitivities, as well as ADHD’s difficulty in filtering sensory input, creating increased vulnerability to sensory overload.

Behavioural Responses: These sensory differences often manifest in repetitive behaviours – either as self-soothing mechanisms in autism or as responses to under stimulation in ADHD.

Real-World Examples of Autism and ADHD in Adults

As you begin to become more aware of how both autism and ADHD intersect with one another on the symptom level, influencing your choices and actions, it enables you to make more meaningful changes in your life.

If you take the analogy of your daily choices contributing to an unfolding story.

Each story you are playing out is made up of a series of patterns.

By developing the skill of discernment, you can become more mindful of these cycles of behaviour, and engage in what is called pattern interruption.

And so, instead of fighting your natural tendencies, you can begin to work with them.

This then leads to a greater sense of self efficacy and empowerment, transforming what were once frustrating limitations into an opportunity for growth.

So you’re no longer in a mode of reactivity, at the mercy of your competing needs.

And instead, you are actively taking control of your narrative and moulding your life to suit your strengths relating to your specific neurodivergence.

ADHD and Autism Overlap in Females

For women, who experience both autism and ADHD, the experience has often been likened to trying to live two, contrasting lives at the same time.

Many women describe spending years, even decades, feeling “different” without understanding why, masking their true personality.

And this is due to the presentation of both conditions in women being so subtle. So much so, they can go undetected, and therefore undiagnosed, until much later on in adulthood.

Conversely, at least in the case of ADHD, pre-adolescent boys might show more obvious signs of hyperactivity, whilst girls often tend to exhibit symptoms of inattentiveness, and will internalise their struggles.

This might result in excelling academically, whilst at the same time, battling exhaustion from masking their symptoms.

Many report being labeled as “shy,” “dramatic,” or “too sensitive” when actually dealing with sensory overwhelm and social processing difficulties.

Women who present with both conditions also describe simultaneously craving social connection while finding it overwhelming, or being extremely organised in some areas while struggling with basic daily tasks.

Unfortunately, under diagnosis is a fairly common scenario, with many women only discovering the nature of their neurodivergence, after an episode of burnout or once their anxiety becomes unbearable.

ADHD and Autism Overlap in The Real World

The following real-world examples illustrate how the internal conflict between the autistic mind that craves routine and the ADHD mind craves novelty and spontaneity manifests in everyday situations, highlighting both the challenges and the creative adaptations people develop to manage them.

The Meeting Room Dilemma

Sarah is an office worker who struggles in team meetings as well as with the office environment. The forwardness of her ADHD empowers her to contribute enthusiastically, which is sometimes not received in the greatest way when she interrupts people – although she remains a valued member of the team. But in addition to this, her hypersensitivity to light background noise makes it difficult to focus. Despite her creating detailed meeting notes to help her remain present, she frequently misses social cues from her colleagues, when she’s absorbed and her note taking process..

The Organised Chaos

Michael’s work desk often appears chaotic to anyone who wanders by. He has papers and documents scattered everywhere. However, he keeps an incredibly well organised digital calendar, which allows him to locate any document instantly using a complex system of organisation which is tailored to his particular neurodivergent thinking style. His ADHD tendencies create surface disorder, while his autistic tendency toward systemising helps him maintain precise digital organisation.

The Social Battery Paradox

Emma loves socialising. She makes very quick and spontaneous plans due to her ADHD tendencies that steer her towards a desire for novelty and stimulation. However, she is often known to cancel at the last minute when her autistic symptoms create sensory overload, which can sometimes lead to shutdowns. This is the brain signalling that it doesn’t have capacity to receive any more external stimulus. And so, as a result, she’s developed a strategy of scheduling shorter meetings, often one-on-one with people at familiar cafés, where she knows she won’t be overstimulated.

The Routine Revolution

James is someone who has traditionally struggled with his morning routine. This has led to him creating step-by-step structures to satisfy his autistic need for predictability and regularity. However, he rarely sticks to the same routine for very long. After about three weeks or so, his ADHD mind, which craves novelty, drives him to completely restructure his morning. The way he wakes up, his self care practices, his hygiene etc. He will often keep the same structure, but replace the component parts to keep things novel and engaging.

The Special Interest Cycle

Lisa’s passion for astrology has been a constant for many years (autism). However, the way she engages with it frequently changes (ADHD). One month, she might be interested in exploring her natal chart, the next month she might be interested in engaging in the astrology which is unfolding in real time, listening to her favourite presenters on YouTube or podcasts. She remains engaged with the subject, but has a very nonlinear way of exploring her passion.