Can ADHD and Autism Coexist in One Person?
Yes, ADHD and autism can absolutely coexist. This is known as a dual diagnosis or co-occurrence of ADHD and autism, and it is far more common than many people realise. Recent research shows that up to 50–70% of autistic individuals also meet the criteria for ADHD, a formal recognition first made in the DSM-5 in 2013 PubMed.
At the Autism and ADHD Diagnostic Centre (AADC), we regularly assess both children and adults who may show overlapping symptoms. Many people come to us after already being diagnosed with one condition, but continue to face challenges related to another.
This blog will explain:
- The core symptoms of ADHD and autism are individually
- How the two conditions often coexist
- The diagnostic criteria for each
- What dual diagnosis looks like in children and adults
- NICE-aligned assessment pathways
- Support and treatment strategies for managing ADHD and autism
What Is Attention Deficit Hyperactivity Disorder (ADHD)?
ADHD is a neurodevelopmental condition characterised by symptoms of inattention, hyperactivity, and impulsivity. It affects both children and adults, although symptoms can present differently depending on age.
ADHD is typically divided into three presentations
- Inattentive – forgetfulness, disorganisation, daydreaming
- Hyperactive-Impulsive – fidgeting, restlessness, blurting out
- Combined – a mix of both symptom types
According to NICE NG87 guidelines, diagnosis of ADHD must include informant interviews, structured diagnostic tools (e.g. DIVA-5), and developmental history NICE NG87. Children with ADHD often have difficulty regulating their attention and may be labelled disruptive. Adults with ADHD may experience burnout, emotional overwhelm, and career instability.
What Is Autism Spectrum Disorder (ASD)?
Autism, or Autism Spectrum Disorder (ASD), is a developmental condition that affects how individuals experience the world and relate to others. Symptoms vary widely but often include:
- Social communication challenges
- Repetitive behaviours and routines
- Sensory sensitivities
- Intense focus on specific interests
Children with autism may struggle with transitions, loud environments, or group play. Adults with autism may report exhaustion from masking symptoms or avoiding sensory overload.
Diagnosis of autism also requires the use of tools like ADOS-2, DISCO, or ADI-R, in line with NICE CG142 guidelines. Autistic spectrum disorder symptoms can overlap with ADHD, making accurate assessment vital.
Autism and ADHD: Shared Traits and Distinct Presentations
ADHD and autism are distinct conditions, but many symptoms often coexist, particularly around executive function, emotional regulation, and sensory sensitivity.
| Trait | ADHD Symptoms | Autism Symptoms | Dual Diagnosis Approach |
| Executive Function | Forgetfulness, procrastination | Rigid routines | Blended tech tools + structured flexibility |
| Sensory Regulation | Often not a core trait | Strong sensitivity to stimuli | Sensory diets + movement breaks |
| Social Communication | Blurting, interrupting | Difficulty reading social cues | Social coaching + peer modelling |
Core symptoms of ASD and ADHD can overlap, especially in children and adolescents, making it difficult to distinguish one from the other. For example, a child may be inattentive in school due to ADHD or overwhelmed by noise due to autism, or both.
According to ScienceDirect, co-occurrence should be actively screened for to prevent misdiagnosis.
Diagnosis and Treatment of Coexisting Conditions
The diagnostic criteria for autism and ADHD are clearly outlined in NICE guidelines, which AADC strictly follows. Our assessments are recognised by the NHS, schools, and GPs.
For Children with ADHD and ASD
- Developmental history, school input, and play-based assessments
- Use of tools such as Young DIVA and ADOS-2
- Involvement of multidisciplinary clinicians
For Adults with ADHD and Autism
- Pre-screening and structured interviews (DIVA-5, DISCO)
- Optional attention testing
- Multi-clinician diagnostic panel
We also support patients via Right to Choose (for ADHD only) in England.
Why Does a Dual Diagnosis Matter?
When individuals with ADHD and autism are not correctly diagnosed, support may all short:
- Medication for ADHD may be prescribed without accounting for sensory needs.
- Social skills training may help in autism but ignore impulsivity.
Some people are diagnosed with ASD also meeting criteria for ADHD, but treatment must be adjusted accordingly. Studies confirm that autistic people with ADHD often face higher anxiety and risk of burnout.
Autism also meets the criteria for ADHD in many individuals, but that is often missed due to masking, especially in girls.
Research Spotlight: UK Expert Consensus
“2024 UK Consensus: Dual diagnosis requires integrated ADHD and autism screening to avoid missed traits in females.”
Long NHS waits have pushed families and adults toward private assessments. Over 212,000 people are waiting for autism diagnosis in England, and adult ADHD assessments can take over 8 years Children’s Commissioner.
Myths About the Coexistence of ADHD and Autism
Myth: ADHD and autism cannot co-occur.
Fact: DSM-5 and NICE guidance both confirm the validity of dual diagnosis.
Myth: ADHD only affects children.
Fact: ADHD symptoms persist into adulthood and often worsen without support.
Myth: All ADHD symptoms mean someone is impulsive.
Fact: Not always. Some people with ADHD are more inattentive than hyperactive.
Myth: ADHD medication is harmful for autistic people.
Fact: It depends on the profile. Some benefit greatly, especially when sensory needs are managed.
What Support Is Available for People with ADHD and Autism?
ADHD Treatment Options
- CBT and coaching
- Medication when appropriate
- Occupational therapy for executive function
Autism-Focused Support
- Sensory integration therapy
- Peer support groups
- Visual schedules and environment adjustments
For Dual Diagnosis
- Multimodal treatment plans
- Personalised strategies based on core symptoms
- Family education and support networks
Lived Experience with Dual Diagnosis (AuDHD)
“I was diagnosed with ADHD as a teen. But it was not until my 30s that I discovered I was also autistic. Everything suddenly made sense.” – AADC client
We often hear similar stories from individuals with both ADHD and autism, especially adults who felt misunderstood for decades. Early intervention for children with ADHD and autism makes a significant difference.
FAQs: ADHD and Autism Spectrum Disorder
Can ADHD and autism co-occur in children and adults?
Yes. It is called AuDHD, and it is increasingly recognised in clinical settings.
What are the symptoms in children with ADHD?
Restlessness, difficulty focusing, and impulsive behaviours.
Is autism diagnosis different for children than adults?
Yes. Children require input from schools, while adults may undergo tools like DISCO or ADOS-2.
What if ADHD is diagnosed alone?
Support may not address masking, burnout, or sensory overload.
Are assessments recognised by the NHS?
Yes, if they follow NICE protocols. AADC reports meet these standards.
Final Thoughts on Managing ADHD and Autism
Dual diagnosis is not rare. It is manageable, with the right help.
AADC provides integrated, NICE-aligned assessments for ADHD and autism across the UK. We understand the lived experience, the research, and the urgency.
Get in touch for a free consultation or visit autismandadhddiagnosticcentre.com to find support today.
