Autism vs ADHD: Understanding the Key Differences

Estimated reading time: 5 minutes

• Introduction
• What are the similarities between autism and ADHD?
• What are the main differences?
  • Core features
  • Social intent vs social skill
  • Patterns of behaviour
  • Developmental profile and diagnosis
• Can someone have both conditions?
• How is each diagnosed?
  • Common assessment elements
  • Where to start
• What does this mean for support and treatment?
• Practical next steps
• Summary

Introduction

Autism and ADHD are two commonly discussed neurodevelopmental conditions. While they can share traits and sometimes look similar on the surface, they are distinct in important ways. This guide explains the similarities and differences, answers common questions like “autism or ADHD?” and “can someone have both conditions?”, and points you toward practical next steps for assessment and support.

What are the similarities between autism and ADHD?

Although autism and ADHD are different diagnoses, they do overlap in several areas—this is often why people ask “autism vs adhd” when trying to understand behaviour. Key similarities include:

• Attention and focus differences: People with either condition may struggle with concentrating, switching attention, or prioritising tasks.
• Social challenges: Difficulties with social interaction or reading social cues can occur in both, though the reasons may differ.
• Sensory sensitivities: Over- or under-sensitivity to sounds, textures, lights, or smells can be present in both conditions.
• Executive function differences: Planning, organisation, time management and working memory challenges are common.
• Co-occurring mental health issues: Anxiety, depression and sleep problems can affect people with either diagnosis.

These overlapping traits contribute to diagnostic complexity and are why a careful assessment is important before concluding whether someone has autism, ADHD, both, or neither.

What are the main differences?

Understanding the core differences helps clarify the question “difference between autism and adhd.” Here are the main distinctions:

Core features

• Autism: Primarily involves persistent differences in social communication and interaction, along with restricted, repetitive behaviours or highly focused interests.
• ADHD: Defined by patterns of inattention, hyperactivity, and impulsivity that are developmentally inappropriate and impairing.

Social intent vs social skill

• Autism: Social communication differences often reflect a different way of perceiving and processing social information—difficulty intuitively understanding implied social rules.
• ADHD: Social problems more often stem from impulsivity, distractibility, or missing social cues because of inattention, rather than a fundamentally different style of social processing.

Patterns of behaviour

• Autism: May show repetitive routines, insistence on sameness, and intense interests.
• ADHD: Tends to show variability in activity level and attention—more fluctuation than rigid routine.

Developmental profile and diagnosis

• Autism: Diagnostic criteria emphasise social communication differences and restricted/repetitive behaviours, typically noticed in early childhood but sometimes recognised later.
• ADHD: Diagnosis focuses on attention and activity symptoms that are present across settings (home, school, work) and typically become noticeable in early school years.

Can someone have both conditions?

Yes. Co-occurrence of autism and ADHD is common. Many people receive both diagnoses, and research shows significant overlap between the two conditions. When both are present, the individual may experience combined challenges—such as intense interests and sensory needs from autism alongside inattention and impulsivity from ADHD—which can complicate daily life and mask one condition behind the other.

Because the combination can change how symptoms present and respond to strategies or treatments, multidisciplinary assessment and a nuanced approach to support are important.

How is each diagnosed?

Diagnosis is a clinical process based on history, observation, and standardised information from multiple sources. Although the steps overlap, the focus differs depending on whether autism or ADHD is being assessed.

Common assessment elements

• Clinical interview: A detailed developmental and current history from the individual and family.
• Behavioural observations: Structured and unstructured observation in clinic and reports from home, school or workplace.
• Rating scales and questionnaires: Standardised tools capture symptom patterns, severity and impact across settings. (For adults, tools such as the RAADS-R help screen for autism; for ADHD, adult and child rating scales are used.)
• Cognitive and educational assessment: When learning or intellectual differences may be relevant.
• Multi-disciplinary input: Psychologists, psychiatrists, paediatricians, occupational therapists and speech and language therapists can contribute.

Where to start

If you’re wondering “autism or adhd?”, online screening tests can be a useful first step to see whether a formal assessment is warranted. (NeuroDirect’s online ADHD screening tests and NeuroDirect’s online autism RAADS-R test.) For formal diagnosis you’ll usually be referred to specialist services via your GP or a private clinician, depending on your local pathway.

For reputable overviews of what a formal diagnostic pathway might look like, see NHS information on autism and basic CDC ADHD guidance.

What does this mean for support and treatment?

Support and treatment should be personalised, workplace- or school-informed, and flexible to changing needs. Key principles include:

• Individualised plans: Assessments should guide tailored supports that address both strengths and needs.
• Environmental adjustments: Sensory-friendly spaces, quiet areas, predictable routines, and clear visual supports can help people with either condition.
• Skills-focused interventions: Social skills training, executive function coaching, and organisational supports can reduce everyday barriers.
• Psychological therapies: Cognitive behavioural approaches can help manage anxiety, low mood, and some behavioural challenges.
• Medication: For ADHD, stimulant and non-stimulant medications are evidence-based options to reduce inattention and impulsivity for many people. Medication does not treat autism itself but may address co-occurring symptoms such as severe hyperactivity or anxiety in some cases.
• Education and workplace accommodations: Individual Education Plans (IEPs), exam adjustments, flexible work arrangements and assistive technology often make a practical difference.
• Family and carer support: Training, peer support and practical resources help families implement strategies consistently across settings.

When autism and ADHD overlap, supports need to be coordinated—what helps one condition may not fully address the other. For example, sensory adjustments may help autistic sensory overload, while organisational coaching and medication could reduce ADHD-related inattentiveness.

Practical next steps

• Try a screening tool if you suspect either condition: NeuroDirect’s online ADHD and autism screening tests are a quick first step to guide whether a full assessment is needed (NeuroDirect ADHD screening, NeuroDirect RAADS-R test).
• Speak to your GP or an appropriate professional to discuss results and referral options.
• Collect information from multiple settings (school reports, employer feedback, family observations) to support a thorough assessment.
• Focus on tailored supports that match the person’s unique profile—small environmental changes and practical strategies often produce quick benefits.

Summary

Autism vs ADHD is not an either/or question in every case. They share overlapping traits but have different core features: autism centres on social communication differences and restricted patterns of behaviour, while ADHD is defined by persistent inattention and/or hyperactivity-impulsivity. Many people have both conditions, and accurate diagnosis requires a careful, multi-source assessment. Support is most effective when it is personalised and addresses the whole person—sensory needs, executive functioning, emotional well-being and daily living.

Take our free autism and ADHD screening tests online.

FAQ