Understanding Autism & ADHD Assessments for Children in the UK

What happens, what matters, and what to do while you wait

At Insight we support both young people and adults through autism and ADHD assessment.

This particular article focuses on children and young people under 18, as this is often when families are first navigating questions about neurodivergence, school support and diagnosis. If you’re an adult considering your own assessment journey, we’re here for that too – and we’ll be sharing more specifically about adult autism and ADHD assessments in a future post.

For now, this guide is here to help parents and carers understand what happens in an autism or ADHD assessment in the UK, to gently challenge some common myths, and to offer supportive ideas for what you can do while you’re waiting.

Why consider an autism or ADHD assessment for your child?

Choosing to access an assessment isn’t about seeking to “label” a person. It’s about understanding how they experience the world, how their brain works, and what kinds of support and adjustments might help them thrive.

Many families tell us that the decision to seek an assessment comes from wanting to understand a young person better – particularly when school, friendships, or everyday routines are starting to feel harder than expected.

A diagnosis can:

• Offer clarity and reassurance

• Help schools understand a young person's needs and strengths

• Support access to appropriate adjustments or additional help

• Give young people a language for their own differences, identity and experiences

  
  

It’s also important to say that assessment is always a choice. Some families decide they want support without a diagnosis. Others feel that formal understanding will help their child and family move forward. Both paths are valid.

What does an autism or ADHD assessment involve for young people in the UK?

A good assessment is collaborative, respectful and paced around the individual's needs. It is not about testing someone or trying to make them fit a particular mould. Instead, it builds a clear picture of their strengths, differences and support needs.

Although assessment pathways vary slightly across services, most autism and ADHD assessments for young people include the following stages.

1. Gathering background information

This often includes:

• Parent and carer questionnaires

• Feedback from educational providers (schools / colleges)

• Developmental history and early milestones

This stage helps clinicians understand how someone experiences different environments and demands, not just what is seen in clinic.

2. Clinical conversations

A clinician will talk with parents and, where appropriate, the child or young person themselves.

These conversations explore areas such as:

• Communication and social interaction

• Attention, activity levels and regulation

• Sensory preferences and sensitivities

• Emotional wellbeing and daily functioning
  

This should feel like a space where families are heard and understood, not judged.

3. Standardised assessment tools

Clinicians use structured, recognised tools to support accurate and meaningful diagnostic decisions.

For autism, this may include:

• ADOS-2: an activity-based, child-led assessment

• ADI-R: an in-depth developmental interview with parents / carers

For ADHD, this often includes:

• Behaviour and attention rating scales

• Structured interviews with parents and schools

• Observational tools

These tools are ways of understanding patterns across contexts – there is no “pass” or “fail” and we never make or withhold a diagnosis based on one source of information

4. Clinical formulation

All information is considered together to understand:

• How a person's neurodevelopmental differences show up in daily life

• What supports and adjustments are most likely to help

5. Feedback and written report

Families receive:

• A clear explanation of the outcome

• A written diagnostic report

• Recommendations for support at home and school

At Insight, feedback is not simply a report sent by email. We meet with families in a dedicated feedback appointment to talk through the findings together and develop bespoke, practical recommendations that make sense for that young person and their family.

Many families tell us that this conversation, and the clarity it brings, is one of the most supportive parts of the assessment process.

Common myths about autism and ADHD assessments

There is a lot of misinformation online, so if you’ve been feeling unsure, you’re not alone. Here are some of the things we hear most frequently:

“A diagnosis will label my child.” A diagnosis helps explain a person's experiences and can support others to understand how to help. Families can choose who they share this information with and how. The young people we see often talk to us about a feeling of "being different". Having a word to describe their differences gives them a language to talk about it.

“A private autism or ADHD diagnosis won’t be recognised by schools or services.”

This is a common worry, but it isn’t true. A comprehensive assessment completed by appropriately qualified clinicians, using recognised and validated tools, should be accepted by schools, local authorities and other services. If this is something you’re unsure about, we’re always happy to talk it through.

“Autism assessments are stressful for children.”

A neuroaffirmative assessment adapts to the needs of the person and their family. Understandably, young people and carers can feel apprehensive, which is why good services take time to explain the process and answer questions.

NHS vs private autism and ADHD assessments in the UK

Families are often encouraged to think about NHS and private assessments as if one is inherently better than the other. In reality, the picture is much more nuanced.

There are many excellent NHS autism and ADHD assessment services, delivered by skilled and thoughtful clinicians. There are also high-quality private assessments that are thorough, neuroaffirmative and supportive. At the same time, less helpful experiences can occur in both systems – often this isn't due to clinicians not caring, but because they are working under significant time pressures or constraints.

NHS assessments are free at the point of access, but waiting lists can be very long. Service pressures can limit the time available for assessment, feedback and follow-up. Private assessments often offer faster access and greater flexibility, and may allow more time for information gathering and discussion. However, private services vary widely. Not all offer the same depth of assessment, personalised recommendations, or ongoing support.

Some NHS services provide excellent follow-up after diagnosis. Some private providers do too. Others, in both settings, may offer assessment only.

What matters most is not whether an assessment is NHS or private, but how it is carried out, who delivers it, and what support is available afterwards.

Questions to ask when choosing an autism or ADHD assessment service

Because quality and approach matter more than setting, asking questions is important whether you are accessing NHS or private assessment.

Families often tell us they want reassurance that their child will be understood, not rushed or pathologised.

You might consider asking:

• Who will carry out the assessment and what is their experience?

• What assessment tools are used, and why?

• How much time is allocated for assessment and feedback?

• How are recommendations developed?

• What support is available after diagnosis?

  
  

These questions can help you decide whether a service feels aligned with your child’s needs and your family’s values.

What to do while waiting for an NHS autism or ADHD assessment

Waiting can feel frustrating and uncertain. You might feel that you already understand your child’s needs but lack the language or recognition to access support.

Some helpful things to focus on include:

• Keeping a simple record of your child’s experiences and needs

• Talking to them about what they feel helps or hinders

• Talking with school about reasonable adjustments

• Supporting transitions and routines at home

• Exploring sensory needs and emotional regulation

• Noticing and celebrating strengths

  
  

Even without a diagnosis, understanding and responding to a a young person's needs can make a meaningful difference.

How we approach autism and ADHD assessment at Insight

At Insight, our assessments are grounded in a neuroaffirmative, strengths-based and compassionate approach.

We work closely with families to understand each individual's unique profile, provide clear and thoughtful feedback, and support what comes next – whether that is school support, therapeutic input, or ongoing guidance.

We are a small service, and many families come to us through word of mouth. This allows us to take time to get to know the families we work with and to remain flexible and responsive as children grow and circumstances change. Many families return to us for further advice and support beyond the assessment itself.

If you’re thinking about assessment, or simply want to talk things through, we’re here.