Autism Diagnostic Assessment

What is Autism?

Autism is a lifelong neurodevelopmental difference which impacts how people view, communicate and interact with the world.

It is important to understand that individuals experience autism differently. Some may attempt to “mask” their difficulties around certain people or settings in order to fit in.

THE PROCESS

Why pursue an autism assessment?

Receiving an autism diagnosis can offer meaningful insight, greater self-understanding, and access to the right support.

  • Gain clarity about your thoughts, behaviours, and social experiences, helping you make sense of how you relate to the world and process information.
  • Develop a stronger sense of identity, leading to improved self-acceptance, confidence, and emotional wellbeing.
  • Recognise your strengths, as well as areas where specific support, strategies, or adjustments could be beneficial.
  • Help others understand and support you better, including colleagues, educators, family members, and healthcare providers.
  • Access appropriate services, adjustments, and legal protections, such as workplace accommodations or support in education and daily life.

At Harley Street ADHD, we offer in-depth autism assessments led by experienced clinicians. Whether you’re exploring autism for the first time or seeking confirmation of long-standing experiences, we provide a respectful, thoughtful, and clinically robust approach to help you move forward with confidence.

Assessment information

Our autism assessments follow UK best practice guidelines and are designed with the latest clinical research in mind. Each assessment meets or exceeds the standards set by the National Institute for Health and Care Excellence (NICE).

1
Pre-screening

Prior to your assessment, we will ask you to complete some questionnaires detailing possible symptoms of autism you may have experienced both in childhood and adulthood. Where possible, we will also ask one of your parents, or someone else who has known you well in childhood, to provide information about any difficulties that they remember you experiencing when younger.

2

ADI-R Assessment (Autism Diagnostic Interview-revised)

This in-depth interview lasts 2-3 hours and is conducted by an ADI-R-trained clinician with an informant who has known you since early childhood. It will include questions about the your behaviour, language and communication, social interactions, and special interests, particularly in childhood to build a full picture of your development from an early age.

3
ADOS-2 informed assessment

You will then meet with another clinician to conduct the ADOS-2 informed assessment (Autism Diagnostic Observation Schedule). This will take around 45-60 minute and involves completing a variety of different semi-structured tasks to explore further any difficulties that you may have with social communication, relationships and day to day activities.

4
Multi-disciplinary team (MDT) discussion

Once these assessments are complete, the results will be discussed in a MDT (Multi-Disciplinary Team) meeting. This will include the two clinicians who assessed you, as well as other team members, and a decision will be made about a diagnosis of autism.

5
Feedback

The outcome of the MDT will then be discussed with you in a 30-minute feedback meeting. If a diagnosis of autism is made, the reasons for this will be fully explained to you, and you will also be provided with a variety of useful post-diagnostic resources.

6
Report

We understand the need for a prompt reporting of your assessment. We aim to complete your report within 4 weeks of your final appointment. If you require proof of diagnosis more urgently, we can provide this within 1 week.