How Long Does an ADHD Assessment Take?

When you’re busy with work or childcare, setting aside time to book a GP appointment for an ADHD assessment can be a logistical nightmare. 

With NHS waitlists getting longer and longer, it can feel like you’ll never get the answers you’re looking for. So, if you’ve ever wondered how long an ADHD assessment really takes, we’re here to help. 

In this guide, we’ll look at how long an ADHD assessment takes, including times for children, adults, and NHS, Right to Choose, and private pathways. 

How Long Does an ADHD Assessment Take? The Short Answer

In short, an ADHD assessment can take between 60 and 90 minutes for the initial assessment and up to several years when waiting for an NHS appointment after referral.

When you go private, there’s no waiting for a referral; you simply book an appointment slot that works for you. As such, the wait time will go down to only a few weeks (provider dependent), but the assessment itself will still take at least 60 minutes to complete. 

For children, you’ll be looking at around 90 minutes to 3 hours for the assessment, as there are more steps in the assessment process for a child. 

Pre-assessment questionnaires typically take around one to three hours to fill in, while you may be waiting up to two weeks for your feedback report.

The ADHD Assessment Process: Step by Step

The best way to get an accurate picture of how long an ADHD assessment actually takes is to break it all down. 

Each stage takes a different amount of time, with most ADHD assessments including the following four steps: 

• Referral or booking
• Pre-assessment questionnaires 
• Clinical interview
• Feedback and written report

We’ll detail what happens in an ADHD assessment and how long it typically takes to complete each stage. However, keep in mind that specific times may differ in more complex  cases.  

Referral or Booking

Step one is to arrange an NHS referral or private booking for an ADHD assessment. Each pathway has its own typical wait times. 

For a referral to an NHS assessment, you’ll need to speak to your GP first. It might only take a few minutes to discuss an assessment with your GP, but once referred, it can take around five years to receive an appointment due to NHS waiting lists. However, exact wait times will vary by region, with some areas seeing a wait of over six years. 

If you’re going private, it’s simply a matter of finding the right provider and booking your appointment through them — no referral needed. This can be as fast as four weeks. 

You can also look at the Right to Choose pathway, which allows you to book your assessment with an NHS-contracted private provider, at no cost to you. Typical wait times start from four weeks, according to ADHD UK. This pathway is only available in England. 

Expected time: four weeks to six years or more (pathway and region dependent)

Pre-Assessment Questionnaires 

Once you’ve received your appointment time, you’ll need to fill in a pre-assessment questionnaire to help your clinician get to know you better. 

They’ll ask questions about your medical history, family background, past medications, and developmental history. You’ll also be sent a self-report form which uses a rating scale to assess potential traits and their impact on you. 

You’ll need to give contact details for a parent, partner or close family member who is happy to fill in an observer feedback form, too. 

Expected time: one to three hours

Clinical Interview

Next, you’ll be invited to a clinical interview with a specialist, where they’ll evaluate you against diagnostic criteria. Generally, they’ll use the DSM-5 criteria throughout this stage. 

There’s plenty to cover during the interview: core symptoms, childhood history, day-to-day impacts. As such, you can expect this part to take around 60 to 90 minutes. 

Your clinician may also review your medical history after the interview, so your overall assessment time can run a little longer. Plus, in some cases, they may need to check for other conditions with overlapping symptoms, such as anxiety, depression or sleep disorders. 

Expected time: 60 to 90 minutes

Feedback and Written Report

Once you’ve completed your ADHD assessment, it’s simply a case of waiting for the clinician to review their findings and put together a written report. 

In most cases, they’ll be able to give you initial feedback on the same day as your appointment. However, for a more in-depth report, it can take up to two weeks depending on the pathway you chose. 

For the NHS, it typically takes up to two weeks to receive the report in full. Private providers have their own schedules, but it can be as quick as five days. 

Expected time: up to two weeks (pathway dependent)

How Long Does an ADHD Assessment Take: Adult vs Child 

Child assessments usually take a little longer than adult ones, as clinicians need input from more people.

Knowing what to expect from the process can make it feel a bit less daunting, especially for children. So, let’s take a look at how long an adult ADHD assessment takes and how long a child ADHD assessment takes. 

How Long Does an Adult ADHD Assessment Take?

An adult ADHD assessment takes around 90 minutes to conclude, excluding referral or booking times. 

During your assessment, the clinician speaks with you about work, relationships, mental health history, and how you feel ADHD symptoms impact you on a day-to-day basis. In more complex cases with co-occurring conditions, this can take towards the longer end of the expected time. 

How Long Does an ADHD Assessment Take for a Child?

A child ADHD assessment can take between one and a half and two hours, as the clinician will need to speak to several people involved in the child’s care or education.

Clinicians will also gather information from the child’s school, usually through a questionnaire or report. Their parent or carer will need to be interviewed about how the child acts at home and their developmental history.

Children need to be interviewed, too, but questions will be specifically adapted to suit the child’s age. Typically, they’ll be asked about their feelings, day-to-day experiences, and general likes or dislikes. 

ADHD Assessment Wait Times: NHS vs Right to Choose vs Private

It’s often the wait time for the actual ADHD assessment that can be the longest, especially with an NHS appointment. To help you choose the right pathway for you, let’s look at the average wait time for each common pathway. 

NHS 

Due to heavy demand, the NHS is currently experiencing lengthy waiting times for ADHD assessments. In some cases, you may be waiting more than five years for an appointment. 

However, the region you live in plays a big part in how long you can expect to wait. For example, the average wait time in Liverpool is 340 weeks (6.5 years), as of August 2026. In contrast, the average wait is over three years in South East London. Services in South West London have an even shorter wait time of around 93 weeks, which is just under two years.

Right to Choose

Wait times through the Right to Choose pathway depend on the specific provider you go through, but they can range from 4 to 12 weeks. 

Before you decide on a clinician to use, make sure to check their wait times match the timeline you had in mind for assessment. Keep in mind that while Right to Choose is free, you’ll still need to be referred by your GP for this pathway. 

Private

Generally, one of the fastest ways to get an ADHD assessment is to go private, with wait times starting from as little as four weeks with some providers. 

While going private is faster, you do need to fund the cost of the assessment yourself. Some providers will offer payment plans, but you can also look into using health insurance to cover the costs in part or in full. 

Not every health insurance provider will include ADHD assessments as part of their coverage, so always make sure you confirm with your provider before booking. 

How to Prepare for Your ADHD Assessment

Being prepared for your ADHD assessment can help things run more smoothly, as all the required information is ready when you reach the clinical interview. Depending on whether you’re getting an assessment for yourself or a child in your care, the steps will be different. 

To prepare yourself for an adult ADHD assessment, follow these steps:

• Note down your symptoms
• Document how symptoms impact you
• Ask a partner or close family member to fill in an observer questionnaire 
• Fill in your pre-assessment questionnaire 

To help a child prepare for their ADHD assessment, take the following steps: 

• Make a note of their symptoms, including where they happen (e.g. home or school) 
• Keep a diary of their behaviour
• Collect any school reports 
• Let the school know they’re getting an ADHD assessment

Reach Out to Neuroaffinity for a Fast ADHD Assessment

Here at Neuroaffinity, we provide fast, compassionate ADHD assessments for both children and adults. 

We have a wait time as short as four weeks, helping you get the answers you need as fast as possible. With no GP referral needed, all you have to do is reach out to us, let us know you’re looking for an ADHD assessment, and we’ll get you started. 

Get in touch with us today to discuss an ADHD assessment for you or your child. Call us on 07768 565162 or send an email to enquiries@neuroaffinity.co.uk.