How we diagnose ADHD: our clinical approach
We diagnose ADHD the way the NICE guideline says it should be done: a specialist psychiatrist, a full clinical assessment, evidence from more than one source, and careful checks for anything else that could explain your difficulties. A questionnaire or a short call is never enough on its own.
In short
- Only a consultant psychiatrist makes a diagnosis at ADHD Health, following the NICE guideline on ADHD (NG87).
- Symptoms must meet DSM-5 or ICD-11 criteria: they started in childhood, show up in 2 or more settings and cause at least moderate difficulties.
- We use a structured interview, your history and the views of someone who knows you well, or your child’s school.
- Rating scales support the assessment but never decide it, and we check for other conditions every time.
- We don’t promise an outcome. The fee is the same whatever we find.
Who can diagnose ADHD?
NICE says: “A diagnosis of ADHD should only be made by a specialist psychiatrist, paediatrician or other appropriately qualified healthcare professional with training and expertise in the diagnosis of ADHD.”
At ADHD Health, adults are assessed by Dr Helen Carter, Consultant Psychiatrist. Children and teenagers are assessed by Dr Arjun Mehta, Consultant Child and Adolescent Psychiatrist. Our nurse prescriber, our CBT therapist and our patient care team don’t make diagnoses. Meet them on our team page.
What has to be true for an ADHD diagnosis?
NICE says symptoms must meet the criteria in one of the two international classifications, DSM-5 or ICD-11. They must also cause at least moderate psychological, social, educational or work difficulties, and be pervasive, occurring in 2 or more important settings, such as home, school, work or social life.
| Criterion | DSM-5 | ICD-11 |
|---|---|---|
| Symptoms | At least 6 symptoms of inattention and/or 6 of hyperactivity and impulsivity up to age 16. At least 5 from age 17 | A persistent pattern of inattention and/or hyperactivity and impulsivity beyond what’s expected for age and development. No fixed number |
| How long | At least 6 months | At least 6 months |
| When it started | Several symptoms before age 12 | Significant symptoms before age 12, though some people only come to attention later |
| Where | Several symptoms in 2 or more settings | Across multiple situations or settings |
| Impact | Clear evidence that symptoms interfere with, or reduce, everyday functioning | A direct negative effect on study, work or social life |
| Other explanations | Not better explained by another condition | Not better explained by another condition, or by a substance or medicine |
If ADHD is diagnosed, your report also says which presentation fits best: mainly inattentive, mainly hyperactive and impulsive, or combined.
How we gather the evidence
NICE asks for a full clinical and psychosocial assessment, a full developmental and psychiatric history, observer reports and an assessment of your mental state. In practice, that means:
- Questionnaires before the appointment These cover current difficulties, childhood and health. They help us plan the interview and measure how often symptoms happen, so the 60-minute appointment can focus on your real-life examples.
- A structured clinical interview For adults, a structured clinical interview, which can be guided by a tool such as DIVA-5. It covers the 18 DSM-5 symptoms, in childhood and now, starting from your questionnaire answers, and asks for real-life examples and their effect on work, study, relationships, family life and free time.
- Your history Development, education and work, mental and physical health, family history, sleep, medicines, alcohol and drugs, and how you are feeling now.
- Someone else’s view For adults, a questionnaire from someone who knew you as a child, ideally a parent or older sibling, or old school reports. For children, questionnaires and reports from school, plus any earlier assessments.
Rating scales support the decision. They never make it.
NICE says a diagnosis should not be made solely on the basis of rating scales or observation. A high score shows that someone reports many symptoms, not why. Your psychiatrist looks at the whole picture and the real examples behind the scores.
Other explanations, and conditions that come with ADHD
Several conditions can look like ADHD, and some often come alongside it. We check for them in every assessment, because they change what will help.
If something else explains your difficulties better, we’ll say so, and ADHD won’t be diagnosed. If you have ADHD and another condition, we’ll explain how they affect each other and what to do next, including whether the other condition needs treatment or a separate assessment first.
- Anxiety and depression
- Autism
- Sleep problems
- Trauma and stressful life events
- Alcohol and drug use
- Mood disorders such as bipolar disorder
- Physical health problems, and medicines that affect concentration or energy
- In children, learning difficulties, language difficulties and tics
Assessing children: home, school and development
Because NICE requires difficulties in 2 or more settings, school information is part of every child assessment. Dr Mehta brings together:
- A 60-minute video session with your child and you, covering early development, health, family life, school and friendships
- Time in the same session with your child, to hear their views and see how they are. Teenagers can talk on their own for part of it
- Questionnaires from parents and from a teacher or SENCO, school reports and any earlier assessments, such as from an educational psychologist
- A judgement about whether behaviour goes beyond what’s expected for your child’s age and stage of development
Dr Mehta shares what he has found at the end of the session where he can, and your written report follows within 48 hours. Read more about our assessment for children and teenagers.
What we don’t do
- We don’t diagnose from a questionnaire, our self-check or a short call. Questions you ask our non-clinical patient care team are never part of the assessment.
- We don’t promise an outcome. You pay for a careful assessment, and the fee is the same whatever we find.
- We don’t diagnose without evidence about childhood. If it’s missing, we’ll tell you what’s needed.
- We don’t rush to a decision. If we need more information, we’ll explain what and why.
- A diagnosis doesn’t mean you’ll be offered medication. Treatment is a separate decision you make with your clinician.
Outcomes and second opinions
There are three possible outcomes: ADHD is diagnosed, ADHD isn’t diagnosed, or more information is needed before we can decide safely. Whatever the outcome, we explain the reasons and what might help next.
If you disagree with the outcome, tell us. Your psychiatrist will go through the evidence with you. You can also ask for a second opinion, through your GP or from another specialist. If you’re unhappy with how we assessed you, see our complaints policy.
Your report and your GP
Your report is written so that you, your GP and other professionals can see how the outcome was reached. It covers:
- The outcome and, if ADHD is diagnosed, the presentation
- Examples showing how each criterion was or wasn’t met
- Other conditions considered, and why
- Any limits, such as little information about childhood
- Recommendations for support, adjustments and treatment
With your consent, we send it to your GP. We send it within 48 hours of an adult assessment, and within 48 hours of a child or young person’s assessment. GPs can read our information for GPs.
Quality checks
Complex or uncertain assessments are discussed with a second senior clinician before the outcome is final. We review our assessment process against the NICE guideline, and update this page when the guidance changes.
Across the four UK nations
NICE guidance is written for England. Wales follows it, and Northern Ireland’s Department of Health endorses it. Scotland isn’t bound by NICE and has its own national guidance. The diagnostic criteria, DSM-5 and ICD-11, are the same everywhere, and we assess people living anywhere in the UK in the same way.
Sources
- NICE. Attention deficit hyperactivity disorder: diagnosis and management (NG87). Last updated 2025.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5). 2013; text revision 2022.
- World Health Organization. ICD-11: 6A05 Attention deficit hyperactivity disorder. 2024 release.
- The Open University. Understanding ADHD: diagnosing ADHD with DSM-5. Accessed October 2026.
- DIVA Foundation. DIVA-5: Diagnostic Interview for ADHD in adults. 2019.
- Leaver L, van Rensburg K, Adamou M and others. Assessments for adult ADHD: what makes them good enough? British Journal of General Practice, October 2023.
- NHS. ADHD: diagnosis. Page reviewed 19 March 2025.
Questions about how we assess?
Ask our patient care team a question about the process, or go straight to booking an assessment.
Or call us on 0306 999 0123, 10am to 8pm, 7 days a week.