How ADHD Is Diagnosed: What to Expect in an Assessment
For many people, deciding to seek an ADHD assessment is both a relief and a source of anxiety. Relief — because it may finally explain years of struggles with attention, focus, or organisation. Anxiety — because the assessment process is often surrounded by myths, uncertainty, and worries about stigma.
This article explains how ADHD is diagnosed, what an ADHD assessment involves, and what you can expect whether you’re seeking a diagnosis for yourself or your child.
Who Can Diagnose ADHD?
In the UK and many other countries, an ADHD diagnosis must be made by a qualified healthcare professional, usually:
A psychiatrist
A suitable trained registered psychologist
A paediatrician (for children)
GPs can provide referrals but cannot usually make a full ADHD diagnosis themselves. Private ADHD assessments are also available, often providing shorter waiting times.
The Steps in an ADHD Assessment
An ADHD assessment isn’t just a “quick test.” It’s a comprehensive process designed to rule out other conditions and ensure an accurate diagnosis. Here are the key stages:
1. Initial Referral or Self-Referral
You may be referred by your GP, a teacher, or you can sometimes self-refer to private services.
The professional will check whether ADHD is the likely concern or if another condition needs to be assessed first.
2. Clinical Interview
This is the core of the ADHD assessment.
You’ll be asked about:
Current symptoms (focus, impulsivity, organisation, hyperactivity)
History of symptoms (childhood behaviours are important — ADHD is a developmental condition that starts early in life)
Family history of ADHD, learning difficulties, or mental health conditions
Impact on daily life (work, school, relationships, home)
For children, parents and sometimes teachers are asked for input, since symptoms must be seen in two or more settings (e.g., home and school).
3. Questionnaires and Rating Scales
Standardised tools such as the Conners’ Rating Scale, Vanderbilt Assessment Scale, or ASRS (Adult ADHD Self-Report Scale) may be used.
These questionnaires help measure the frequency and severity of ADHD symptoms.
They also screen for co-occurring conditions such as anxiety, depression, or autism.
4. Observation and Behavioural Assessment
In children, the assessor may observe behaviour in a structured setting or use school reports.
Adults may be asked to provide examples of challenges at work, home, or university.
5. Rule Out Other Conditions
Conditions such as anxiety disorders, depression, sleep problems, or learning difficulties can sometimes mimic or worsen ADHD symptoms.
A thorough assessment ensures these are considered, so the diagnosis is accurate.
6. Feedback and Diagnosis
Once the assessment is complete, the clinician will review the evidence against the DSM-5 criteria (US) or ICD-10/ICD-11 criteria (UK/Europe).
You’ll receive:
A clear explanation of whether the criteria for ADHD are met
Discussion of possible co-occurring conditions
Recommendations for treatment or next steps
What ADHD Diagnosis Looks Like in Children
Parents, teachers, and sometimes other caregivers provide input.
Symptoms must have been present before age 12.
Evidence is needed that difficulties occur in at least two different environments (e.g., both home and school).
Emotional, academic, and behavioural functioning are considered.
What ADHD Diagnosis Looks Like in Adults
Adults often present differently: hyperactivity may be less visible, while organisation, time management, procrastination, and emotional regulation issues are more prominent.
Adults may be asked to reflect on childhood experiences to confirm that symptoms started early.
Work history, relationships, and daily responsibilities are explored in detail.
How Long Does an ADHD Assessment Take?
Children: Typically 2–3 hours across multiple sessions.
Adults: Around 90 minutes to 3 hours, depending on complexity.
Reports are usually provided afterward, summarising findings and recommendations.
What Happens After Diagnosis?
If ADHD is confirmed, the clinician will discuss treatment and support options, which may include:
Medication (such as stimulants or non-stimulants)
Therapy (CBT, coaching, skills training)
Lifestyle strategies (routines, exercise, sleep hygiene)
School or workplace accommodations
If ADHD is not diagnosed, you should still receive recommendations for next steps — whether that’s managing anxiety, exploring autism, or other support.
Myths About ADHD Diagnosis
Myth 1: “It’s just a quick online test.”
✅ Reality: Self-check tools can suggest ADHD but are not diagnostic. A full clinical assessment is essential.
Myth 2: “Only children can be diagnosed.”
✅ Reality: ADHD often persists into adulthood, and adult diagnosis is increasingly common.
Myth 3: “It’s only diagnosed if you’re failing at school or work.”
✅ Reality: Many people with ADHD are high-achieving but still struggle behind the scenes.
Why Getting an ADHD Diagnosis Matters
A proper diagnosis can:
Provide validation (“I’m not lazy — my brain works differently”)
Open the door to effective treatment and support
Help schools and workplaces provide reasonable accommodations
Improve relationships and self-esteem by reducing misunderstandings
Conclusion
An ADHD assessment is a thorough process that looks at your history, current challenges, and how symptoms affect daily life. While it can feel daunting, knowing what to expect can make the process less intimidating.
Whether for yourself or your child, an accurate ADHD diagnosis is the first step toward understanding, support, and effective treatment.
Gentle Call to Action (for your practice site)
If you’re considering an ADHD assessment, you don’t have to go through the process alone. As a psychologist, I provide clear, supportive ADHD evaluations for both children and adults.
👉 Contact us today to learn more about arranging an ADHD assessment.