Rating scales help — but cannot make the diagnosis
NICE specifically states that ADHD should not be diagnosed solely on the basis of rating-scale or observational data. Questionnaires are useful supporting tools when they sit inside a broader assessment.
What the clinician is looking for
Developmental pattern
ADHD is neurodevelopmental, so the assessment looks for a history extending back into childhood rather than only recent concentration problems.
More than one setting
Clinically relevant symptoms should affect important areas such as work, education, home, family or social life rather than appearing in only one narrow context.
Meaningful impairment
The clinician considers how symptoms affect functioning, not only whether a symptom checklist can be endorsed.
Differential assessment
Other explanations and co-occurring conditions need to be considered as part of the diagnostic process.
Before choosing a private UK assessment
Check who will conduct the assessment, their professional registration and ADHD expertise, what diagnostic standards are used, what collateral/developmental information is required, and what follow-up is available if treatment is recommended.
Official source
NICE NG87: Attention deficit hyperactivity disorder — diagnosis and management.
More ADHDclearfocus UK resources
Start with structured self-observation
If you are deciding whether a formal assessment is worth pursuing, the ADHDclearfocus self-assessment can help you organise examples before speaking to a clinician. It does not diagnose ADHD.
Free ADHD self-assessment →Prepared by the ADHDclearfocus editorial team and clinically reviewed through Focused Care Psychology. Last reviewed 3 September 2026. Pathways and service availability can change; check current official guidance and provider information.