Assessment Process
A comprehensive, clinically led approach to adult ADHD diagnosis
Horizon Clinical Group provides comprehensive, evidence-based ADHD diagnostic assessments for adults seeking clarity, understanding and validation. Assessments are carried out virtually across the UK by an experienced Registered Mental Health Nurse, using internationally recognised assessment tools alongside detailed clinical history, professional judgement and an assessment approach informed by NICE Guideline NG87.
BEFORE YOUR ASSESSMENT
Preparation begins before your appointment
Once your assessment is booked, you will receive a series of secure pre-assessment forms to complete before your appointment.
These may include appropriate screening tools or questionnaires, alongside forms exploring your personal, developmental history and current experiences.
You will also be asked to approach a relative or another person who knew you during childhood, before the age of 12, and ask them to provide information about your early development and childhood experiences. You will be responsible for arranging this information and ensuring it is returned as part of your pre- assessment. If available, you are also welcome to provide supporting childhood documentation, such as school reports, educational records or other relevant historical information that may help provide further evidence of your development and experiences before the age of 12.
Childhood history forms an important part of an ADHD assessment because the DSM-5 diagnostic criteria require several ADHD symptoms to have been present prior to the age of 12.
Please return your completed forms at least 3 days before your assessment. These can be completed and submitted securely via WriteUpp. This allows your information to be carefully reviewed in advance, ensuring your appointment can be focused around your individual history and experiences.
Screening questionnaires and supporting information form part of the wider clinical assessment and are not used in isolation to determine a diagnosis.
YOUR CLINICAL ASSESSMENT
Experienced clinical assessment, centered around you
Your assessment is carried out by an experienced Registered Mental Health Nurse with 14 years of frontline clinical and assessment experience.
The assessment goes beyond questionnaires or a checklist of symptoms. Your clinician will explore your developmental history, current experiences, mental health, functioning and the impact of difficulties across different areas of your life.
This includes consideration of areas such as work, education, relationships, home life, organisation, attention, impulsivity, emotional regulation and day-to-day functioning.
Your childhood experiences are explored alongside your current presentation, including information provided by your nominated childhood informant.
The assessment also considers whether your experiences may be better explained by another condition, whether there are co-occurring difficulties, and how your symptoms have affected your functioning over time.
The aim is to build a comprehensive clinical picture of you as an individual, rather than simply determining whether you identify with a list of ADHD symptoms.
STRUCTURED DIAGNOSTIC INTERVIEW
A secure, 90-minute virtual clinical assessment
Your assessment takes place via a secure virtual appointment lasting approximately 90 minutes, allowing Horizon Clinical Group to provide adult ADHD assessments UK-wide.
The DIVA-5 (Diagnostic Interview for ADHD in Adults) is an internationally recognised, gold-standard structured diagnostic interview, based on the DSM-5 diagnostic criteria for ADHD.
The interview explores both childhood and adult symptoms, their impact on everyday functioning, and how difficulties may have presented across different settings.
DIVA-5 forms one part of the wider clinical assessment and is considered alongside your developmental history, pre-assessment information, childhood informant information, current presentation, functional impact and professional clinical judgement.
This structured approach allows your assessment to remain thorough, consistent and individualised, while giving you the opportunity to explain your experiences in your own words.
CLINICAL STANDARDS & SUITABILITY
Evidence-based assessment informed by NICE Guideline NG87
NICE Guideline NG87 — Attention deficit hyperactivity disorder: diagnosis and management provides an important clinical framework for our assessment approach.
NICE recommends that ADHD diagnosis is based on a full clinical and psychosocial assessment, including developmental and psychiatric history, consideration of symptoms across different settings and assessment of functional impairment. Rating scales should not be used as the sole basis for diagnosis.
Horizon Clinical Group is a strictly adult service, providing planned, non-urgent virtual diagnostic assessments for individuals who are appropriate for this type of service.
Our virtual service is not suitable for individuals currently experiencing an acute psychiatric crisis, active psychosis or severe substance addiction.
If you are experiencing immediate distress or require urgent mental health support, please contact your GP or NHS 111. If you are in immediate danger, contact 999 or attend your nearest Emergency Department.
YOUR DIAGNOSTIC REPORT
A comprehensive report providing clarity you can take forward
Following your assessment, you will receive a comprehensive written diagnostic report documenting the information considered, clinical formulation and diagnostic outcome.
Where ADHD is diagnosed, your report provides professional supporting documentation that can be used when discussing your needs with your employer, university, occupational health service or other organisation.
It may support conversations around reasonable adjustments, workplace support or educational accommodations, and can provide supporting evidence for relevant applications or benefits where appropriate.
Your report is designed to give you more than a diagnostic label. It provides a clear account of your experiences, the clinical evidence considered and the outcome of your assessment — giving you professional documentation that you can take forward.
Horizon Clinical Group focuses exclusively on assessment, diagnosis and understanding. We do not provide medication prescribing or titration.