ADHD glossary

Plain-English definitions of the adult ADHD terms you meet on a referral, at an assessment, on a prescription or at work. Grouped by topic, written for people navigating the UK system, not for a textbook. Where a term is covered in depth on ADHD Helper, the term links straight to the guide.

Information only, not medical advice, and never a diagnosis. Diagnosis and treatment are decisions for a registered clinician.

How to use this glossary

Each term is grouped by topic. Skim the headings to find the area you need, then the bold term within. Definitions are short and assume you are looking at a letter, appointment or prescription and need a fast, accurate read. Some terms, such as time blindness and rejection sensitive dysphoria, are widely used descriptions rather than formal diagnoses, and we say so. Where a term maps to a primary UK source, such as NICE, the NHS, gov.uk or the Equality Act, a source link sits under the definition.

Diagnosis and assessment

How ADHD is recognised and diagnosed. A checklist or online test can flag whether to seek help, but only a suitably qualified clinician can diagnose ADHD after a proper assessment.

ADHD: Attention deficit hyperactivity disorder is a recognised neurodevelopmental condition that affects attention, activity levels and impulse control. A specialist diagnoses it against criteria in DSM-5 or ICD-11, and it often continues into adulthood. It is not caused by poor parenting or a lack of effort. Source: NICE guideline NG87
Neurodevelopmental condition: A condition that affects how the brain develops and works from early life, such as ADHD or autism. The traits are lifelong and show up across different situations, rather than being a temporary reaction to stress or circumstances.
Combined presentation: The ADHD presentation where a person meets the criteria for both inattentive and hyperactive-impulsive traits. It is the most commonly diagnosed presentation. Presentations can shift over a lifetime, as visible hyperactivity often settles in adults.
Predominantly inattentive presentation: The ADHD presentation dominated by attention and organisation difficulties, such as losing focus, missing detail and struggling to finish tasks, without prominent hyperactivity. Historically called ADD. It is often identified later, particularly in women and girls.
Predominantly hyperactive-impulsive presentation: The ADHD presentation dominated by restlessness, fidgeting, interrupting and acting without thinking, with fewer recorded attention problems. It is more often noticed in childhood. A specialist assesses which presentation, if any, fits.
Assessment: A structured evaluation by a suitably qualified clinician, such as a psychiatrist or specialist nurse, to decide whether someone meets the diagnostic criteria for ADHD. It usually includes a clinical interview, history and rating scales, and it is the only route to a diagnosis. Source: NICE guideline NG87
DIVA-5: The Diagnostic Interview for ADHD in adults, a structured interview a clinician uses to check current and childhood symptoms against the diagnostic criteria. It is one recognised tool among several; a positive interview supports, but does not by itself confirm, a diagnosis.
QbTest: A computer-based test that measures attention, impulsivity and movement, sometimes used to support an ADHD assessment. It is an aid to clinical judgement, not a standalone diagnosis; a clinician interprets the result alongside history and interview.
Screening tool (ASRS): A short self-report questionnaire, such as the Adult ADHD Self-Report Scale, that flags whether a full assessment may be worthwhile. A high score suggests it is worth seeking assessment; it cannot diagnose ADHD and does not replace a clinical evaluation.
Differential diagnosis: The process a clinician uses to tell ADHD apart from, or alongside, other things that can look similar, such as anxiety, depression, sleep problems or autism. It matters because the right support depends on getting the picture right. Source: NICE guideline NG87

NHS routes and access

How adults get assessed in England: the local NHS route, Right to Choose and going private. Waiting times vary a lot by area, which is why the route you pick matters.

Right to Choose: In England, a legal right that lets most adults choose which NHS-funded provider they are referred to for a first outpatient appointment, including many ADHD assessment providers. It can shorten waits, but a GP referral is still needed and the provider must have an NHS contract.
Referral: A request, usually from a GP, that sends you to a service for assessment or treatment. For an ADHD assessment on the NHS you normally need a referral, whether to a local service or, under Right to Choose, to a chosen NHS-funded provider.
GP referral letter: The letter a GP writes to refer you for an ADHD assessment. Under Right to Choose you can ask for the referral to go to a specific NHS-funded provider. A referral letter typically needs the provider name, your details and a brief clinical reason.
ICB (Integrated Care Board): The NHS body responsible for planning and funding most health services in a local area of England. ICBs decide local funding and can affect ADHD waiting times, and some have paused or restricted certain Right to Choose pathways.
Waiting list: The queue for an NHS assessment or appointment. Adult ADHD waits vary widely by area and can run to years in some places, which is why people compare the NHS local route, Right to Choose and private assessment.
Private assessment: An ADHD assessment paid for privately, outside NHS funding, usually with a much shorter wait. A diagnosis from a suitably qualified private clinician is generally valid, though arranging NHS shared care for medication afterwards can depend on your GP and local policy.
Shared care agreement: An arrangement where a specialist starts and stabilises ADHD medication, then your GP takes over routine prescribing and monitoring under an agreed plan. GPs are not obliged to enter shared care, which is one reason some people are asked to stay with the specialist.

Medication and treatment

The medicines a specialist may consider, and the terms around them. Whether medication is right for you, and which one, is always a clinical decision made with a prescriber, not something to arrange yourself.

Titration: The phase at the start of ADHD medication where the dose is adjusted gradually under clinical supervision to find the amount that helps most with the fewest side effects. It involves regular reviews of benefit, blood pressure, heart rate and wellbeing.
Stimulant medication: The most commonly prescribed type of ADHD medication, including methylphenidate and lisdexamfetamine. Stimulants are controlled drugs, started and titrated by a specialist. Whether medication is suitable is a clinical decision made with you, and it is one part of a wider support plan. Source: NHS
Non-stimulant medication: ADHD medicines that are not stimulants, such as atomoxetine and guanfacine, sometimes used when stimulants are unsuitable, not tolerated or not effective. They can take longer to show benefit. A specialist decides what, if anything, to prescribe.
Methylphenidate: A stimulant medicine (brand names include Concerta, Medikinet and Xaggitin) commonly used for ADHD, available in short and long-acting forms. It is a controlled drug prescribed and monitored under specialist guidance. Only a clinician can decide if it is right for you.
Lisdexamfetamine: A long-acting stimulant medicine (brand name Elvanse) used for ADHD, taken once a day. It is a controlled drug started and adjusted by a specialist. Any decision to prescribe, change or stop it is a clinical one.
Atomoxetine: A non-stimulant ADHD medicine (brand name Strattera) that works differently from stimulants and can take several weeks to reach full effect. It is not a controlled drug. A specialist assesses whether it is appropriate and monitors its use.
Guanfacine: A non-stimulant ADHD medicine (brand name Intuniv) that can help with attention and impulsivity, more often used in children and young people. It affects blood pressure and heart rate, so it needs monitoring. Prescribing is a specialist decision.
Controlled drug: A medicine subject to extra legal controls on how it is prescribed, stored and supplied because of its potential for misuse. Most ADHD stimulants are controlled drugs, which affects prescription rules, repeat supplies and travelling abroad with them.
Medication shortage: A period when an ADHD medicine is hard to obtain because of supply disruption. During a shortage a specialist may adjust the dose, switch product or brand, or advise on options. Do not stop or change medication yourself; speak to your prescriber or pharmacist.

How ADHD shows up

Everyday words for the way ADHD affects attention, memory, emotion and time. Some are formal clinical terms; others are widely used descriptions rather than diagnoses, and we say which is which.

Executive function: The set of mental skills used to plan, start and organise tasks, manage time, hold information in mind and control impulses. Differences in executive function are central to how ADHD affects everyday life at work, home and study.
Working memory: The ability to hold and use information in mind for a short time, such as remembering instructions while carrying them out. Working-memory differences are common in ADHD and help explain forgetfulness, losing track mid-task and difficulty following multi-step directions.
Emotional dysregulation: Difficulty managing the intensity and timing of emotions, so feelings can arrive fast and strong and take longer to settle. It is widely recognised as part of many people's experience of ADHD, though it is not one of the core formal diagnostic criteria.
Rejection sensitive dysphoria (RSD): A term used in the ADHD community for intense emotional pain triggered by real or perceived rejection or criticism. It is widely discussed but is not a formal diagnosis in DSM-5 or ICD-11. If it affects you, a clinician can still help you address it.
Hyperfocus: A state of deep, absorbed concentration on something engaging, to the point of losing track of time or surroundings. Often described in ADHD, it shows that the difficulty is regulating attention and directing it where needed, rather than a simple lack of focus.
Time blindness: An informal term for difficulty sensing how much time has passed or how long a task will take, leading to lateness, missed deadlines or underestimating effort. It is a common way people describe the time-management side of ADHD.
Masking: Consciously or unconsciously hiding ADHD traits to fit in, for example over-preparing, scripting conversations or suppressing restlessness. Masking can delay diagnosis, especially in women, and is often exhausting. It can mean someone appears to cope while struggling underneath.

Support, work and daily life

Practical support beyond medication: your rights at work, government schemes, coaching and strategies people use day to day.

Reasonable adjustments: Changes an employer or place of study must consider to remove disadvantage for a disabled person under the Equality Act 2010. For ADHD these might include flexible hours, written instructions, a quiet space or extra time. ADHD can count as a disability under the Act. Source: Equality Act 2010
Access to Work: A UK government scheme that can provide practical support and funding for people with a health condition or disability to stay in or start work, such as coaching, equipment or a support worker. It can be relevant for adults with ADHD. Source: gov.uk
ADHD coaching: Practical, goal-focused support to build routines, systems and strategies for managing time, tasks and organisation with ADHD. Coaching is not therapy or medical treatment and coaches are not regulated, so it complements, rather than replaces, clinical care.
CBT (cognitive behavioural therapy): A structured talking therapy that helps you change unhelpful thought and behaviour patterns. For ADHD it is sometimes used alongside medication to build coping strategies and address linked anxiety or low mood. Trained therapists deliver it.
Body doubling: A strategy where doing a task alongside another person, in the room or online, makes it easier to start and stay on it. It is a popular, informal ADHD productivity technique, not a medical treatment.

Common questions

What is the difference between ADHD and ADD?

ADD is an older name for what is now called the predominantly inattentive presentation of ADHD: attention and organisation difficulties without prominent hyperactivity. Since DSM-5, everything sits under the single term ADHD, described by presentation (inattentive, hyperactive-impulsive or combined). ADD is not a separate condition and is no longer a formal diagnosis.

Is a private ADHD diagnosis valid on the NHS?

A diagnosis from a suitably qualified private clinician is generally valid. The practical issue is medication: for your GP to take over prescribing you usually need a shared care agreement, and GPs are not obliged to enter one. Whether a private diagnosis leads to NHS shared care depends on your GP and local policy.

What does titration mean for ADHD medication?

Titration is the phase at the start of ADHD medication where a specialist adjusts the dose gradually to find the amount that helps most with the fewest side effects. It involves regular reviews of benefit, blood pressure, heart rate and wellbeing before a stable dose is agreed.

What is NHS Right to Choose for ADHD?

Right to Choose is a legal right in England that lets most adults choose which NHS-funded provider they are referred to for a first outpatient appointment, including many ADHD assessment providers. It can shorten waits, but you still need a GP referral and the provider must hold an NHS contract. Some local areas have restricted certain pathways.

Is ADHD a disability under UK law?

ADHD can count as a disability under the Equality Act 2010 where it has a substantial, long-term effect on everyday activities. That can entitle you to reasonable adjustments at work or in study, such as flexible hours or written instructions. Whether it applies is judged on individual impact, not the label alone.

Can an online test diagnose ADHD?

No. Online screening tools such as the ASRS can flag whether a full assessment may be worthwhile, but they cannot diagnose ADHD. A diagnosis needs a proper assessment by a suitably qualified clinician, using a clinical interview, history and rating scales. Treat a high screening score as a prompt to seek assessment.

Not sure where to start?

If you think you might have ADHD, the usual first step is understanding your options for getting assessed. Our guides walk through NHS Right to Choose, private assessment and what happens next, in plain English.

Understand NHS Right to Choose →

Adam Parker

Editor, ADHD Helper

Adam leads ADHD Helper's editorial coverage of adult ADHD, and he writes it from lived experience: Adam has ADHD himself, diagnosed as an adult, and has been through the assessment routes and the daily workarounds this site covers. He is the founder and managing director of Muswell Rose and researches the plain-English explainers on getting an ADHD assessment through NHS Right to Choose or privately, and on the products and tools people use to manage ADHD, drawing on guidance from the NHS, NICE and the Royal College of Psychiatrists. He is clear that the site is information, not medical advice, and that diagnosis is for a registered clinician.

Last reviewed: 8 July 2026