ADHD in adults: symptoms, diagnosis and treatment

Key points

• ADHD affects attention, activity levels and impulse control. It begins in childhood and continues into adult life [1][2].
• Three presentations are recognised: predominantly inattentive, predominantly hyperactive-impulsive, and combined [1][2].
• Under NICE guidance, which applies in England, Wales and Northern Ireland, only a specialist psychiatrist, paediatrician or other appropriately qualified trained professional can diagnose ADHD; a GP refers instead [1]. Scotland follows SIGN 112.
• NHS England Digital estimated 2,492,000 people in England have ADHD in May 2026, with up to 803,658 open referrals in March 2026 that may be for assessment [4].
• NICE recommends medication for adults whose symptoms still impair daily life after changes to their environment, with non-drug support instead or alongside [1].

What ADHD in adults is

ADHD, attention deficit hyperactivity disorder, is a neurodevelopmental condition that affects attention, activity levels and impulse control. In adults it appears as trouble holding attention, disorganisation, restlessness and acting without thinking. ADHD does not begin in adulthood: symptoms must have started in childhood and continued since [1][2].

In the 2023/24 Adult Psychiatric Morbidity Survey, 1.8% of adults in England said a professional had diagnosed them with ADHD, and 13.9% scored above the threshold on a screening questionnaire, which flags possible ADHD only [5].

If you need help now. Samaritans: call 116 123, free, 24/7. Shout: text 85258. NHS 111, then choose the mental health option. Call 999 if anyone is in immediate danger.

Symptoms

Adult ADHD symptoms fall into two groups, and most adults have some of both [2].

Inattention:

• losing focus on tasks that are not urgent or interesting
• losing track of belongings, appointments and deadlines
• difficulty starting tasks, or finishing them

Hyperactivity and impulsivity:

• restlessness, fidgeting, difficulty sitting still
• talking a lot, interrupting, or answering before a question ends
• deciding quickly without weighing up consequences

Presentation differs from childhood. Visible overactivity often settles with age and becomes internal restlessness or difficulty switching off [2]. Inattention persists, and shows more in adult life, which demands more self-organisation.

ADHD is under-recognised in girls and women. NICE states that they are less likely to be referred, more likely to have undiagnosed ADHD, and more likely to be given an incorrect diagnosis of another condition [1]. Inattentive symptoms are more common in women and harder to recognise than hyperactive ones [2].

ADHD is commonly confused with anxiety, depression, autism and sleep problems, and often occurs alongside them [1][9].

Types

ADHD has recognised presentations rather than separate illnesses. The manuals used in the UK, ICD-11 and DSM-5, describe three [1].

• Predominantly inattentive. Attention, organisation and memory difficulties dominate, with little outward overactivity.
• Predominantly hyperactive-impulsive. Restlessness, talkativeness and impulsive action dominate. Overactivity lessens with age, so this fits fewer adults than children [2].
• Combined. Features of both groups. Most adults have symptoms from both [2].

Presentation is not fixed: NICE advises considering ADHD at all ages [1].

Causes and risk factors

There is no single cause. ADHD runs strongly in families. A review of adult ADHD genetics reports heritability of childhood ADHD estimated at around 70 to 80% in family and twin studies, although estimates based only on adults’ self-ratings are lower, roughly 30 to 41% [10]. No single gene causes it [10].

NICE lists groups with higher rates than the general population: people born preterm, people with epilepsy or acquired brain injury, people with autism or a learning disability, and people with a history of substance misuse [1]. These are associations, not proven causes.

Parenting, sugar and screen use are often blamed, and the evidence does not support them. NICE advises against removing artificial colouring and additives as a general treatment for ADHD in children and young people [1].

How it is diagnosed

ADHD should only be diagnosed by a specialist psychiatrist, paediatrician or other appropriately qualified healthcare professional with training and expertise in diagnosing ADHD [1]. A GP cannot diagnose it and refers on instead [1][2]. NICE says adults without a childhood diagnosis should be referred where symptoms began in childhood, have persisted and are not explained by another diagnosis [1].

Assessment involves a full clinical and psychosocial assessment of symptoms across the settings of daily life, a full developmental and psychiatric history, observer reports and assessment of mental state [1]. NICE states that a diagnosis should not be made on rating scale or observational data alone [1]. Symptoms must meet ICD-11 or DSM-5 criteria, happen often in two or more settings and cause at least moderate impairment [1].

No national waiting time for adult ADHD assessment is published. NHS England Digital counted up to 803,658 open referrals in England in March 2026 that may be for an ADHD assessment [4]. That is a count of referrals, not a measured wait. The independent ADHD Taskforce reported in November 2025 that demand exceeds capacity [6].

Right to Choose is a legal right in England to choose any clinically appropriate provider with a qualifying NHS Standard Contract for a first outpatient appointment after an elective GP referral [7]. It applies to mental health referrals, including ADHD assessments delivered remotely, but not to urgent or crisis care, self-referrals, or someone already in care for the same condition [7]. Available providers vary locally.

A private diagnosis by a suitably qualified professional is valid. The difficulty is prescribing. NICE expects prescribing and monitoring to move to primary care under a shared care protocol once the dose is settled [1]. The BMA describes shared care prescribing as non-core voluntary activity a GP practice can decline for any reason [8]. The ADHD Taskforce reported that many shared care arrangements for ADHD are no longer in place [6]. Where shared care is declined, medication may have to continue privately at the person’s own cost.

A diagnosis opens access to treatment and adjustments. It does not measure intelligence or effort.

Treatment

NICE places information, support and changes to a person’s environment before medication. Adults should be offered medication only if symptoms still cause significant impairment after environmental modifications have been tried [1].

Non-drug treatment should be considered for adults who choose not to take medication, cannot stick with it, or find it ineffective or intolerable, and can be added where symptoms persist [1]. NICE sets a minimum of a structured supportive psychological intervention focused on ADHD plus regular follow-up, which may include cognitive behavioural therapy, CBT [1]. Trial evidence for psychological treatment in adults is thinner than for medication.

First-line medication for adults is lisdexamfetamine or methylphenidate [1]. If neither is tolerated, or symptoms have not responded to separate six-week trials at an adequate dose, NICE recommends atomoxetine [1]. Medication should only be started by a professional trained in diagnosing and managing ADHD, after a review of mental and physical health [1]. Dose and choice of medicine rest with the prescriber.

Living with ADHD

Changes to your surroundings and routine are part of treatment. Written rather than spoken instructions, one task at a time, a quieter workspace and timers are adjustments the NHS describes [2].

NICE expects a discussion after diagnosis covering education, employment, relationships, substance misuse risk and rights to reasonable adjustments [1]. You do not have to tell an employer or university, but adjustments must be requested. You must tell the DVLA if your symptoms or your ADHD medication affect your ability to drive safely [1].

Mind notes that adults with ADHD are more likely to also experience anxiety, depression, OCD or problems with alcohol or drugs [9]. UK support organisations include ADHD UK, ADHDadultUK and ADDISS [2][9].

When to speak to a professional

Contact your GP if difficulty with attention, restlessness or impulsive decisions is causing lasting problems at work, in study or in relationships, and the pattern goes back to childhood [1][2].

Speak to your GP or specialist sooner if treatment is not helping, if you have side effects, if you are using alcohol or drugs to manage symptoms, or if low mood or anxiety is building [2].

If you are thinking about ending your life, or cannot keep yourself safe, call 999, call Samaritans free on 116 123 at any hour, or text Shout on 85258. NHS 111 has a mental health option.

Common questions

Can a GP diagnose ADHD?

No. Only a specialist psychiatrist, paediatrician or other appropriately qualified professional trained in diagnosing ADHD can make the diagnosis [1]. A GP takes a history and refers on [1][2].

How long is the NHS wait for an adult ADHD assessment?

No national waiting time is published. NHS England Digital counted up to 803,658 open referrals in England in March 2026 that may be for an ADHD assessment [4]. Waits differ widely by area.

Will the NHS accept a private ADHD diagnosis?

A private diagnosis by a suitably qualified professional is valid, but it does not oblige a GP to prescribe. NICE expects prescribing to pass to primary care under a shared care protocol [1], which the BMA calls voluntary activity a practice can decline [8].

Clinical review pending

References

1. National Institute for Health and Care Excellence. Attention deficit hyperactivity disorder: diagnosis and management. NICE guideline NG87, published 2018, last updated 2019. https://www.nice.org.uk/guidance/ng87/chapter/Recommendations
2. NHS. ADHD in adults. NHS website. https://www.nhs.uk/conditions/adhd-adults/
3. NHS. ADHD in children and young people. NHS website. https://www.nhs.uk/conditions/adhd-children-teenagers/
4. NHS England Digital. ADHD Management Information, May 2026. NHS England, 28 May 2026. https://digital.nhs.uk/data-and-information/publications/statistical/mi-adhd/may-2026
5. NHS England Digital. Adult Psychiatric Morbidity Survey: Survey of Mental Health and Wellbeing, England, 2023/24. Chapter 9: Attention deficit hyperactivity disorder. https://digital.nhs.uk/data-and-information/publications/statistical/adult-psychiatric-morbidity-survey/survey-of-mental-health-and-wellbeing-england-2023-24/attention-deficit-hyperactivity-disorder
6. NHS England. Report of the independent ADHD Taskforce: Part 2. NHS England, November 2025. https://www.england.nhs.uk/long-read/report-of-the-independent-adhd-taskforce-part-2/
7. NHS England. Patient choice guidance. NHS England, 2023. https://www.england.nhs.uk/long-read/patient-choice-guidance/
8. British Medical Association. Principles for shared care prescribing. BMA. https://www.bma.org.uk/advice-and-support/gp-practices/prescribing/prescribing-in-general-practice/principles-for-shared-care-prescribing
9. Mind. ADHD and mental health. Mind. https://www.mind.org.uk/information-support/tips-for-everyday-living/adhd-and-mental-health/
10. Franke B, Faraone SV, Asherson P, et al. The genetics of attention deficit/hyperactivity disorder in adults, a review. Molecular Psychiatry, 2012. https://www.nature.com/articles/mp2011138