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    ADHD explained: symptoms, diagnosis, treatment and the 2026 picture

    ADHD (attention-deficit/hyperactivity disorder) is a condition that starts in childhood and involves persistent inattention, hyperactivity and impulsivity that cause problems in more than one setting.[1][2] CDC estimates about 7 million US children and 15.5 million US adults have a current diagnosis.[3][4] Guidelines recommend behavioural approaches for young children and medicines, usually stimulants, for older children and adults, while shortages of those stimulants were still listed by FDA in October 2026.[5][6][7]

    Editor reviewedStrict sourcingUpdated ExplainerMental health, Health and medicine

    ADHD, short for attention-deficit/hyperactivity disorder, is diagnosed in about 7 million US children, and in the US about half of adults with a current diagnosis received it in adulthood.[3][8] This page is the first stop in a short course on ADHD in 2026: what it is, how it is diagnosed and treated, the medicine shortage, and the debate over rising diagnoses.

    This page is for general information and is not medical advice. It cannot tell you whether you or your child has ADHD. If you are concerned, talk to a doctor or other qualified clinician.

    What ADHD is

    ADHD affects attention, activity levels and impulse control. Some people mostly have trouble paying attention, some are mostly hyperactive and impulsive, and many have both.[2] The NHS gives adult examples such as being easily distracted or forgetful, struggling to organise time, losing things, feeling restless and interrupting others.[9] ADHD is diagnosed only when symptoms are persistent, began in childhood and cause real problems in more than one part of life.[1] Many young children are easily distracted and full of energy, and the NHS notes this alone does not mean ADHD.[10]

    Under the DSM criteria as summarised by the American Psychiatric Association, the diagnosis requires six frequent symptoms of inattention or of hyperactivity-impulsivity, or five from age 17.[11] Symptoms must have been noticeable for at least six months; in adolescents and adults they must have been present before age 12 and have caused difficulties in more than one setting.[1] The condition is classified into predominantly inattentive, predominantly hyperactive/impulsive and combined presentations.[2] Clinicians also look for conditions that can mimic or accompany ADHD, such as autism, Tourette’s, anxiety, depression, addiction and dyslexia.[12]

    How common it is

    CDC estimates that about 7 million US children aged 3 to 17, or 11.7%, have a current ADHD diagnosis.[3] In the 2022 national survey, about 1 in 9 children had ever been diagnosed, about 1 million more than in 2016.[13][14] Boys are diagnosed about twice as often as girls (13% versus 7%).[15] For adults, a CDC survey estimated 15.5 million (6.0%) had a current diagnosis in 2023.[4] A 2021 global meta-analysis put persistent adult ADHD, with childhood onset, at 2.58% of adults worldwide.[16]

    Whether the rise in diagnoses reflects better recognition or overdiagnosis is debated; see the analysis of rising adult diagnoses.[17][18]

    Causes

    The NHS says the cause is not always known. ADHD may be caused by genetic differences and often runs in families, and it is linked to being born prematurely, epilepsy, brain injury and autism.[19]

    Treatment in brief

    Treatment depends on age. For children under 5, NICE recommends group parent-training programmes first.[5] For school-age children, the American Academy of Pediatrics recommends FDA-approved medicine together with parent training and classroom support.[20] For adults, NICE lists lisdexamfetamine or methylphenidate as first-line medicines, and the NHS notes that not everyone needs or wants medicine.[6][21] Our ADHD medication guide covers the options.

    NICE NG87 recommends methylphenidate as first-line medicine for children aged 5 and over, and lisdexamfetamine or methylphenidate for adults, in each case only when symptoms still cause significant impairment after environmental changes.[22][6][23] The AAP’s 2019 guideline rates the evidence as particularly strong for stimulants and sufficient but weaker for atomoxetine, extended-release guanfacine and extended-release clonidine.[24] A 2018 network meta-analysis of 133 randomised trials supported methylphenidate in children and amphetamines in adults for short-term treatment, but found too little data beyond 12 weeks.[25][26]

    In 2023 CDC found that 71.5% of US adults taking stimulants for ADHD had trouble getting a prescription filled because the medicine was unavailable.[27] FDA still listed shortages of the main stimulants in October 2026.[7][28] Follow the details in the ADHD medication shortage and telehealth tracker.

    Next in this course

    Read the ADHD reference page, then ADHD in adults and the medication guide. The guide to ADHD apps and digital therapeutics covers FDA-authorised devices. Rising adult diagnoses sets out the competing views, and the tracker follows shortages, telehealth rules and enforcement. A related page explains burnout, which WHO defines as an occupational phenomenon rather than a medical condition.[29]

    Next in the crash course

    Questions readers ask

    What is ADHD?

    ADHD is a condition that begins in childhood and is divided into three presentations - predominantly inattentive, predominantly hyperactive/impulsive, and combined. For a diagnosis, symptoms must have been noticeable for at least six months and, in adolescents and adults, present before age 12 and causing difficulties in more than one setting.[2][1]

    How common is ADHD?

    CDC estimates about 7 million US children aged 3 to 17 (11.7%) and 15.5 million US adults (6.0%) have a current ADHD diagnosis. About 1 million more children had ever been diagnosed in 2022 than in 2016.[3][4][14]

    Is ADHD more common in boys?

    Boys are diagnosed more often - 13% versus 7% of girls in CDC's 2022-2023 estimates. The NHS says ADHD may be recognised less often in girls and women because inattentive symptoms can be harder to spot.[15][30]

    What causes ADHD?

    The NHS says the cause is not always known. ADHD may be caused by genetic differences and often runs in families, and it is linked to premature birth, epilepsy, brain injury and autism.[19]

    How is ADHD treated?

    NICE recommends group parent training first for children under 5, methylphenidate as the first medicine for children aged 5 and over, and lisdexamfetamine or methylphenidate for adults. The AAP recommends medication plus behavioural support for children aged 6 to 11.[5][22][6][20]

    Is there still an Adderall shortage?

    Yes. FDA's shortage list has carried immediate-release amphetamine mixed salts since October 2022, and lisdexamfetamine and extended-release methylphenidate since July 2023; all were still listed as current in data updated on 9 October 2026.[7][28][31]

    Sources

    · 31 claims from 13 publishers

    Each numbered claim is a statement we checked against the sources listed with it. Tap a number in the text to see its sources in place.

    1. [1]

      The APA says ADHD symptoms must have been noticeable over at least the past six months and, when diagnosing adolescents or adults, must have been present before age 12 and caused difficulties in more than one setting. confirmedas of 2026-10-11

      • What is ADHD? · American Psychiatric Association · Diagnosis section, which also states symptoms are "noticeable over at least the past six months" (retrieved 2026-10-11)
    2. [2]

      ADHD is divided into three presentations - predominantly inattentive, predominantly hyperactive/impulsive, and combined. confirmedas of 2026-10-11

      • What is ADHD? · American Psychiatric Association (retrieved 2026-10-11)
      • ADHD in adults · NHS (nhs.uk) · 2025-03-19 (retrieved 2026-10-11)
    3. [3]

      CDC estimates that about 7 million US children aged 3 to 17 (11.7%) have a current ADHD diagnosis. confirmedas of 2026-07-08

      • Data and Statistics on ADHD · US Centers for Disease Control and Prevention · 2026-07-08 · At a glance (page last reviewed 8 July 2026) (retrieved 2026-10-11)
    4. [4]

      CDC estimated that 15.5 million US adults (6.0%) had a current ADHD diagnosis in 2023, based on self-report. confirmedas of 2024-10-10

    5. [5]

      For children under 5 with ADHD, NICE recommends an ADHD-focused group parent-training programme as first-line treatment. confirmedas of 2019-09-13

    6. [6]

      NICE recommends lisdexamfetamine or methylphenidate as first-line medicines for adults with ADHD. confirmedas of 2019-09-13

    7. [7]

      FDA's drug shortage list has carried immediate-release amphetamine mixed salts tablets (Adderall and generics) since 12 October 2022, and the shortage was still listed as current in data updated on 9 October 2026. confirmedas of 2026-10-09

    8. [8]

      About half of US adults with a current ADHD diagnosis in 2023 were diagnosed in adulthood. confirmedas of 2024-10-10

    9. [9]

      The NHS lists adult signs of inattention such as being easily distracted or forgetful, finding it hard to organise time, and often losing things, and signs of hyperactivity and impulsivity such as restlessness, interrupting and making quick decisions without thinking. confirmedas of 2025-03-19

      • ADHD in adults · NHS (nhs.uk) · 2025-03-19 · Symptoms of ADHD (retrieved 2026-10-11)
    10. [10]

      The NHS notes that many children, particularly under 5, are easily distracted, impulsive and energetic, and that this does not mean they have ADHD. confirmedas of 2026-10-11

    11. [11]

      Under the DSM criteria as described by the American Psychiatric Association, a diagnosis of the inattentive or hyperactive type requires six frequent symptoms from the relevant list, or five for people aged 17 or older. confirmedas of 2026-10-11

      • What is ADHD? · American Psychiatric Association · Inattentive type; the hyperactive type uses the same six-or-five rule (retrieved 2026-10-11)
    12. [12]

      The NHS says GPs may consider other conditions that can cause similar symptoms, such as autism, Tourette's or anxiety, and that people with ADHD often have other conditions such as depression, anxiety, addictions or dyslexia. confirmedas of 2025-03-19

      • ADHD in adults · NHS (nhs.uk) · 2025-03-19 · Getting help with ADHD (retrieved 2026-10-11)
    13. [13]

      In the 2022 National Survey of Children's Health, about 1 in 9 US children aged 3 to 17 (11.4%, 7.1 million) had ever received an ADHD diagnosis and 10.5% (6.5 million) had current ADHD. confirmedas of 2024-05-22

    14. [14]

      About 1 million more US children had ever received an ADHD diagnosis in 2022 than in 2016. confirmedas of 2024-05-22

    15. [15]

      In CDC's 2022-2023 estimates, boys (13%) were more likely than girls (7%) to be diagnosed with ADHD. confirmedas of 2026-07-08

      • Data and Statistics on ADHD · US Centers for Disease Control and Prevention · 2026-07-08 · ADHD estimates by sex, race, and ethnicity (2022-2023) (retrieved 2026-10-11)
    16. [16]

      A 2021 global meta-analysis estimated the prevalence of persistent adult ADHD (with childhood onset) at 2.58% and of symptomatic adult ADHD at 6.76% in 2020. confirmedas of 2021-02-11

    17. [17]

      A 2021 scoping review of 334 studies found evidence of ADHD overdiagnosis and overtreatment in children and adolescents, but only five studies examined benefits and harms among additional, milder cases. confirmedas of 2021-04-01

    18. [18]

      A 2022 review argued that broader diagnostic criteria explain part of the rise in ADHD diagnoses, that increased awareness among physicians and the public, especially for women and minority groups, also plays a big role, and that detection disparities remain. confirmedas of 2022-09-01

    19. [19]

      The NHS says the cause of ADHD is not always known; it may be caused by genetic differences and often runs in families, and it is linked to premature birth, epilepsy, brain injury and autism. confirmedas of 2025-03-19

      • ADHD in adults · NHS (nhs.uk) · 2025-03-19 · What causes ADHD; continues: "being born premature (before 37 weeks of pregnancy), having epilepsy, a brain injury and being autistic" (retrieved 2026-10-11)
    20. [20]

      For children aged 6 to 11 with ADHD, the AAP recommends FDA-approved medication together with parent training and/or behavioural classroom interventions. confirmedas of 2019-10-01

    21. [21]

      The NHS says ADHD medicines must be started and monitored by an ADHD specialist; for adults these include methylphenidate or lisdexamfetamine, and not everyone with ADHD needs or wants medicine. confirmedas of 2025-03-19

      • ADHD in adults · NHS (nhs.uk) · 2025-03-19 · Medicines (retrieved 2026-10-11)
    22. [22]

      NICE recommends methylphenidate as the first-line medicine for children aged 5 and over and young people with ADHD. confirmedas of 2019-09-13

    23. [23]

      NICE says medication should be offered to children aged 5 and over, young people and adults only if ADHD symptoms still cause significant impairment after environmental changes have been made and reviewed. confirmedas of 2019-09-13

    24. [24]

      The AAP guideline says the evidence is particularly strong for stimulant medications and sufficient but less strong for atomoxetine, extended-release guanfacine and extended-release clonidine, in that order. confirmedas of 2019-10-01

    25. [25]

      A 2018 network meta-analysis of 133 double-blind randomised trials concluded that, weighing efficacy and safety, methylphenidate in children and adolescents and amphetamines in adults are preferred first-choice medicines for short-term ADHD treatment. confirmedas of 2018-08-07

    26. [26]

      The 2018 network meta-analysis did not find sufficient data to assess ADHD medicines at 26 and 52 weeks and called for funding of research on long-term effects. confirmedas of 2018-08-07

    27. [27]

      About one third of US adults with ADHD took stimulant medication in 2023, and 71.5% of those reported difficulty getting their prescription filled in the previous 12 months because the medication was not available. confirmedas of 2024-10-10

    28. [28]

      FDA has listed a shortage of lisdexamfetamine capsules and chewable tablets since 14 July 2023; as of 9 October 2026 it remained current, with 33 of 108 product records showing limited availability and 1 unavailable. confirmedas of 2026-10-09

    29. [29]

      WHO includes burn-out in ICD-11 as an occupational phenomenon, not as a medical condition, in the chapter on factors influencing health status or contact with health services. confirmedas of 2019-05-28

    30. [30]

      The NHS says ADHD is thought to be recognised less often in women than men, possibly because women more commonly have inattentive symptoms, which can be harder to recognise. confirmedas of 2025-03-19

      • ADHD in adults · NHS (nhs.uk) · 2025-03-19 · Symptoms of ADHD (retrieved 2026-10-11)
    31. [31]

      FDA has listed a shortage of extended-release methylphenidate tablets since 26 July 2023 and of a methylphenidate extended-release film since 28 February 2025; as of 9 October 2026 both remained current, with 6 tablet products unavailable and 9 limited. confirmedas of 2026-10-09

    Revision history (1)
    1. Page created.

    Created Oct 11, 2026. Last reviewed by an editor on Oct 11, 2026. Next scheduled review: Jan 11, 2027.

    Cite this page

    "ADHD explained: symptoms, diagnosis, treatment and the 2026 picture." ContentLora, updated Oct 11, 2026. https://contentlora.com/explain/adhd-explained

    Spotted an error? Suggest a correction or emailcorrections@contentlora.com.

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