Editing Attention deficit hyperactivity disorder (section)

==Diagnosis==
<!--Use [[Diagnosis of attention deficit hyperactivity disorder]] not [[Attention deficit hyperactivity disorder#Diagnosis]] to prevent broken anchors just in case the section is renamed -->

ADHD is diagnosed by an assessment of a person's behavioural and mental development, including ruling out the effects of drugs, medications, and other medical or psychiatric problems as explanations for the symptoms.<ref name="NICE2009-part2">{{cite book |author=National Collaborating Centre for Mental Health |url=https://www.ncbi.nlm.nih.gov/books/NBK53652/ |title=Attention Deficit Hyperactivity Disorder: Diagnosis and Management of ADHD in Children, Young People and Adults |date=2009 |publisher=[[British Psychological Society]] |isbn=978-1-85433-471-8 |series=NICE Clinical Guidelines |volume=72 |location=Leicester |pages=[https://www.ncbi.nlm.nih.gov/books/NBK53663/#ch2.s8 18–26], [https://www.ncbi.nlm.nih.gov/books/NBK53663/#ch2.s41 38] |chapter=Attention Deficit Hyperactivity Disorder |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK53663/ |archive-url=https://web.archive.org/web/20160113133612/http://www.ncbi.nlm.nih.gov/books/NBK53652/ |archive-date=13 January 2016 |url-status=live |via=NCBI Bookshelf}}</ref> ADHD diagnosis often takes into account feedback from parents and teachers<ref name="Lake2011">{{cite book |vauthors=Dulcan MK, Lake MB |url={{google books|HvTa2nArhOsC|plainurl=yes}} |title=Concise Guide to Child and Adolescent Psychiatry |date=2011 |publisher=American Psychiatric Publishing |isbn=978-1-58562-416-4 |edition=4th illustrated |pages=[https://books.google.com/books?id=HvTa2nArhOsC&pg=PA34 34] |chapter=Axis I Disorders Usually First Diagnosed in Infancy, Childhood or Adolescence: Attention-Deficit and Disruptive Behavior Disorders |chapter-url={{google books|HvTa2nArhOsC |page=23|plainurl=yes}} |via=Google Books}}</ref> with most diagnoses begun after a teacher raises concerns.<ref name="Erk_2009">{{cite book |vauthors=Mayes R, Bagwell C, Erkulwater JL |title=Medicating Children: ADHD and Pediatric Mental Health |publisher=[[Harvard University Press]] |date=2009 |pages=4–24 |isbn=978-0-674-03163-0 |edition=illustrated}}</ref> While many tools exist to aid in the diagnosis of ADHD, their validity varies in different populations, and a reliable and valid diagnosis requires confirmation by a clinician while supplemented by standardised rating scales and input from multiple informants across various settings.<ref name="Peterson_2024">{{cite journal |vauthors=Peterson BS, Trampush J, Brown M, Maglione M, Bolshakova M, Rozelle M, Miles J, Pakdaman S, Yagyu S, Motala A, Hempel S |title=Tools for the Diagnosis of ADHD in Children and Adolescents: A Systematic Review |journal=[[Pediatrics (journal)|Pediatrics]] |volume=153 |issue=4 |date=April 2024 |pmid=38523599 |doi=10.1542/peds.2024-065854}}</ref>
The diagnosis of ADHD has been criticised as being subjective because it is not based on a biological test. The International Consensus Statement on ADHD concluded that this criticism is unfounded, on the basis that ADHD meets standard criteria for validity of a mental disorder established by Robins and Guze. They attest that the disorder is considered valid because: 1) well-trained professionals in a variety of settings and cultures agree on its presence or absence using well-defined criteria and 2) the diagnosis is useful for predicting a) additional problems the patient may have (e.g., difficulties learning in school); b) future patient outcomes (e.g., risk for future drug abuse); c) response to treatment (e.g., medications and psychological treatments); and d) features that indicate a consistent set of causes for the disorder (e.g., findings from genetics or brain imaging), and that professional associations have endorsed and published guidelines for diagnosing ADHD.<ref name="Faraone_2021" />

The most commonly used rating scales for diagnosing ADHD are the [[Achenbach System of Empirically Based Assessment|Achenbach System of Empirically Based Assessment (ASEBA)]] and include the [[Child Behavior Checklist|Child Behavior Checklist (CBCL)]] used for parents to rate their child's behaviour, the Youth Self Report Form (YSR) used for children to rate their own behaviour, and the Teacher Report Form (TRF) used for teachers to rate their pupil's behaviour. Additional rating scales that have been used alone or in combination with other measures to diagnose ADHD include the Behavior Assessment System for Children (BASC), Behavior Rating Inventory of Executive Function - Second Edition (BRIEF2), [[Conners Comprehensive Behaviour Rating Scale|Revised Conners Rating Scale (CRS-R)]], Conduct-Hyperactive-Attention Problem-Oppositional Symptom scale (CHAOS), Developmental Behavior Checklist Hyperactivity Index (DBC-HI), [[Disruptive Behavior Disorders Rating Scale|Parent Disruptive Behavior Disorder Ratings Scale (DBDRS)]], Diagnostic Infant and Preschool Assessment (DIPA-L), Pediatric Symptom Checklist (PSC), Social Communication Questionnaire (SCQ), Social Responsiveness Scale (SRS), Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Rating Scale (SWAN) and the [[Vanderbilt ADHD diagnostic rating scale]].<ref name="Peterson_2024a">{{Cite journal |title=ADHD Diagnosis and Treatment in Children and Adolescents |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |access-date=22 June 2024 |website=effectivehealthcare.ahrq.gov |date=2024 |language=en |doi=10.23970/ahrqepccer267 |pmid=38657097 |vauthors=Peterson BS, Trampush J, Maglione M, Bolshakova M, Brown M, Rozelle M, Motala A, Yagyu S, Miles J, Pakdaman S, Gastelum M, Nguyen BT, Tokutomi E, Lee E, Belay JZ, Schaefer C, Coughlin B, Celosse K, Molakalapalli S, Shaw B, Sazmin T, Onyekwuluje AN, Tolentino D, Hempel S |archive-url= |archive-date=}}</ref>

The ASEBA, BASC, CHAOS, CRS, and Vanderbilt diagnostic rating scales allow for both parents and teachers as raters in the diagnosis of childhood and adolescent ADHD. Adolescents may also self report their symptoms using self report scales from the ASEBA, SWAN, and the Dominic Interactive for Adolescents-Revised (DIA-R).<ref name="Peterson_2024a" /> Self-rating scales, such as the [[ADHD rating scale]] and the [[Vanderbilt ADHD diagnostic rating scale]], are used in the screening and evaluation of ADHD.<ref name="Smith(2007) in Mash & Barkley EBA">{{Cite book |title=Assessment of Childhood Disorders |vauthors=Smith BJ, Barkley RA, Shapiro CJ |publisher=[[Guilford Press]] |year=2007 |isbn=978-1-59385-493-5 |veditors=Mash EJ, Barkley RA |edition=4th |location=New York, NY |pages=53–131 |chapter=Attention-Deficit/Hyperactivity Disorder}}</ref>

Based on a 2024 systematic literature review and meta analysis commissioned by the Patient-Centered Outcomes Research Institute (PCORI), rating scales based on parent report, teacher report, or self-assessment from the adolescent have high internal consistency as a diagnostic tool meaning that the items within the scale are highly interrelated. The reliability of the scales between raters (i.e. their degree of agreement) however is poor to moderate making it important to include information from multiple raters to best inform a diagnosis.<ref name="Peterson_2024a" />

Imaging studies of the brain do not give consistent results between individuals; thus, they are only used for research purposes and not a diagnosis.<ref>{{cite web |url=http://www.merckmedicus.com/pp/us/hcp/diseasemodules/adhd/pathophysiology.jsp |work = MerckMedicus Modules |publisher=Merck & Co., Inc. |location=Whitehouse Station, NJ, USA |title=ADHD&nbsp;–Pathophysiology |archive-url=https://web.archive.org/web/20100501074844/http://www.merckmedicus.com/pp/us/hcp/diseasemodules/adhd/pathophysiology.jsp |archive-date=1 May 2010 |date=August 2002}}</ref> Electroencephalography is not accurate enough to make an ADHD diagnosis.<ref>{{cite journal |vauthors=Al Rahbi HA, Al-Sabri RM, Chitme HR |title=Interventions by pharmacists in out-patient pharmaceutical care |journal=Saudi Pharmaceutical Journal |volume=22 |issue=2 |pages=101–106 |date=April 2014 |pmid=24648820 |pmc=3950532 |doi=10.1016/j.jsps.2013.04.001}}</ref><ref>{{cite journal |vauthors=Adamou M, Fullen T, Jones SL |title=EEG for Diagnosis of Adult ADHD: A Systematic Review With Narrative Analysis |journal=[[Frontiers in Psychiatry]] |volume=11 |page=871 |date=25 August 2020 |pmid=33192633 |pmc=7477352 |doi=10.3389/fpsyt.2020.00871 |doi-access=free}}</ref><ref>{{cite journal |vauthors=Lenartowicz A, Loo SK |title=Use of EEG to diagnose ADHD |journal=[[Current Psychiatry Reports]] |volume=16 |issue=11 |page=498 |date=November 2014 |pmid=25234074 |pmc=4633088 |doi=10.1007/s11920-014-0498-0}}</ref> A 2024 systematic review concluded that the use of [[biomarker]]s such as blood or urine samples, [[Electroencephalography|electroencephalogram]] (EEG) markers, and [[neuroimaging]] such as [[Magnetic resonance imaging|MRIs]], in diagnosis for ADHD remains unclear; studies showed great variability, did not assess test-retest reliability, and were not independently replicable.<ref name="Peterson_2024" />

In North America and Australia, DSM-5 criteria are used for diagnosis, while European countries usually use the ICD-10. The DSM-IV criteria for diagnosis of ADHD is {{nowrap|3–4 times}} more likely to diagnose ADHD than is the ICD-10 criteria.<ref name="Singh_2008" /> ADHD is alternately classified as [[neurodevelopmental disorder]]<ref name="Caroline2010">{{Cite book |url=https://books.google.com/books?id=PaO3jsaGkeYC&pg=PA133 |title=Encyclopedia of Cross-Cultural School Psychology |publisher=Springer Science & Business Media |year=2010 |isbn=978-0-387-71798-2 |veditors=Caroline SC |page=133 |access-date=1 February 2016 |archive-date=22 December 2020 |archive-url=https://web.archive.org/web/20201222193428/https://books.google.com/books?id=PaO3jsaGkeYC&pg=PA133 |url-status=live }}</ref> or a [[Disruptive behavior disorder|disruptive behaviour disorder]] along with [[Oppositional defiant disorder|ODD]], [[Conduct disorder|CD]], and [[antisocial personality disorder]].<ref name="google-book-ref">{{Cite book |vauthors=Wiener JM, Dulcan MK |title=Textbook Of Child and Adolescent Psychiatry |publisher=American Psychiatric Publishing |edition=illustrated |year=2004 |isbn=978-1-58562-057-9 |url=https://books.google.com/books?id=EIgGKcp0SpkC |access-date=2 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20160506182138/https://books.google.com/books?id=EIgGKcp0SpkC |archive-date=6 May 2016}}</ref> A diagnosis does not imply a [[neurological disorder]].<ref name="NICE 2009" />

Very few studies have been conducted on diagnosis of ADHD on children younger than 7 years of age, and those that have were found in a 2024 systematic review to be of low or insufficient strength of evidence.<ref name="Peterson_2024a" /> A 2024 systematic review commissioned by the Patient-Centered Outcomes Research Institute (PCORI) highlighted that although a variety of diagnostic approaches show potential, there is substantial variability in their performance across studies. The CBCL and Disruptive Behavior Diagnostic Observation Schedule (DB-DOS) showed good performance, while BRIEF worked very well. However, there is not enough studies on children younger than 7 years of age to determine which diagnosis method is the most effective.<ref>{{Cite report |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |title=ADHD Diagnosis and Treatment in Children and Adolescents |last=Peterson |first=Bradley S. |last2=Trampush |first2=Joey |last3=Maglione |first3=Margaret |last4=Bolshakova |first4=Maria |last5=Brown |first5=Morah |last6=Rozelle |first6=Mary |last7=Motala |first7=Aneesa |last8=Yagyu |first8=Sachi |last9=Miles |first9=Jeremy |date=2024-03-25 |publisher=Agency for Healthcare Research and Quality (AHRQ) |doi=10.23970/ahrqepccer267}}</ref> The review emphasised that diagnostic accuracy often depends on the comparison group—whether children with ADHD are being distinguished from typically developing peers or from other clinically referred youth—and that multiple informants (such as parents, teachers, and the youth themselves) may be necessary to improve diagnostic accuracy due to poor-to-moderate agreement between raters.<ref name="Peterson_2024a" />

===Classification===
====Diagnostic and Statistical Manual====
As with many other psychiatric disorders, a formal diagnosis should be made by a qualified professional based on a set number of criteria. In the United States, these criteria are defined by the [[American Psychiatric Association]] in the [[Diagnostic and Statistical Manual of Mental Disorders|DSM]]. Based on the DSM-5 criteria published in 2013 and the DSM-5-TR criteria published in 2022, there are three presentations of ADHD:

# ADHD, predominantly inattentive presentation, presents with symptoms including being easily distracted, forgetful, daydreaming, disorganisation, poor sustained attention, and difficulty completing tasks.
# ADHD, predominantly hyperactive-impulsive presentation, presents with excessive fidgeting and restlessness, hyperactivity, and difficulty waiting and remaining seated.
# ADHD, combined presentation, is a combination of the first two presentations.

This subdivision is based on presence of at least six (in children) or five (in older teenagers and adults)<ref>{{cite web |title=Adult ADHD: Diagnosis |url=https://www.camh.ca/en/professionals/treating-conditions-and-disorders/adult-adhd/adult-adhd---diagnosis |access-date=17 April 2022 |website=CAMH |archive-date=21 June 2021 |archive-url=https://web.archive.org/web/20210621130901/https://www.camh.ca/en/professionals/treating-conditions-and-disorders/adult-adhd/adult-adhd---diagnosis |url-status=live }}</ref> out of nine long-term (lasting at least six months) symptoms of inattention, hyperactivity–impulsivity, or both.<ref name="DSM5" /><ref name="DSM5TR" /> To be considered, several symptoms must have appeared by the age of six to twelve and occur in more than one environment (e.g. at home and at school or work). The symptoms must be inappropriate for a child of that age<ref name="pmid21991721">{{cite journal |vauthors=Berger I |title=Diagnosis of attention deficit hyperactivity disorder: much ado about something |journal=[[Israel Medical Association Journal]] |volume=13 |issue=9 |pages=571–574 |date=September 2011 |pmid=21991721 |url=http://www.ima.org.il/FilesUpload/IMAJ/0/40/20032.pdf |access-date=23 May 2013 |url-status=live |archive-url=https://web.archive.org/web/20200728130553/https://www.ima.org.il/filesupload/imaj/0/40/20032.pdf |archive-date=28 July 2020}}</ref> and there must be clear evidence that they are causing impairment in multiple domains of life.<ref name="pmid23755024">{{cite journal |vauthors=Steinau S |title=Diagnostic Criteria in Attention Deficit Hyperactivity Disorder - Changes in DSM 5 |journal=[[Frontiers in Psychiatry]] |volume=4 |page=49 |year=2013 |pmid=23755024 |pmc=3667245 |doi=10.3389/fpsyt.2013.00049 |doi-access=free}}</ref>

The DSM-5 and the DSM-5-TR also provide two diagnoses for individuals who have symptoms of ADHD but do not entirely meet the requirements. ''Other Specified ADHD'' allows the clinician to describe why the individual does not meet the criteria, whereas ''Unspecified ADHD'' is used where the clinician chooses not to describe the reason.<ref name="DSM5" /><ref name="DSM5TR" />

====International Classification of Diseases====
In the eleventh revision of the [[International Statistical Classification of Diseases and Related Health Problems]] ([[ICD-11]]) by the [[World Health Organization]], the disorder is classified as Attention deficit hyperactivity disorder (code 6A05). The defined subtypes are ''predominantly inattentive presentation'' (6A05.0); ''predominantly hyperactive-impulsive presentation'' (6A05.1); and ''combined presentation'' (6A05.2). However, the ICD-11 includes two residual categories for individuals who do not entirely match any of the defined subtypes: ''other specified presentation'' (6A05.Y) where the clinician includes detail on the individual's presentation; and ''presentation unspecified'' (6A05.Z) where the clinician does not provide detail.<ref name="ICD-11">{{cite encyclopedia |title=6A05 Attention deficit hyperactivity disorder |date=February 2022<!-- The most recent update as of the access date --> |orig-date=2019<!-- This is when it was adopted by the World Health Assembly --> |url=https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/821852937 |encyclopedia=International Classification of Diseases |edition=11th |access-date=8 May 2022 |archive-date=1 August 2018 |archive-url=https://archive.today/20180801205234/https://icd.who.int/browse11/l-m/en%23/http://id.who.int/icd/entity/294762853#/http://id.who.int/icd/entity/821852937 |url-status=live}}</ref>

In the tenth revision ([[ICD-10]]), the symptoms of ''hyperkinetic disorder'' were analogous to ADHD in the ICD-11. When a [[conduct disorder]] <!-- a type of disorder, its not CD --> (as defined by ICD-10)<ref name="ICD10">{{cite book |title=International Statistical Classification of Diseases and Related Health Problems 10th Revision |year=2010 |publisher=World Health Organisation |chapter=F90 Hyperkinetic disorders |chapter-url=http://apps.who.int/classifications/icd10/browse/2010/en#/F90 |access-date=2 November 2014 |url-status=live |archive-date=2 November 2014 |archive-url=https://web.archive.org/web/20141102133725/http://apps.who.int/classifications/icd10/browse/2010/en#/F90}}</ref> is present, the condition was referred to as ''hyperkinetic conduct disorder''. Otherwise, the disorder was classified as ''disturbance of activity and attention'', ''other hyperkinetic disorders'' or ''hyperkinetic disorders, unspecified''. The latter was sometimes referred to as ''hyperkinetic syndrome''.<ref name="ICD10" />

====Social construct theory====
The [[social construct theory of ADHD]] suggests that, because the boundaries between normal and abnormal behaviour are socially constructed (i.e. jointly created and validated by all members of society, and in particular by [[physician]]s, parents, teachers, and others), it then follows that subjective valuations and judgements determine which diagnostic criteria are used and thus, the number of people affected.<ref>{{cite journal |vauthors=Parens E, Johnston J |title=Facts, values, and attention-deficit hyperactivity disorder (ADHD): an update on the controversies |journal=Child and Adolescent Psychiatry and Mental Health |volume=3 |issue=1 |page=1 |date=January 2009 |pmid=19152690 |pmc=2637252 |doi=10.1186/1753-2000-3-1 |doi-access=free}}</ref> [[Thomas Szasz]], a supporter of this theory, has argued that ADHD was "invented and then given a name".<ref>{{Cite book |vauthors=Szasz T |chapter=Psychiatric Medicine: Disorder |chapter-url={{google books|29HP1q6JrgYC |page=77|plainurl=yes}} |title=Pharmacracy: medicine and politics in America |url={{google books|29HP1q6JrgYC|plainurl=yes}} |via=Google Books |publisher=Praeger |location=Westport, CT |year=2001 |pages=[{{google books|29HP1q6JrgYC |page=101|plainurl=yes}} 101] |isbn=978-0-275-97196-0 |quote=Mental diseases are ''invented'' and then given a name, for example attention deficit hyperactivity disorder (ADHD).}}</ref>

===Adults===
{{Main|Adult attention deficit hyperactivity disorder}}

Adults with ADHD are diagnosed under the same criteria, including that their signs must have been present by the age of six to twelve. The individual is the best source for information in diagnosis, however others may provide useful information about the individual's symptoms currently and in childhood; a family history of ADHD also adds weight to a diagnosis.<ref name="Kooij_2010" />{{rp|7,9}} Certain assessments, such as the [[Wender Utah Rating Scale]] (WURS), attempt to assess these childhood ADHD symptoms by having adults retrospectively recall their experiences as children.<ref name="pmid38369740">{{cite journal |vauthors=Caroline S SS, Sudhir PM, Mehta UM, Kandasamy A, Thennarasu K, Benegal V |title=Assessing Adult ADHD: An Updated Review of Rating Scales for Adult Attention Deficit Hyperactivity Disorder (ADHD) |journal=[[Journal of Attention Disorders]] |volume=28 |issue=7 |pages=1045–1062 |date=May 2024 |pmid=38369740 |doi=10.1177/10870547241226654}}</ref> While the core symptoms of ADHD are similar in children and adults, they often present differently in adults than in children: for example, excessive physical activity seen in children may present as feelings of restlessness and constant mental activity in adults.<ref name="Kooij_2010" />{{rp|6}}

Worldwide, it is estimated that 2.58% of adults have persistent ADHD (where the individual currently meets the criteria and there is evidence of childhood onset), and 6.76% of adults have symptomatic ADHD (meaning that they currently meet the criteria for ADHD, regardless of childhood onset).<ref name="Song_2021">{{cite journal |vauthors=Song P, Zha M, Yang Q, Zhang Y, Li X, Rudan I |title=The prevalence of adult attention-deficit hyperactivity disorder: A global systematic review and meta-analysis |journal=[[Journal of Global Health]] |volume=11 |page=04009 |date=February 2021 |pmid=33692893 |pmc=7916320 |doi=10.7189/jogh.11.04009 |publisher=International Global Health Society |oclc=751737736 |eissn=2047-2986}}</ref> In 2020, this was 139.84 million and 366.33 million affected adults respectively.<ref name="Song_2021" /> Around 15% of children with ADHD continue to meet full DSM-IV-TR criteria at 25 years of age, and 50% still experience some symptoms.<ref name="Kooij_2010" />{{rp|2|quote=In the meta-analysis of these data from Faraone and colleagues it was concluded that about 15% retain the full diagnosis by age 25 years, with a further 50% in partial remission, indicating that around two-thirds of children with ADHD continue to have impairing levels of ADHD symptoms as adults.}} {{As of|2010}}, most adults remain untreated.<ref name="pmid21494335">{{cite journal |vauthors=Culpepper L, Mattingly G |title=Challenges in identifying and managing attention-deficit/hyperactivity disorder in adults in the primary care setting: a review of the literature |journal=Primary Care Companion to the Journal of Clinical Psychiatry |volume=12 |issue=6 |pages=PCC.10r00951 |year=2010 |pmid=21494335 |pmc=3067998 |doi=10.4088/PCC.10r00951pur}}</ref> Many adults with ADHD without diagnosis and treatment have a disorganised life, and some use [[Substance abuse|non-prescribed drugs]] or [[Alcoholism|alcohol]] as a coping mechanism.<ref name="Art.218">{{cite journal |vauthors=Gentile JP, Atiq R, Gillig PM |title=Adult ADHD: Diagnosis, Differential Diagnosis, and Medication Management |journal=Psychiatry |volume=3 |issue=8 |pages=25–30 |date=August 2006 |pmid=20963192 |pmc=2957278 |quote=likelihood that the adult with ADHD has developed coping mechanisms to compensate for his or her impairment}}</ref> Other problems may include relationship and job difficulties, and an increased risk of criminal activities.<ref>{{cite journal |vauthors=Mohr-Jensen C, Steinhausen HC |title=A meta-analysis and systematic review of the risks associated with childhood attention-deficit hyperactivity disorder on long-term outcome of arrests, convictions, and incarcerations |journal=[[Clinical Psychology Review]] |volume=48 |pages=32–42 |date=August 2016 |pmid=27390061 |doi=10.1016/j.cpr.2016.05.002}}</ref><ref name="Kooij_2010" />{{rp|6|quote=Typically, adults with ADHD will not settle after the age of 30 but continue to change and/or lose jobs and relationships, either through boredom or being fired. They are usually underachievers with an estimated annual twenty two days of excess lost role performance. As a consequence relationships and jobs are often short lived. Relationships that last are often impaired due to the inability to listen with concentration to the spouse, not finishing or procrastinating tasks, often being on a 'short fuse' and interrupting conversations. ... Criminality in adulthood is predicted by ADHD and comorbid conduct disorder in childhood, especially with substance abuse and anti-social personality disorder in adulthood. ... ADHD patients are significantly more arrested, convicted, and incarcerated compared to normal controls, and ADHD is increasingly diagnosed in adults in forensic psychiatry.}} Associated mental health problems include depression, anxiety disorders, and learning disabilities.<ref name="Art.218" />

Some ADHD symptoms in adults differ from those seen in children. While children with ADHD may climb and run about excessively, adults may experience an inability to relax, or may talk excessively in social situations.<ref name="Kooij_2010" />{{rp|6}} Adults with ADHD may start relationships impulsively, display sensation-seeking behaviour, and be short-tempered.<ref name="Kooij_2010" />{{rp|6}} Addictive behaviour such as substance abuse and [[gambling]] are common.<ref name="Kooij_2010" />{{rp|6}} This led to those who presented differently as they aged having outgrown the DSM-IV criteria.<ref name="Kooij_2010" />{{rp|5–6}} The DSM-5 criteria does specifically deal with adults unlike that of DSM-IV, which does not fully take into account the differences in impairments seen in adulthood compared to childhood.<ref name="Kooij_2010" />{{rp|5}}

For diagnosis in an adult, the presence of symptoms since childhood is generally required. However, a proportion of adults who meet the criteria for ADHD in adulthood would not have been diagnosed with ADHD as children. Most cases of late-onset ADHD develop the disorder between the ages of 12–16 and may therefore be considered early adult or adolescent-onset ADHD.<ref>{{cite journal |vauthors=Asherson P, Agnew-Blais J |title=Annual Research Review: Does late-onset attention-deficit/hyperactivity disorder exist? |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=60 |issue=4 |pages=333–352 |date=April 2019 |pmid=30843223 |doi=10.1111/jcpp.13020 |doi-access=free}}</ref>

===Differential diagnosis===
{| class="wikitable floatright" style="width:40em; border:solid 1px #999;"
|-
|+ Symptoms related to other disorders<ref name="BBDADHD">{{Cite journal |author1=Consumer Reports |author1-link=Consumer Reports |author2=Drug Effectiveness Review Project |author2-link=Drug Effectiveness Review Project |date=March 2012 |title=Evaluating Prescription Drugs Used to Treat: Attention Deficit Hyperactivity Disorder (ADHD) Comparing Effectiveness, Safety, and Price |journal=Best Buy Drugs |page=2 |url=http://www.consumerreports.org/health/resources/pdf/best-buy-drugs/ADHDFinal.pdf |access-date=12 April 2013 |url-status=live |archive-url=https://web.archive.org/web/20121115014628/http://www.consumerreports.org/health/resources/pdf/best-buy-drugs/ADHDFinal.pdf |archive-date=15 November 2012}}</ref>
|-
! width="35%" |Depressive disorder
! width="30%" |Anxiety disorder
! width="35%" |Bipolar disorder
|-
|
*feelings of hopelessness, [[low self-esteem]], or unhappiness
*loss of interest in hobbies or regular activities
*[[Fatigue (medical)|fatigue]]
*sleep problems
*difficulty maintaining [[attention]]
*change in [[appetite]]
*[[irritability]] or [[hostility]]
*low tolerance for [[Stress (psychological)|stress]]
*thoughts of death
*unexplained pain
|
*persistent feeling of anxiety
*[[irritability]]
*occasional feelings of [[panic]] or [[fear]]
*[[hypervigilance]]
*inability to pay attention
*tire easily
*low tolerance for [[Stress (psychological)|stress]]
*difficulty maintaining attention
|
'''in manic state'''
*excessive [[happiness]]
*hyperactivity
*[[racing thoughts]]
*[[aggression]]
*excessive talking
*[[grandiose delusions]]
*decreased need for sleep
*inappropriate social behaviour
*difficulty maintaining attention
'''in depressive state'''
*same symptoms as in depression section
|}

The DSM provides [[differential diagnosis|differential diagnoses]] – potential alternate explanations for specific symptoms. Assessment and investigation of clinical history determines which is the most appropriate diagnosis. The DSM-5 suggests [[oppositional defiant disorder]], [[intermittent explosive disorder]], and other disorders such as [[stereotypic movement disorder]] and [[Tourette syndrome]], in addition to specific learning disorder, [[intellectual disability]], [[autism]], [[reactive attachment disorder]], [[anxiety disorder]]s, depressive disorders, [[bipolar disorder]], [[disruptive mood dysregulation disorder]], [[substance use disorder]], [[personality disorder]]s, [[psychotic disorders]], medication-induced symptoms, and [[neurocognitive disorders]]. Many but not all of these are also common comorbidities of ADHD.<ref name="DSM5" /> The DSM-5-TR also suggests [[post-traumatic stress disorder]].<ref name="DSM5TR" />

Symptoms of ADHD that particularly relate to disinhibition and [[irritability]] in addition to low-mood and self-esteem as a result of symptom expression might be confusable with [[dysthymia]] and [[bipolar disorder]] as well as with [[borderline personality disorder]], however they are comorbid at a significantly increased rate relative to the general population.<ref name="Kooij_2010" />{{rp|10|Because adults with ADHD often exhibit low self-esteem, low mood, affective lability and irritability, these symptoms may sometimes be confused with dysthymia, cyclothymia or bipolar disorder and with borderline personality disorder.}} Some symptoms that are viewed superficially due to anxiety disorders, intellectual disability or the effects of substance abuse such as intoxication and [[Drug withdrawal|withdrawal]] can overlap to some extent with ADHD. These disorders can also sometimes occur along with ADHD.

Primary sleep disorders may affect attention and behaviour and the symptoms of ADHD may affect sleep.<ref name="Owens2008">{{cite journal |vauthors=Owens JA |title=Sleep disorders and attention-deficit/hyperactivity disorder |journal=[[Current Psychiatry Reports]] |volume=10 |issue=5 |pages=439–444 |date=October 2008 |pmid=18803919 |doi=10.1007/s11920-008-0070-x |s2cid=23624443}}</ref> It is thus recommended that children with ADHD be regularly assessed for sleep problems.<ref>{{cite journal |vauthors=Walters AS, Silvestri R, Zucconi M, Chandrashekariah R, Konofal E |title=Review of the possible relationship and hypothetical links between attention deficit hyperactivity disorder (ADHD) and the simple sleep related movement disorders, parasomnias, hypersomnias, and circadian rhythm disorders |journal=[[Journal of Clinical Sleep Medicine]] |volume=4 |issue=6 |pages=591–600 |date=December 2008 |pmid=19110891 |pmc=2603539 |doi=10.5664/jcsm.27356}}</ref> Sleepiness in children may result in symptoms ranging from the classic ones of yawning and rubbing the eyes, to disinhibition and inattention. [[Obstructive sleep apnea]] can also cause ADHD-like symptoms.<ref name="pmid22670023">{{cite journal |vauthors=Lal C, Strange C, Bachman D |title=Neurocognitive impairment in obstructive sleep apnea |journal=[[Chest (journal)|Chest]] |volume=141 |issue=6 |pages=1601–1610 |date=June 2012 |pmid=22670023 |doi=10.1378/chest.11-2214}}</ref>

In general, the DSM-5-TR can help distinguish between many conditions associated with ADHD-like symptoms by the context in which the symptoms arise.<ref name="DSM5TR" /> For example, children with [[Learning disability|learning disabilities]] may feel distractable and agitated when asked to engage in tasks that require the impaired skill (e.g., reading, math), but not in other situations. A person with an [[intellectual disability]] may develop symptoms that overlap with ADHD when placed in a school environment that is inappropriate for their needs. The type of inattention implicated in ADHD, of poor persistence and sustained attention, differs substantially from selective or oriented inattention seen in [[cognitive disengagement syndrome]] (CDS), as well as from rumination, reexperiencing or mind blanking seen in anxiety disorders or PTSD.

In mood disorders, ADHD-like symptoms may be limited to [[Mania|manic]] or depressive states of an episodic nature. Symptoms overlapping with ADHD in [[psychotic disorders]] may be limited to psychotic states. [[Substance use disorder]], some medications, and certain medical conditions may cause symptoms to appear later in life, while ADHD, as a [[neurodevelopmental disorder]], requires for them to have been present since childhood.

Furthermore, a careful understanding of the nature of the symptoms may help establish the difference between ADHD and other disorders.<ref name="DSM5TR" /> For example, the forgetfulness and impulsivity typical of ADHD (e.g., in completing school assignments or following directions) may be distinguished from [[Oppositional defiant disorder|opposition]] when there is no hostility or defiance, although ADHD and ODD are highly comorbid.{{cn|date=April 2025}} Tantrums may differ from the outbursts in [[intermittent explosive disorder]] if there is no aggression involved. The fidgetiness observed in ADHD may be differentiated from [[tic]]s or [[Stereotypy|stereotypies]] common in Tourette syndrome or autism.{{cn|date=April 2025}}

Also, the social difficulties often experienced by individuals with ADHD due to inattention (e.g., being unfocused during the interaction and therefore missing cues or being unaware of one's behavior)<ref>{{Cite book |last1=Barkley |first1=Russell A. |title=Taking charge of adult ADHD: proven strategies to succeed at work, at home, and in relationships |last2=Benton |first2=Christine M. |date=2022 |publisher=[[Guilford Press]] |isbn=978-1-4625-4685-5 |edition=2nd |location=New York London |pages=74–76}}</ref> or impulsivity (blurting things out, asking intrusive questions, interrupting) may be contrasted with the social detachment and deficits in understanding social cues associated with autism. Individuals with ADHD may also present signs of the social impairment or emotional and cognitive dysregulation seen in [[personality disorder]]s, but not necessarily such features as [[Borderline personality disorder|a fear of abandonment, an unstable sense of self]], [[Narcissistic personality disorder|narcissistic tendencies]], [[Antisocial personality disorder|aggressiveness]], or other personality features.<ref name="DSM5TR" />

While it is possible and common for many of these different conditions to be comorbid with ADHD, the symptoms must not be better explained by them, as per diagnostic criterion E in the DSM-5.<ref name="DSM5" /><ref name="DSM5TR" /> The symptoms must arise early in life, appear across multiple environments, and cause significant impairment. Moreover, when some of these conditions are in fact comorbid with ADHD, it is still important to distinguish them, as each may need to be treated separately.<ref>{{Cite book |last1=Barkley |first1=Russell A. |title=Taking charge of adult ADHD: proven strategies to succeed at work, at home, and in relationships |last2=Benton |first2=Christine M. |date=2022 |publisher=[[Guilford Press]] |isbn=978-1-4625-4685-5 |edition=2nd |location=New York London |chapter=Other Mental and Emotional Problems}}</ref>