Mayo Clinic information


Attention-Deficit/Hyperactivity Disorder

Diagnostic Criteria

A. A persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with

functioning or development, as characterized by (1) and/or (2):

1. Inattention: Six (or more) of the following symptoms have persisted for at least

6 months to a degree that is inconsistent with developmental level and that negatively

impacts directly on social and academic/occupational activities:

Note: The symptoms are not solely a manifestation of oppositional behavior, defiance,

hostility, or failure to understand tasks or instructions. For older adolescents

and adults (age 17 and older), at least five symptoms are required.

a. Often fails to give close attention to details or makes careless mistakes in

schoolwork, at work, or during other activities (e.g., overlooks or misses details,

work is inaccurate).

b. Often has difficulty sustaining attention in tasks or play activities (e.g., has difficulty

remaining focused during lectures, conversations, or lengthy reading).

c. Often does not seem to listen when spoken to directly (e.g., mind seems elsewhere,

even in the absence of any obvious distraction).

d. Often does not follow through on instructions and fails to finish schoolwork,

chores, or duties in the workplace (e.g., starts tasks but quickly loses focus and

is easily sidetracked).

e. Often has difficulty organizing tasks and activities (e.g., difficulty managing sequential

tasks; difficulty keeping materials and belongings in order; messy, disorganized

work; has poor time management; fails to meet deadlines).

f. Often avoids, dislikes, or is reluctant to engage in tasks that require sustained

mental effort (e.g., schoolwork or homework; for older adolescents and adults,

preparing reports, completing forms, reviewing lengthy papers).

g. Often loses things necessary for tasks or activities (e.g., school materials, pencils,

books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).

h. Is often easily distracted by extraneous stimuli (for older adolescents and

adults, may include unrelated thoughts).

i. Is often forgetful in daily activities (e.g., doing chores, running errands; for older

adolescents and adults, returning calls, paying bills, keeping appointments).

60 Neurodevelopmental Disorders

2. Hyperactivity and impulsivity: Six (or more) of the following symptoms have persisted

for at least 6 months to a degree that is inconsistent with developmental level

and that negatively impacts directly on social and academic/occupational activities:

Note: The symptoms are not solely a manifestation of oppositional behavior, defiance,

hostility, or a failure to understand tasks or instructions. For older adolescents

and adults (age 17 and older), at least five symptoms are required.

a. Often fidgets with or taps hands or feet or squirms in seat.

b. Often leaves seat in situations when remaining seated is expected (e.g., leaves

his or her place in the classroom, in the office or other workplace, or in other

situations that require remaining in place).

c. Often runs about or climbs in situations where it is inappropriate. (Note: In adolescents

or adults, may be limited to feeling restless.)

d. Often unable to play or engage in leisure activities quietly.

e. Is often “on the go,” acting as if “driven by a motor” (e.g., is unable to be or uncomfortable

being still for extended time, as in restaurants, meetings; may be

experienced by others as being restless or difficult to keep up with).

f. Often talks excessively.

g. Often blurts out an answer before a question has been completed (e.g., completes

people’s sentences; cannot wait for turn in conversation).

h. Often has difficulty waiting his or her turn (e.g., while waiting in line).

i. Often interrupts or intrudes on others (e.g., butts into conversations, games, or

activities; may start using other people’s things without asking or receiving permission;

for adolescents and adults, may intrude into or take over what others

are doing).

B. Several inattentive or hyperactive-impulsive symptoms were present prior to age

12 years.

C. Several inattentive or hyperactive-impulsive symptoms are present in two or more settings

(e.g., at home, school, or work; with friends or relatives; in other activities).

D. There is clear evidence that the symptoms interfere with, or reduce the quality of, social,

academic, or occupational functioning.

E. The symptoms do not occur exclusively during the course of schizophrenia or another

psychotic disorder and are not better explained by another mental disorder (e.g., mood

disorder, anxiety disorder, dissociative disorder, personality disorder, substance intoxication

or withdrawal).

Specify whether:

314.01 (F90.2) Combined presentation: If both Criterion A1 (inattention) and Criterion

A2 (hyperactivity-impulsivity) are met for the past 6 months.

314.00 (F90.0) Predominantly inattentive presentation: If Criterion A1 (inattention)

is met but Criterion A2 (hyperactivity-impulsivity) is not met for the past 6 months.

314.01 (F90.1) Predominantly hyperactive/impulsive presentation: If Criterion A2 (hyperactivity-

impulsivity) is met and Criterion A1 (inattention) is not met for the past 6 months.

Specify if:

In partial remission: When full criteria were previously met, fewer than the full criteria

have been met for the past 6 months, and the symptoms still result in impairment in

social, academic, or occupational functioning.

Specify current severity:

Mild: Few, if any, symptoms in excess of those required to make the diagnosis are

present, and symptoms result in no more than minor impairments in social or occupational


Moderate: Symptoms or functional impairment between “mild” and “severe” are present.

Attention-Deficit/Hyperactivity Disorder 61

Severe: Many symptoms in excess of those required to make the diagnosis, or several

symptoms that are particularly severe, are present, or the symptoms result in marked

impairment in social or occupational functioning.

Diagnostic Features

The essential feature of attention-deficit/hyperactivity disorder (ADHD) is a persistent

pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or

development. Inattention manifests behaviorally in ADHD as wandering off task, lacking

persistence, having difficulty sustaining focus, and being disorganized and is not due to

defiance or lack of comprehension. Hyperactivity refers to excessive motor activity (such as

a child running about) when it is not appropriate, or excessive fidgeting, tapping, or talkativeness.

In adults, hyperactivity may manifest as extreme restlessness or wearing others

out with their activity. Impulsivity refers to hasty actions that occur in the moment without

forethought and that have high potential for harm to the individual (e.g., darting into the

street without looking). Impulsivity may reflect a desire for immediate rewards or an inability

to delay gratification. Impulsive behaviors may manifest as social intrusiveness

(e.g., interrupting others excessively) and/or as making important decisions without consideration

of long-term consequences (e.g., taking a job without adequate information).

ADHD begins in childhood. The requirement that several symptoms be present before

age 12 years conveys the importance of a substantial clinical presentation during childhood.

At the same time, an earlier age at onset is not specified because of difficulties in establishing

precise childhood onset retrospectively. Adult recall of childhood symptoms

tends to be unreliable, and it is beneficial to obtain ancillary information.

Manifestations of the disorder must be present in more than one setting (e.g., home and

school, work). Confirmation of substantial symptoms across settings typically cannot be

done accurately without consulting informants who have seen the individual in those settings.

Typically, symptoms vary depending on context within a given setting. Signs of the

disorder may be minimal or absent when the individual is receiving frequent rewards for

appropriate behavior, is under close supervision, is in a novel setting, is engaged in especially

interesting activities, has consistent external stimulation (e.g., via electronic screens),

or is interacting in one-on-one situations (e.g., the clinician’s office).

Associated Features Supporting Diagnosis

Mild delays in language, motor, or social development are not specific to ADHD but often cooccur.

Associated features may include low frustration tolerance, irritability, or mood lability.

Even in the absence of a specific learning disorder, academic or work performance is often impaired.

Inattentive behavior is associated with various underlying cognitive processes, and individuals

with ADHD may exhibit cognitive problems on tests of attention, executive

function, or memory, although these tests are not sufficiently sensitive or specific to serve as diagnostic

indices. By early adulthood, ADHD is associated with an increased risk of suicide attempt,

primarily when comorbid with mood, conduct, or substance use disorders.

No biological marker is diagnostic for ADHD. As a group, compared with peers, children

with ADHD display increased slow wave electroencephalograms, reduced total

brain volume on magnetic resonance imaging, and possibly a delay in posterior to anterior

cortical maturation, but these findings are not diagnostic. In the uncommon cases where

there is a known genetic cause (e.g., Fragile X syndrome, 22q11 deletion syndrome), the

ADHD presentation should still be diagnosed.


Population surveys suggest that ADHD occurs in most cultures in about 5% of children

and about 2.5% of adults.

62 Neurodevelopmental Disorders

Development and Course

Many parents first observe excessive motor activity when the child is a toddler, but symptoms

are difficult to distinguish from highly variable normative behaviors before age 4

years. ADHD is most often identified during elementary school years, and inattention becomes

more prominent and impairing. The disorder is relatively stable through early adolescence,

but some individuals have a worsened course with development of antisocial

behaviors. In most individuals with ADHD, symptoms of motoric hyperactivity become

less obvious in adolescence and adulthood, but difficulties with restlessness, inattention,

poor planning, and impulsivity persist. A substantial proportion of children with ADHD

remain relatively impaired into adulthood.

In preschool, the main manifestation is hyperactivity. Inattention becomes more prominent

during elementary school. During adolescence, signs of hyperactivity (e.g., running

and climbing) are less common and may be confined to fidgetiness or an inner feeling of

jitteriness, restlessness, or impatience. In adulthood, along with inattention and restlessness,

impulsivity may remain problematic even when hyperactivity has diminished.

Risk and Prognostic Factors

Temperamental. ADHD is associated with reduced behavioral inhibition, effortful control,

or constraint; negative emotionality; and/or elevated novelty seeking. These traits

may predispose some children to ADHD but are not specific to the disorder.

Environmental. Very low birth weight (less than 1,500 grams) conveys a two- to threefold

risk for ADHD, but most children with low birth weight do not develop ADHD. Although

ADHD is correlated with smoking during pregnancy, some of this association

reflects common genetic risk. A minority of cases may be related to reactions to aspects of

diet. There may be a history of child abuse, neglect, multiple foster placements, neurotoxin

exposure (e.g., lead), infections (e.g., encephalitis), or alcohol exposure in utero. Exposure

to environmental toxicants has been correlated with subsequent ADHD, but it is not

known whether these associations are causal.

Genetic and physiological. ADHD is elevated in the first-degree biological relatives of

individuals with ADHD. The heritability of ADHD is substantial. While specific genes

have been correlated with ADHD, they are neither necessary nor sufficient causal factors.

Visual and hearing impairments, metabolic abnormalities, sleep disorders, nutritional deficiencies,

and epilepsy should be considered as possible influences on ADHD symptoms.

ADHD is not associated with specific physical features, although rates of minor physical

anomalies (e.g., hypertelorism, highly arched palate, low-set ears) may be relatively

elevated. Subtle motor delays and other neurological soft signs may occur. (Note that

marked co-occurring clumsiness and motor delays should be coded separately

[e.g., developmental



Course modifiers. Family interaction patterns in early childhood are unlikely to cause

ADHD but may influence its course or contribute to secondary development of conduct


Culture-Related Diagnostic Issues

Differences in ADHD prevalence rates across regions appear attributable mainly to different

diagnostic and methodological practices. However, there also may be cultural variation

in attitudes toward or interpretations of children’s behaviors. Clinical identification

rates in the United States for African American and Latino populations tend to be lower

than for Caucasian populations. Informant symptom ratings may be influenced by cultural

group of the child and the informant, suggesting that culturally appropriate practices

are relevant in assessing ADHD.

Attention-Deficit/Hyperactivity Disorder 63

Gender-Related Diagnostic Issues

ADHD is more frequent in males than in females in the general population, with a ratio of

approximately 2:1 in children and 1.6:1 in adults. Females are more likely than males to

present primarily with inattentive features.

Functional Consequences of

Attention-Deficit/Hyperactivity Disorder

ADHD is associated with reduced school performance and academic attainment, social rejection,

and, in adults, poorer occupational performance, attainment, attendance, and

higher probability of unemployment as well as elevated interpersonal conflict. Children

with ADHD are significantly more likely than their peers without ADHD to develop conduct

disorder in adolescence and antisocial personality disorder in adulthood, consequently

increasing the likelihood for substance use disorders and incarceration. The risk of

subsequent substance use disorders is elevated, especially when conduct disorder or antisocial

personality disorder develops. Individuals with ADHD are more likely than peers

to be injured. Traffic accidents and violations are more frequent in drivers with ADHD.

There may be an elevated likelihood of obesity among individuals with ADHD.

Inadequate or variable self-application to tasks that require sustained effort is often interpreted

by others as laziness, irresponsibility, or failure to cooperate. Family relationships

may be characterized by discord and negative interactions. Peer relationships are

often disrupted by peer rejection, neglect, or teasing of the individual with ADHD. On average,

individuals with ADHD obtain less schooling, have poorer vocational achievement,

and have reduced intellectual scores than their peers, although there is great variability. In

its severe form, the disorder is markedly impairing, affecting social, familial, and scholastic/

occupational adjustment.

Academic deficits, school-related problems, and peer neglect tend to be most associated

with elevated symptoms of inattention, whereas peer rejection and, to a lesser extent,

accidental injury are most salient with marked symptoms of hyperactivity or impulsivity.

Differential Diagnosis

Oppositional defiant disorder. Individuals with oppositional defiant disorder may resist

work or school tasks that require self-application because they resist conforming to

others’ demands. Their behavior is characterized by negativity, hostility, and defiance.

These symptoms must be differentiated from aversion to school or mentally demanding

tasks due to difficulty in sustaining mental effort, forgetting instructions, and impulsivity

in individuals with ADHD. Complicating the differential diagnosis is the fact that some

individuals with ADHD may develop secondary oppositional attitudes toward such tasks

and devalue their importance.

Intermittent explosive disorder. ADHD and intermittent explosive disorder share high

levels of impulsive behavior. However, individuals with intermittent explosive disorder

show serious aggression toward others, which is not characteristic of ADHD, and they do

not experience problems with sustaining attention as seen in ADHD. In addition, intermittent

explosive disorder is rare in childhood. Intermittent explosive disorder may be diagnosed

in the presence of ADHD.

Other neurodevelopmental disorders. The increased motoric activity that may occur in

ADHD must be distinguished from the repetitive motor behavior that characterizes stereotypic

movement disorder and some cases of autism spectrum disorder. In stereotypic

movement disorder, the motoric behavior is generally fixed and repetitive (e.g., body rocking,

self-biting), whereas the fidgetiness and restlessness in ADHD are typically generalized

and not characterized by repetitive stereotypic movements. In Tourette’s disorder,

64 Neurodevelopmental Disorders

frequent multiple tics can be mistaken for the generalized fidgetiness of ADHD. Prolonged

observation may be needed to differentiate fidgetiness from bouts of multiple tics.

Specific learning disorder. Children with specific learning disorder may appear inattentive

because of frustration, lack of interest, or limited ability. However, inattention in

individuals with a specific learning disorder who do not have ADHD is not impairing outside

of academic work.

Intellectual disability (intellectual developmental disorder). Symptoms of ADHD are

common among children placed in academic settings that are inappropriate to their intellectual

ability. In such cases, the symptoms are not evident during non-academic tasks. A

diagnosis of ADHD in intellectual disability requires that inattention or hyperactivity be

excessive for mental age.

Autism spectrum disorder. Individuals with ADHD and those with autism spectrum

disorder exhibit inattention, social dysfunction, and difficult-to-manage behavior. The social

dysfunction and peer rejection seen in individuals with ADHD must be distinguished

from the social disengagement, isolation, and indifference to facial and tonal communication

cues seen in individuals with autism spectrum disorder. Children with autism spectrum

disorder may display tantrums because of an inability to tolerate a change from their

expected course of events. In contrast, children with ADHD may misbehave or have a tantrum

during a major transition because of impulsivity or poor self-control.

Reactive attachment disorder. Children with reactive attachment disorder may show

social disinhibition, but not the full ADHD symptom cluster, and display other features

such as a lack of enduring relationships that are not characteristic of ADHD.

Anxiety disorders. ADHD shares symptoms of inattention with anxiety disorders. Individuals

with ADHD are inattentive because of their attraction to external stimuli, new

activities, or preoccupation with enjoyable activities. This is distinguished from the inattention

due to worry and rumination seen in anxiety disorders. Restlessness might be seen

in anxiety disorders. However, in ADHD, the symptom is not associated with worry and


Depressive disorders. Individuals with depressive disorders may present with inability

to concentrate. However, poor concentration in mood disorders becomes prominent

only during a depressive episode.

Bipolar disorder. Individuals with bipolar disorder may have increased activity, poor

concentration, and increased impulsivity, but these features are episodic, occurring several

days at a time. In bipolar disorder, increased impulsivity or inattention is accompanied

by elevated mood, grandiosity, and other specific bipolar features. Children with

ADHD may show significant changes in mood within the same day; such lability is distinct

from a manic episode, which must last 4 or more days to be a clinical indicator of bipolar

disorder, even in children. Bipolar disorder is rare in preadolescents, even when

severe irritability and anger are prominent, whereas ADHD is common among children

and adolescents who display excessive anger and irritability.

Disruptive mood dysregulation disorder. Disruptive mood dysregulation disorder is

characterized by pervasive irritability, and intolerance of frustration, but impulsiveness

and disorganized attention are not essential features. However, most children and adolescents

with the disorder have symptoms that also meet criteria for ADHD, which is diagnosed


Substance use disorders. Differentiating ADHD from substance use disorders may be

problematic if the first presentation of ADHD symptoms follows the onset of abuse or frequent

use. Clear evidence of ADHD before substance misuse from informants or previous

records may be essential for differential diagnosis.

Other Specified Attention-Deficit/Hyperactivity Disorder 65

Personality disorders. In adolescents and adults, it may be difficult to distinguish ADHD

from borderline, narcissistic, and other personality disorders. All these disorders tend to

share the features of disorganization, social intrusiveness, emotional dysregulation, and

cognitive dysregulation. However, ADHD is not characterized by fear of abandonment,

self-injury, extreme ambivalence, or other features of personality disorder. It may take

extended clinical observation, informant interview, or detailed history to distinguish impulsive,

socially intrusive, or inappropriate behavior from narcissistic, aggressive, or domineering

behavior to make this differential diagnosis.

Psychotic disorders. ADHD is not diagnosed if the symptoms of inattention and hyperactivity

occur exclusively during the course of a psychotic disorder.

Medication-induced symptoms of ADHD. Symptoms of inattention, hyperactivity, or

impulsivity attributable to the use of medication (e.g., bronchodilators, isoniazid, neuroleptics

[resulting in akathisia], thyroid replacement medication) are diagnosed as other

specified or unspecified other (or unknown) substance–related disorders.

Neurocognitive disorders. Early major neurocognitive disorder (dementia) and/or

mild neurocognitive disorder are not known to be associated with ADHD but may present

with similar clinical features. These conditions are distinguished from ADHD by their late



In clinical settings, comorbid disorders are frequent in individuals whose symptoms meet

criteria for ADHD. In the general population, oppositional defiant disorder co-occurs with

ADHD in approximately half of children with the combined presentation and about a

quarter with the predominantly inattentive presentation. Conduct disorder co-occurs in

about a quarter of children or adolescents with the combined presentation, depending on

age and setting. Most children and adolescents with disruptive mood dysregulation disorder

have symptoms that also meet criteria for ADHD; a lesser percentage of children

with ADHD have symptoms that meet criteria for disruptive mood dysregulation disorder.

Specific learning disorder commonly co-occurs with ADHD. Anxiety disorders and

major depressive disorder occur in a minority of individuals with ADHD but more often

than in the general population. Intermittent explosive disorder occurs in a minority of

adults with ADHD, but at rates above population levels. Although substance use disorders

are relatively more frequent among adults with ADHD in the general population, the

disorders are present in only a minority of adults with ADHD. In adults, antisocial and

other personality disorders may co-occur with ADHD. Other disorders that may co-occur

with ADHD include obsessive-compulsive disorder, tic disorders, and autism spectrum