Mayo Clinic information https://www.mayoclinic.org/diseases-conditions/adhd/symptoms-causes/syc-20350889
THE DESCRIPTIONS HERE ARE TAKEN FROM THE DSM-V STATISTICAL MANUEL OF MENTAL DISORDERS
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
B. Several inattentive or hyperactive-impulsive symptoms were present prior to age
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
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.
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.
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
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
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/
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.
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