What causes ADHD?

By far, the most common cause of ADHD is a genetic proclivity (i.e., ADHD is often inherited). Studies suggest that the heritability rate of ADHD ranges from 0.75 to 0.91. The heritability rate indicates the percentage of ADHD in an individual resulting from genetic rather than environmental factors. Thus, a heritability rate of 0.75 means that 75% of the cause of ADHD is genetic.However, ADHD can also be caused or exacerbated by other factors, such as preterm birth, anemia, medications for asthma, and other environmental factors.
These factors are discussed later.

If I have ADHD, will my child also have it?
No, not necessarily, but the chance is definitely greater
than if you did not have ADHD. For example, onethird
of fathers with a history of ADHD in childhood
have a child with ADHD. For mothers, the percentage
is somewhat lower. Sometimes, it is a male relative in
the mother’s family who has ADHD. Mothers presumably
have the ADHD gene, but they may exhibit
few or no symptoms. Nonetheless, these mothers can
pass the ADHD gene on to their children.We are still
not sure why females are less likely to have ADHD
symptoms, even when it is almost certain they have one
of the ADHD genes. In one study of ADHD adults
and controls, 43% of children with ADHD parents met
criteria for a diagnosis of ADHD, compared to 2% of
children in the control group of children who had parents
without ADHD. If your first child has ADHD, the risk
of your second child having ADHD is probably higher
than in the general population. However, predicting

the severity of ADHD or the type of ADHD that
might run in a family is not possible.

Do nongenetic risk factors for ADHD exist?
Results from a large national study performed in the
1960s indicated that a number of nongenetic factors
can affect the risk of ADHD. The children evaluated
in that study were followed from conception until 7 years
of age. Risk factors for ADHD included a history of
smoking, alcohol use, drug use or anemia during pregnancy,
breech birth, chorioamnionitis (infection of the
placenta) during labor, premature birth, and small head
size at birth. A family history of mental retardation
and low socioeconomic status also appeared to be risk
factors. Neurological problems in the first month of
life increase the risk of ADHD at age 7 years from 2% to
50%. In infancy, delayed development and increased
activity predict ADHD at age 7 years.When a 4-yearold
child has a small head size, astigmatism, or visual
motor, fine motor, or gross motor deficits, the risk of
ADHD is increased.

Psychosocial problems at home are also risk factors for
ADHD. A Hawaiian study revealed a 200% to 400%
increased risk of ADHD in children from families where
there was a lot of conflict in the home. In a Swedish
study, unsatisfactory family life was the largest risk factor
for ADHD, overriding any other medical problems.
Having a risk factor or even several risk factors does
not mean that ADHD is going to occur, but it makes
ADHD more likely than in someone who has no risk
factors. The various risk factors predispose a child to
ADHD to different degrees.


Was my child born with ADHD, or did it “develop?”
In most cases, to the extent that ADHD is a genetic
disorder, your child was born with ADHD. In other
words, the genes that contribute to the disorder were
present at birth. Some children born with the genes for
the disorder do not develop ADHD symptoms at all;
some have such slight difficulties with attention that it
goes undetected throughout their lives. Nevertheless,
the signs can appear and change over time, depending
on a variety of circumstances. Environmental factors
play a role even when the main cause is genetic. A child
with a mild disorder can subsequently manifest extreme
inattention or hyperactive behavior in the presence of
certain environmental factors, such as parental abuse or
neglect, poor living conditions, or other circumstances
that stress children emotionally. If ADHD symptoms
develop “suddenly,” it is likely that the disorder was
present but hidden, only appearing when an environmental
factor came into play.

My child with ADHD can sit and watch
TV for hours, but I have heard that watching
television can cause ADHD. Is this true?
Researchers have recently reported that for every hour
a day preschoolers watch television, their risk of developing
ADHD increases by about 10%. These new findings
are consistent with previous research showing that
television can shorten attention spans. Researchers have
speculated that TV might actually overstimulate and
permanently “rewire” the developing brain.

The newest study on TV watching assessed more
than 1000 children. Parents were questioned about the

children’s TV watching habits at 1 and 3 years of age.
They rated their children’s behavior at age 7 years on a
scale commonly used to diagnose ADHD. About 10%
met criteria for a diagnosis of ADHD, about the same
frequency as is usually found in 7-year-olds. But the
37% of 1-year-olds who watched 1 to 2 hours daily had
a 10% to 20% increased risk of attention problems; the
14% who watched 3 to 4 hours daily had a 30% to 40%
increased risk compared with children who watched no
TV. Among 3-year-olds, only 7% watched no TV, 44%
watched 1 to 2 hours daily, 27% watched 3 to 4 hours
daily, almost 11% watched 5 to 6 hours daily, and
about 10% watched 7 or more hours daily. These children
too were at increased risk for ADHD, and the
risk was proportionate to how much TV they watched.

Although the research has been done on TV watching,
the effects of any repetitive non-educational activity or
electronic device, such as playing video games, may be the same.

The TV research is compelling enough that the American
Academy of Pediatrics recommends that parents
do not permit children under 2 years of age to watch
television because of concerns that it affects early brain
growth and the development of social, emotional, and
cognitive skills. And there are many other reasons
that children should not watch television. For example,
TV watching has been associated with obesity and
aggressiveness. So, even if it is one of the places your
ADHD child will sit quietly, it is best to limit TV
watching. You need to be creative about finding other
things your child would like to do. Reading to your
child or encouraging your child to read alone, even if
he is reading sports magazines or comic books, is a
better alternative.
Read More: What causes ADHD?

Does having ADHD mean that something is fundamentally wrong with my child’s brain?

ADHD is a biological, brain-based problem, but that’s not the same as saying that something is wrong with your child’s brain. There’s a big difference between damage and dysfunction. Damage causes problems with the “hardware” or the basic brain structures. That’s not what happens in ADHD. Although research data show that some brain structures, particularly the caudate, the corpus callosum (which allows the two hemispheres to “talk” to each other), and the cerebellum may be smaller in children with ADHD, but there is no indication that damage per se is present. In ADHD the primary problem is with the “software”: the wiring or the connections in the brain. The problem with the connections most likely can be traced to atypical amounts of specific neurotransmitters, either individually or in relation to one another.

One recent imaging study showed that children with
ADHD have relative cortical thinning in regions important
for attention. Children with persistent ADHD had
“fixed” thinning of areas of the frontal cortex, which may
compromise the maturation of attentional systems. On
the other hand, cortical thickness normalized in children
who “outgrow” their ADHD.


Famous people who have or have had ADHD

Most certainly ADHD has affected the lives of all
kinds of people including authors, inventors, military
leaders, statesmen, composers, athletes, and actors and
actresses. The following list includes individuals who
may or may not have had diagnosed ADHD but who
most certainly exhibited behavior that indicates the
possible presence of ADHD or other learning disabilities.
For example, Danny Glover, Bill Cosby,Tom Cruise, Jim
Carrey, Robin Williams, Nolan Ryan, Jason Kidd, and
Magic Johnson are all individuals who have been
described as having ADHD symptoms. Many very successful
entrepreneurs, such as Walt Disney and Malcolm
Forbes, have also proved that their ability to “think
outside the box” was perhaps a more positive consequence
of ADHD. In fact, many individuals who have
excelled at multitasking may have been using features
of their ADHD in a positive way; their difficulties in
focusing on a single task improved their ability to handle
many tasks at once.
Read More: Does having ADHD mean that something is fundamentally wrong with my child’s brain?

What genes are involved in ADHD?

You may be aware that many functions in our body, including production of hormones and other body and brain chemicals, are controlled by specific genes—the molecules of DNA that tell our cells how to develop and behave. You may not, however, have a clear idea of how this really works, and the fact is that scientists did not either until fairly recently. Mapping the human genome has helped determine some of the genes controlling specific functions, but many genes affect body systems in ways that scientists have yet to figure out.

In some cases, multiple genes may be involved in complex interactions to cause an organ or a system to function properly (or improperly, as in the case of ADHD and many other disorders).

Genetic studies of ADHD have focused largely on genes
involved in controlling the neurotransmitter dopamine
(discussed in Question 51). This is logical because medications
that increase dopamine are effective treatments
for ADHD. Furthermore, brain-imaging studies have
identified abnormalities in the dopamine-rich frontal
and striatal regions in individuals with ADHD. In animal
models used to investigate ADHD, “knock-out”
mice—mice missing a gene important for increasing
dopamine—are hyperactive and do not respond to stimulant
treatment. Their dopamine can not be increased,
and they remain hyperactive.

Currently the genes most likely to cause ADHD are
thought to involve dopamine regulation. The dopamine
transporter (DAT) gene is the prime candidate. This
gene regulates the amount of dopamine in the synapse

by determining how much dopamine is reabsorbed
into the presynaptic neurons. In controls, the dopamine
transporter keeps the level of dopamine in the synapse
relatively high. In ADHD, the DAT “overfunctions”
and lowers the level of synaptic dopamine. Stimulants
inhibit DAT. As a result, more dopamine remains in
the synapse. Other possible causal
genes control postsynaptic dopamine receptors. They
affect the sensitivity of the receptors to dopamine. It
may take more dopamine to activate the postsynaptic
receptors in children with ADHD.

So what does this knowledge mean for treating children
with ADHD? First, it may help scientists design
better medications for treating ADHD. They can target
the cause of the neurotransmitter problem. Second,
scientists can work toward treatments, called gene
therapy, that correct the genetic abnormalities by replacing
the abnormal gene. Gene treatment is currently
being tried for a number of serious progressive neurological
disorders.
Read More:What genes are involved in ADHD?

ADHD Diagnosing

What are the essential elements of a thorough evaluation to diagnose ADHD?
A thorough evaluation of ADHD requires the recording of a detailed history from parents, a discussion with or observation of the affected child, and some backup evidence from someone outside the home. A qualified doctor can accomplish this at an appointment with you and your child. Although the diagnosis will generally be apparent from a child’s history, an interviewer most likely will ask you, your child, and your child’s teachers to complete appropriate questionnaires.

A detailed history is essential to diagnosing ADHD. It
should include information about your child’s birth;
illnesses; early language and motor milestones; infant,

toddler, and preschool years; educational progress and
motivation; homework habits; social interactions and
interests; and hobbies and extracurricular activities. A
family medical and social history is also important.
A detailed history will often include anecdotes that give
the doctor a more complete picture of your child’s past
and present.

The diagnosis of ADHD requires that the child have
symptoms that interfere in at least two settings. By definition,
outside sources are required. Although getting a
description directly from a teacher—by questionnaire or
in person—is useful, parents’ description of what they
have been told about classroom behavior often suffices.
Sometimes, teacher questionnaires are useful not only
for diagnosis, but to show parents how a teacher rates
their child’s attention and behavior in a quantitative,
rather than a qualitative or descriptive way (such as they
would hear at a parent–teacher conference).

A doctor will also try to obtain a complete “picture” of
your child. This may involve performing a physical
examination, asking questions about school and outside
interests, or asking your child to do some simple tasks
(e.g., walking on toes and heels or drawing a picture).
The objective is to develop an accurate sense of your
child for diagnostic purposes.

Whom do I consult to get a proper diagnosis of ADHD?
A number of different kinds of doctors can diagnose
ADHD.Which type you choose to examine your child
depends in part on your access to subspecialists and in
part on the degree of ADHD and the presence of
accompanying disorders. A regular pediatrician or a
developmental pediatrician (a pediatrician who specializes

in learning issues) can generally manage a child with
relatively mild ADHD. Both neurologists and psychiatrists
diagnose and treat children with ADHD. Often,
they see children whose ADHD is complicated by other
medical or psychiatric problems. Pediatricians may refer
a patient to either a neurologist or a psychiatrist when
the diagnosis is unclear or when they feel that adequately
managing an affected child is becoming difficult. A
psychiatrist might be a particularly good option for a
child with comorbid problems involving oppositional
behavior, anxiety, or mood. Conversely, a neurologist
might be the right choice for a child with comorbid tics,
Tourette’s syndrome, or a specific neurological problem
(e.g., seizures).

Although psychologists can not prescribe medication,
they can diagnose and treat problems associated with
ADHD. However, several types of psychologists are
available, and their methods of assessment will differ.
Clinical psychologists may use techniques similar to
those of a psychiatrist. They will interview parents and
child, gaining both historical and current information
about developmental, academic, social, and emotional
issues and other aspects of the child’s behavior. Other
psychologists, usually educational psychologists or neuropsychologists,
will use more quantitative measurements
to make a diagnosis. Besides following the more typical
interview procedures, these clinicians will perform
several hours of testing to arrive at a diagnosis. Most
certainly, significant school difficulties or outstanding
social and emotional issues are symptoms that may warrant
a more complete assessment by a psychologist, either
through the board of education or on a private basis. In
this way, a fuller picture of a child’s particular strengths
and weaknesses can be obtained.


I took my child to a doctor who made the
diagnosis in 30 minutes. Can doctors really
make a diagnosis of ADHD that quickly?
Yes. Although parents may have difficulty understanding
this, professionals may be able to make the diagnosis
of ADHD quite quickly. First, as qualified professionals,
they see many children with the same set of critical
characteristics. Similar to diagnosing a medical condition,
such as diabetes, a personal history in combination
with symptoms may quickly point to the right
diagnosis. In fact, a child’s personal history alone is often
the most important part of the diagnosis. In addition,
if you and your child have provided the doctor with
completed questionnaires that point out problems with
inattention, hyperactivity, or impulsivity, the diagnosis
is often immediately apparent. Very often the history is
confirmed by a child’s unruly behavior in the office:
however, the key element of the diagnosis is the history,
not the inappropriate office behavior.
Read More: ADHD Diagnosing

Do children outgrow ADHD?

Many children do outgrow ADHD. However, the latest data suggest that 50% to 70% of children continue to have some symptoms of ADHD in adolescence, and as many as 50% have persistent ADHD in adulthood.

However, even in persistent cases, the number of
symptoms decrease during adolescence and usually
decrease further in adulthood. The types of symptoms
also change. Hyperactivity and impulsivity tend to disappear, although adults with ADHD will often comment on their mental as opposed to physical restlessness.

From a biological vantage point, the reduction of symptoms
probably reflects brain maturation that continues
through adolescence and beyond.

What parts of the brain are affected in ADHD?
In studies of ADHD children, the structures that most
often have been found to play a role are the frontal
lobes, the striatum (particularly the caudate), and the
connection between these structures, which is called
the frontostriatal circuitry. More recently, the cerebellum
has also been found to play a role in ADHD.

If you are not a neurologist, that explanation probably
does not mean much, so here is a quick lesson in brain
anatomy and function. Your brain is made up of four
lobes: frontal, parietal, temporal, and occipital. By and
large, the frontal lobes control executive functioning

(e.g., planning, organizing, starting, persisting, shifting,
and inhibiting impulsive behaviors). The parietal
lobes control sensory functions and spatial skills (especially
the right parietal lobe). The temporal lobes control
language comprehension and memory, and the
occipital lobes control vision. The left frontal lobe has
the bigger effect on language-related executive functions,
and the right frontal lobe has more of an influence
on spatial executive function.

The striatum is made up of a number of structures
deep within the brain, the caudate being the most
active in ADHD. In healthy individuals, the striatum
is rich in dopamine. Some structures in the striatum
play a significant role in motor function. Parts of the
striatum are low in dopamine in such movement disorders
as Parkinson’s disease, leading to tremors and very
slow movements. Parts of the striatum have also been
found to be involved in tic disorders.


The frontostriatal circuitry forms the connection between
the frontal lobes and parts of the striatum. Brain cells
connect these structures, and the connection is maintained
by information passed between the cells via neurotransmitters.
Finally, the cerebellum is part of the hindbrain and has
been thought to primarily handle coordination. However,
recent studies suggest it plays an important role
in cognitive functions, such as language and attention,
as well as motor planning. Cerebellar striatal frontal
circuitry may also play a role in ADHD.

Where in the brain do neurotransmitters have their effects?
Neurotransmitters are chemicals in your brain that
pass along information from one cell to another. Neurotransmitters
act in the synapse, the space between
two brain cells (neurons). Neurotransmitters released

by presynaptic neurons act on receptors on postsynaptic
neurons. The amount of neurotransmitter
in the synaptic space and the sensitivity of the
postsynaptic cell receptors determine the neurotransmitter’s
effect on the postsynaptic brain cell.

There are many different neurotransmitters. Although
dopamine is probably the neurotransmitter that is
maximally involved in ADHD, norepinephrine and
serotonin probably play lesser roles. The relative balance
among these neurotransmitters may be as important
as their absolute amounts. Dopamine is the main

neurotransmitter in the striatum, while norepinephrine
is the main neurotransmitter in the frontal lobe.
Read More: Do children outgrow ADHD?

Does everyone with attention problems or hyperactivity have ADHD?

No. There are many potential causes for behaviors similar
to that seen in ADHD. Children with language
disorders who have difficulty understanding and/or
expressing themselves can appear inattentive. Their experience may be similar to listening to a foreign language
in which words are picked up only here and there.

Because they do not always understand what a teacher
is saying, such children lose their focus. Consequently,
deciding whether a child with language problems also
has ADHD can sometimes be difficult. Some children
with specific medical problems may also appear to be
inattentive. For example, thyroid problems can cause
attention difficulties. On the one hand, too little thyroid
hormone may cause a child to become inattentive; on
the other, too much thyroid hormone may cause hyperactivity.

Children with seizures may appear inattentive,
but this usually occurs irregularly and only when the
seizures are occurring. Children with sleep problems
may also appear inattentive because they are so tired
during the day. A child with any one of a variety of
emotional difficulties may also appear unable to concentrate
or may become hyperactive. Children with
anxiety or depression sometimes appear preoccupied or
distracted. In addition, unlike adults, depressed children
may become quite agitated or restless, which can be
mistaken for hyperactivity.


As a rule, children with ADHD tend to be distracted
by outside stimuli. In contrast, a child with obsessivecompulsive
disorder or a psychotic illness, for example,
may be distracted by internal events, recurring thoughts,
and excessive worry. However, a casual observer cannot
always tell the difference by the child’s behavior, so it is
difficult to correctly identify the source of the problem
without careful assessment.

Inattentiveness and hyperactivity also can be side effects
of medications. This is particularly common with some
of the medications used for treating asthma, particularly
theophylline and steroids. Antiseizure medicines can
also interfere with attention.

In short, attention problems and hyperactivity are not
automatically signs of ADHD, so you should not assume
your child has ADHD because you see these behaviors.
The child should be assessed by a professional trained to
recognize the origins of behavioral problems so that the
real cause or causes can be determined.

Does gender have an effect on ADHD in children?
Most studies indicate that more boys than girls have
ADHD. The ratio is probably 2–3:1 in school-age children.
One study that researched the frequency of ADHD
in school-aged children in the United States found the
rate in boys was 9% compared to a rate of 3% in girls.
Age seems to have an effect on the gender ratio. The
male:female ratio drops in adolescence toward 1:1. In
fact, some adult studies even suggest that women have
ADHD more often than men. As hyperactivity lessens,
the inattentive form of ADHD more commonly seen
in girls may persist and equalize the ratio.


Bear in mind, however, that these study results are
determined by the detection of ADHD. Gender ratios
may be affected by referral practices. Among children
referred to child psychiatrists or psychologists, the
boy–girl ratio varies from 3:1 to 9:1, whereas in community
surveys of school-age children, it is closer to
2:1. More severely or obviously affected children are
probably referred to a specialist and are usually boys.
It is possible, however, that ADHD goes undetected in
girls more often than it does in boys. In this regard, it
is important to note that boys and girls tend to have
different types of ADHD. Boys more often have the
hyperactive–impulsive type or the combined type,
whereas girls more often have the inattentive type. Some
people suggest that this difference affects the frequency
with which ADHD is picked up. In other words, boys
could receive diagnoses more often because they are
more vocal, their problematic behavior is more obvious,
and they are more troublesome for their teachers and
families. Although girls tend to be affected less often
than are their male peers, some studies suggest that
those with diagnosed ADHD tend to be less bright
and have more academic difficulties than do boys with
ADHD. It is possible that very bright girls simply
compensate better and their ADHD goes undetected.
Read More: Does everyone with attention problems or hyperactivity have ADHD?

Different types of ADHD

Yes. The DSM-IV-TR identifies three subtypes of
ADHD. Some children have symptoms that
suggest a mainly hyperactive–impulsive type. To meet
criteria for this subtype, a child must exhibit six or
more symptoms (including restlessness, frequent interrupting, or talking excessively; see Table 2 for the list of core symptoms). The second subtype emphasizes inattention. To have a diagnosis of this subtype of ADHD, a child must have difficulty following directions, fail to pay close attention to details, be forgetful in daily activities, or become easily distracted. In the third subtype, the combined type, a child must display six or more symptoms of both inattention and of hyperactivity–impulsivity.

At what age does ADHD most often surface?
The disorder affects individuals of all ages. Of the millions
of visits for ADHD to community physicians,
about 5% are preschoolers, approximately 66% were
elementary school-age, 20% were teenagers, and 15%
were adults. ADHD is, however, most often diagnosed
in elementary school-age children. Some children are
diagnosed later during their junior high school and
high school years. It also is not unusual for individuals
to receive their first diagnosis of ADHD as adults.

Interestingly, many parents first recognize that they
have ADHD when it is diagnosed in their child. As
this disorder was not diagnosed very frequently years
ago, many individuals went through their school years
with undiagnosed ADHD. Subsequently, when parents
see their children experiencing similar difficulties,
they remember their own history, are able to relate,
and confirm their own undiagnosed disorder.

ADHD can be diagnosed in preschoolers. Indeed, the
peak age of onset, which is different from the age at

diagnosis, may be between ages 3 and 4. Not surprisingly,
severity affects the age at which ADHD is first
noticed, with those more severely affected presenting
at a younger age.



DSM-IV-TR Core Symptoms of ADHD in Children Hyperactivity–Impulsivity
• Often fails to pay attention to details or makes careless mistakes in schoolwork,
work, or other activities
• Often has difficulty in sustaining attention in tasks or play
• Often does not listen when spoken to directly
• Often does not follow through on instructions and fails to finish a project, etc.
• Often has difficulty in organizing tasks and activities
• Often avoids, dislikes, or is reluctant to engage in tasks that require sustained
mental effort
• Often loses things necessary for tasks or activities
• Is often distracted by extraneous stimuli
• Is often forgetful in daily activities

Hyperactivity
• Often fidgets with hands or feet or squirms in seat
• Often leaves seat in classroom or in other situations in which it is inappropriate;
in adults or adolescents, may be limited to subjective feelings of restlessness
• Often runs or climbs excessively in situations in which it is inappropriate; in adolescents
or adults, may be limited to subjective feelings of restlessness
• Often has difficulty in playing or engaging in leisure activities quietly
• Is often “on the go” or acts as if “driven by a motor”
• Often talks excessively

Impulsivity
• Often blurts out answers before questions have been completed
• Often has difficulty in awaiting turn
• Often interrupts or intrudes on others
• Some hyperactive–impulsive or inattentive symptoms that caused impairment present
before age 7
• Some impairment from the symptoms present in two or more settings (school,
work, home)
• Clear evidence of significant impairment in social, academic, or occupational
functioning
• Symptoms not accounted for by another disorder and do not occur exclusively during
another disorder
Read More: Different types of ADHD

What Are ADHD Symptoms?

At what age might I begin to worry about whether my child has ADHD?
Can ADHD be diagnosed in a preschooler?

ADHD can be diagnosed in a child as young as 3 years of age. Signs of ADHD in preschoolers may include a noticeably high activity level, inability to persist with tasks, problems in following group instructions, poor behavior modulation, difficulties with social interactions, unending curiosity, excessive aggression or destructive play, silliness, bossiness, and impulsivity. Preschoolers
with ADHD may have sleep problems, such as restless
or decreased sleep. In addition, argumentative behavior
and temper tantrums may be more common in preschoolers
with ADHD. These children may also be quite
immature, frequently demonstrating off-task or inappropriate
behaviors. All of this can contribute to conflicts
within the family, ranging from battles with siblings and
parents to difficulties in keeping baby-sitters.

Do the symptoms of ADHD change as children mature?
Yes. Although some symptoms persist, many symptoms
of ADHD change with development. For example,

hyperactivity diminishes in some children after elementary
school. Many people think that the hormonal
changes of puberty are responsible for this, although we
do not understand the mechanism. Older children may
have either outgrown their hyperactivity or found ways
in which to channel it. A sense of inner restlessness may
replace the hyperactivity. In the preteen and adolescent
years, poor grades, inability to sustain attention, difficulties
in maintaining social relationships, disorganization,
and risk-taking behavior may surface as primary symptoms.

At school, ADHD may show up more as written
work becomes increasingly complex and a teenager is
required to plan ahead for long-term assignments. Socially,
the range of accepted behavior in many ways is narrowed
by the unwritten rules of a teenager’s peer group.

The difficulties with emotional self-control and interpersonal
communication common in ADHD makes
these teenagers appear more immature and clumsy
among their peers. Their impulsivity may cause them to
blurt out answers inappropriately or to interrupt conversations.
They can become disruptive in the classroom
or even be perceived as the “class clown.” This can result
in peer rejection and subsequent distress in ADHD children.

Are there other signs of ADHD besides the ones traditionally used
to establish the diagnosis?
ADHD can show up in children in many ways besides
those defined by established criteria in DSM-IV-TR.
Social-skill issues may be the presenting symptoms at
home and at school. Children may display isolated
aggressive behavior in preschool and early elementary
school, because of their impulsivity and poor attention
to verbal and visual cues. Because their disruptive
behavior often results in conflicts with peers, siblings,

and authority figures, such children stand out from their
classmates. Consequently, they tend to be rejected by
their peers. Children with ADHD may also be quite
messy and disorganized. Parents frequently describe
bedrooms in complete disarray, backpacks with papers
falling out, and poor eating habits. General academic
difficulties are also common. Children forget their assignments,
do not appear to be listening in class, and get
poor grades. In addition, they may have what are usually
called executive functioning problems: difficulties
with planning, starting tasks, shifting from one activity
to another, controlling responses, and staying interested
and motivated.

Do ADHD symptoms in late adolescence
put my child at risk for other kinds of problems?
The persistence of ADHD symptoms into adolescence
is associated with more academic, behavioral, and social
problems. Research indicates that adults with continuing
symptoms complete less formal schooling, are employed
at the usual rates but have lower-status jobs, and have
higher rates of personality disorders. The frequency of
substance abuse is higher among adolescents and young
adults with continuing ADHD. Coexisting conduct and
antisocial personality disorders further increase the risk
of substance abuse.

Recent research comparing children who outgrow
ADHD to those who remain symptomatic suggests that
those with persisting ADHD are more likely to develop
other associated illnesses (e.g., conduct and oppositional
disorders), which can become increasingly prominent
and problematic for these adolescents and young adults.
The risk-taking and rule-breaking behavior can also
significantly worsen parent–child conflicts.


Among children whose symptoms decrease during adolescence,
the outcome is similar to that of non-ADHD
individuals regarding occupational achievement, social
functioning, and drug and alcohol use, although not
academic achievement. Academic issues may remain an
affected area even if ADHD disappears.
Read More: What Are ADHD Symptoms?

What other environmental factors may cause ADHD?

Although environmental factors are most certainly not
the main elements leading to ADHD, evidence suggests
that exposures to various agents, such as drugs, chemicals,
or illnesses, may increase the risk of ADHD. For example,
iron-deficiency anemia and thyroid disorders can cause problems with attention span. Exposure to such substances as lead and mercury may also increase the chances of a child having ADHD.

Can a significant head injury or a minor
concussion cause ADHD?
Behavior problems from significant traumatic brain injury
include irritability, fatigue, impulsiveness, decreased anger
control, disinhibition, decreased motivation, decreased
frustration tolerance, decreased initiative, aggressiveness,
decreased attention, and hypo- or hyperactivity. This
is due at least in part to the fact that a closed-head injury
is likely to damage the frontal lobes of the brain. A
physician must carefully and indefinitely monitor the
classroom attention of a child who has sustained a significant
head injury. In contrast, concussions, which are
associated with only a brief loss of consciousness, are considered very minor head injuries. Nonetheless, children may have trouble concentrating and focusing for several weeks after a concussion. The effects are transient, but can temporarily affect school performance. Paying attention to the problem will minimize it.

Are children born prematurely at
increased risk for ADHD?
The frequency of ADHD in children born prematurely is fairly high. One study compared children who had
been born prematurely with children who were from the  same social class but had been born at full-term. When the children were evaluated at age 7 years, approximately 20% of those in the premature group had ADHD as compared to about 10% of the other group.Many of the premature children who had ADHD also had additional cognitive, neurological, or academic disabilities (e.g., dyslexia and developmental language disorders).

The rapid advances in medical technology have greatly increased the number of children who survive premature birth. However, as more premature babies survive, there is growing evidence that suggests that there are long term repercussions: many of these children—especially the very small ones—develop major neurological problems.

These children appear to be at special risk for ADHD because their frontostriatal circuitry is particularly vulnerable to injury owing to its immaturity at the time of birth. It is wise to carefully monitor children who are
born premature.

My child with iron-deficiency anemia is hyperactive 
rather than tired. Is that common?
Anemia, although commonly thought to decrease energy, can be a cause of inattention and hyperactivity during early childhood. Pediatricians routinely monitor for anemia, which is most often caused by iron deficiency. Iron replacement corrects both the anemia and the inattention and hyperactivity fairly quickly.

Could the many ear infections my child
had as a toddler be the cause of his ADHD?
Some studies, although not all, have found that children with a history of frequent bilateral ear infections had lower language and speech scores, lower reading scores, and more behavior and attention problems during elementary school. Investigators have suggested that children who suffer from intermittent hearing impairments from ear infections do not get enough “practice” in paying attention.

This does not mean that your child will have problems in these areas if he has frequent ear infections, but parents and teachers do need to be vigilant about this problem. It is very unlikely that ADHD is caused by ear infections.
Read More: What other environmental factors may cause ADHD?

What is attention deficit hyperactivity disorder (ADHD)?

Attention deficit hyperactivity disorder (ADHD) is a
disorder in which a child displays hyperactive, impulsive, and/or inattentive behavior that is age-inappropriate.
ADHD is a result of an atypical chemical balance in
the brain, which means that ADHD is a physical problem, not an emotional problem. Outside factors, such as poor parenting, a chaotic home situation, divorce, or school stresses may affect how the symptoms come to light, but they do not cause ADHD. In order to diagnose ADHD (according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision [DSM-IV-TR]), problems of inattention and/or hyperactivity and impulsivity must interfere with a child’s functioning in at least two settings (home, school, or social situations). In addition, the guidelines state that at least some symptoms must have been present before the age of 7 years.

How common is ADHD?
ADHD is quite common; it is conservatively estimated
to affect 3% to 5% of school-age children. Some reports
suggest that as many as 4% to 8% or even an amazing
10% to 18% of children have ADHD. Thus, somewhere
between 2 and 13 million American children
have ADHD. Put another way, on the average, at least
one child in every classroom has ADHD. ADHD
results in millions of physician visits per year.

Approximately 60% of children with ADHD have
symptoms that persist into adulthood. This means that
close to 8 million adults (about 4% of the U.S. adult
population) have ADHD. However, as ADHD is a
behavioral disorder still lacking a specific biological

marker, estimates of its frequency can be affected by a
number of factors.

The method for making the diagnosis most certainly
affects the estimated frequency. The current DSM-IV-TR
standards, which allow both hyperactive–impulsive and
inattentive subtypes, have resulted in higher rates of
diagnosis than previous DSM standards, which placed a
higher emphasis on hyperactivity as a diagnostic criterion.
In other words, the frequency of the diagnosis
increases when hyperactivity is not regarded as a necessary
characteristic for ADHD diagnosis. The looser the
requirements are, the greater the number of individuals
included under the diagnostic umbrella.

The estimated frequency of ADHD also depends on
who provides the information to make the diagnosis:
parent, teacher, child, or physician. All have their own
agendas to report. Teachers are seeing children through
the lens of the classroom, where there are specific academic
and behavioral expectations. In a class full of
children, disruption by a single student can have a ripple
effect. On the other hand, in a large class full of
children, teachers may not notice the quietly inattentive
child. Children may be less aware of their own
symptoms. Adolescents, in particular, are notorious for
underreporting and minimizing their symptoms. Parents
view their children’s behavior from the perspective
of day-in, day-out living. Their perspective is intensive
as well as long-term. On the one hand, they may minimize
symptoms that they have been living with for
years. On the other hand, the behavior seen under the
intensive lens of daily living may make them keenly
aware of things that go unnoticed by others. Physicians
see children in a rather artificial setting, where
the child is the focus of attention and may be on his or

her best behavior. Conversely, some children are stressed
by a visit to the doctor and will immediately demonstrate
ADHD-like signs by wandering around the office, touching
and picking up everything in sight.

The problem of varying perspectives is highlighted in
one study that asked parents, teachers, and physicians
to rate children with school problems as having or not
having ADHD. Results indicated that approximately
10% were rated a unanimous “yes” and 30% a unanimous
“no.” However, parents, teachers, and physicians
disagreed on the diagnosis of almost two-thirds of the
children.

Studies using quantitative questionnaires to assess the
level of agreement between parents, teachers, and children
demonstrate more consistency among raters, but
the specific questionnaire used affects the level of agreement.
Some of the shorter questionnaires tend to diagnose
ADHD less frequently because they emphasize
hyperactivity and, subsequently, miss the inattentive
children. Longer questionnaires, which consider multiple
situations in which attention is required, yield greater
agreement among raters and are probably more reliable
diagnostic tools.

The child’s age at evaluation also makes a difference.
Younger children tend to have more classic symptoms
and more hyperactivity. Thus, the diagnosis is more
likely to be made in these younger children than in
older inattentive, nonhyperactive children.

ADHD seems to occur with differing frequency in
different cultures. For example, ADHD appears to be
more common in the United States than in Britain. A
large British national study found the prevalence of

hyperkinetic disorder (the British term for hyperactivity)
to be only 1.4%. In Japan, a study that based diagnosis
on an older version of the DSM (which places a
greater emphasis on hyperactivity for diagnosis) determined
that 8% of children in the general population
met the standards for ADHD. The frequency of
ADHD in two South American countries, Colombia
and Venezuela, ranged from 7% to 11%. Studies coming
out of Germany suggest a frequency of approximately
16%. The differences could be a reflection of
different thresholds for diagnosis among different cultures
or different diagnostic criteria (or both). For
example, in Britain, hyperactivity appears to be a more
important symptom for diagnosis than in the United
States. The variation in frequency could also be a
reflection of differing gene pools in these countries,
with more ADHD genes in one population than in another.
Read More: What is attention deficit hyperactivity disorder (ADHD)?