ADHD is the most commonly studied and diagnosed psychiatric disorder in children, affecting about 3% to 5% of children globally and diagnosed in about 2% to 16% of school aged children. It is a chronic disorder with 30% to 50% of those individuals diagnosed in childhood continuing to have symptoms into adulthood. Adolescents and adults with ADHD tend to develop coping mechanisms to compensate for some or all of their impairments. 4.7 percent of American adults are estimated to live with ADHD.

ADHD is diagnosed two to four times as frequently in boys as in girls, though studies suggest this discrepancy may be due to subjective bias of referring teachers. ADHD management usually involves some combination of medications, behavior modifications, lifestyle changes, and counseling. Its symptoms can be difficult to differentiate from other disorders, increasing the likelihood that the diagnosis of ADHD will be missed. Additionally, most clinicians have not received formal training in the assessment and treatment of ADHD, particularly in adult patients.

ADHD and its diagnosis and treatment have been considered controversial since the 1970s. The controversies have involved clinicians, teachers, policymakers, parents and the media. Topics include the actuality of the disorder, its causes, and the use of stimulant medications in its treatment. Most healthcare providers accept that ADHD is a genuine disorder with debate in the scientific community centering mainly around how it is diagnosed and treated. The American Medical Association concluded in 1998 that the diagnostic criteria for ADHD are based on extensive research and, if applied appropriately, lead to the diagnosis with high reliability.

Classification

ADHD syndrome may be seen as one or more continuous traits found normally throughout the general population. ADHD is a developmental disorder in which certain traits such as impulse control lag in development. Using magnetic resonance imaging of the prefrontal cortex, this developmental lag has been estimated to range from 3 to 5 years. These delays are considered to cause impairment. A diagnosis of ADHD does not, however, imply a neurological disease.

ADHD is classified as a disruptive behavior disorder along with oppositional defiant disorder, conduct disorder and antisocial disorder.

Subtypes

ADHD has three subtypes:

Predominantly hyperactive-impulsive

• Most symptoms (six or more) are in the hyperactivity-impulsivity categories.
  

• Fewer than six symptoms of inattention are present, although inattention may still be present to some degree.
  
  

Predominantly Inattentive

• The majority of symptoms (six or more) are in the inattention category and fewer than six symptoms of hyperactivity-impulsivity are present, although hyperactivity-impulsivity may still be present to some degree.
  

• Children with this subtype are less likely to act out or have difficulties getting along with other children. They may sit quietly, but they are not paying attention to what they are doing. Therefore, the child may be overlooked, and parents and teachers may not notice symptoms of ADHD.

• Combined hyperactive-impulsive and inattentive
  

• Six or more symptoms of inattention and six or more symptoms of hyperactivity-impulsivity are present.
  
  
• Most children with ADHD have the combined type.
  
  
  

Childhood ADHD

Attention-deficit hyperactivity disorder or ADHD is a common childhood condition that can be treated. ADHD may affect certain areas of the brain that allow problem solving, planning ahead, understanding others’ actions, and impulse control.

The American Academy of Child Adolescent Psychiatry (AACAP) considers it necessary that the following be present before attaching the label of ADHD to a child:

• The behaviors must appear before age 7.
  
  
• They must continue for at least six months.
  
  
• The symptoms must also create a real handicap in at least two of the following areas of the child’s life:
  
  
• in the classroom,
  
  
• on the playground,
  
  
• at home,
  
  
• in the community, or
  
  
• in social settings.
  
  

If a child seems too active on the playground but not elsewhere, the problem might not be ADHD. It might also not be ADHD if the behaviors occur in the classroom but nowhere else. A child who shows some symptoms would not be diagnosed with ADHD if his or her schoolwork or friendships are not impaired by the behaviors.

Even if a child’s behavior seems like ADHD, it might not actually be ADHD; careful attention to the process of differential diagnosis is mandatory. Many other conditions and situations can trigger behavior that resembles ADHD. For example, a child might show ADHD symptoms when experiencing:

• A death or divorce in the family, a parent’s job loss, or other sudden change

• Undetected seizures

• An ear infection that causes temporary hearing problems

• Problems with schoolwork caused by a learning disability

• Anxiety or depression

• Insufficient or poor quality sleep

• Child abuse
  
  
  

ADHD-Associated Insomnia in Children

Children and teens with ADHD can experience varying levels of sleep difficulties, which can include falling asleep, staying asleep, or sleeping soundly without tossing and turning (this is also categorized as ADHD-Associated Insomnia). A child who has been getting insufficient sleep may begin to experience behavioral problems with hyperactivity, aggressiveness, and their attention span may worsen. Moodiness can also be linked to a lack of sleep as tired children may be irritable, anxious or depressed. Over time, a child/teen’s health can worsen because trouble sleeping can limit the body’s ability to fight off colds, the flu, and other infectious diseases. Children may begin to struggle with problem-solving and their memory can suffer as well.

Symptoms

Inattention, hyperactivity, and impulsivity are the key behaviors of ADHD. The symptoms of ADHD are especially difficult to define because it is hard to draw the line at where normal levels of inattention, hyperactivity, and impulsivity end and clinically significant levels requiring intervention begin. To be diagnosed with ADHD, symptoms must be observed in two different settings for six months or more and to a degree that is greater than other children of the same age.

The symptom categories of ADHD in children yield three potential classifications of ADHD—predominantly inattentive type, predominantly hyperactive-impulsive type, or combined type if criteria for both subtypes are met:

Predominantly inattentive type symptoms may include:

• Be easily distracted, miss details, forget things, and frequently switch from one activity to another

• Have difficulty focusing on one thing

• Become bored with a task after only a few minutes, unless doing something enjoyable

• Have difficulty focusing attention on organizing and completing a task or learning something new

• Have trouble completing or turning in homework assignments, often losing things (e.g., pencils, toys, assignments) needed to complete tasks or activities

• Not seem to listen when spoken to

• Daydream, become easily confused, and move slowly

• Have difficulty processing information as quickly and accurately as others

• Struggle to follow instructions.
  
  

Predominantly hyperactive-impulsive type symptoms may include:

• Fidget and squirm in their seats

• Talk nonstop

• Dash around, touching or playing with anything and everything in sight

• Have trouble sitting still during dinner, school, and story time

• Be constantly in motion

• Have difficulty doing quiet tasks or activities.
  
  

and also these manifestations primarily of impulsivity:

• Be very impatient

• Blurt out inappropriate comments, show their emotions without restraint, and act without regard for consequences

• Have difficulty waiting for things they want or waiting their turns in games
  
  

Most people exhibit some of these behaviors, but not to the degree where such behaviors significantly interfere with a person's work, relationships, or studies. The core impairments are consistent even in different cultural contexts.

Symptoms may persist into adulthood for up to half of children diagnosed with ADHD. Estimating this is difficult as there are no official diagnostic criteria for ADHD in adults. ADHD in adults remains a clinical diagnosis. The signs and symptoms may differ from those during childhood and adolescence due to the adaptive processes and avoidance mechanisms learned during the process of socialisation.

A 2009 study found that children with ADHD move around a lot because it helps them stay alert enough to complete challenging tasks.

Comorbidities

ADHD may accompany other disorders such as anxiety or depression. Such combinations can greatly complicate diagnosis and treatment. Academic studies and research in private practice suggest that depression in ADHD appears to be increasingly prevalent in children as they get older, with a higher rate of increase in girls than in boys, and to vary in prevalence with the subtype of ADHD. Where a mood disorder complicates ADHD it would be prudent to treat the mood disorder first, but parents of children who have ADHD often wish to have the ADHD treated first, because the response to treatment is quicker.

Inattention and "hyperactive" behavior are not the only problems in children with ADHD. ADHD exists alone in only about 1/3 of the children diagnosed with it. Many co-existing conditions require other courses of treatment and should be diagnosed separately instead of being grouped in the ADHD diagnosis. Some of the associated conditions are:

• Oppositional defiant disorder (35%) and conduct disorder (26%) which both are characterized by antisocial behaviors such as stubbornness, aggression, frequent temper tantrums, deceitfulness, lying, or stealing, inevitably linking these comorbid disorders with antisocial personality disorder (ASPD); about half of those with hyperactivity and ODD or CD develop ASPD in adulthood.

• Borderline personality disorder, which was according to a study on 120 female psychiatric patients diagnosed and treated for BPD associated with ADHD in 70% of those cases.

• Primary disorder of vigilance, which is characterized by poor attention and concentration, as well as difficulties staying awake. These children tend to fidget, yawn and stretch and appear to be hyperactive in order to remain alert and active.

• Mood disorders. Boys diagnosed with the combined subtype have been shown likely to suffer from a mood disorder.

• Bipolar disorder. As many as 25% of children with ADHD have bipolar disorder. Children with this combination may demonstrate more aggression and behavioral problems than those with ADHD alone.

• Anxiety disorder, which has been found to be common in girls diagnosed with the inattentive subtype of ADHD.

• Obsessive-compulsive disorder. OCD is believed to share a genetic component with ADHD and shares many of its characteristics.