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Attention deficit hyperactivity disorder (ADHD): Overview

Created: ; Last Update: September 20, 2018; Next update: 2021.


Attention deficit hyperactivity disorder, ADHD, is a disorder in which children are especially inattentive, impulsive or hyperactive. “Inattentive” refers to children who have difficulties focusing and are easily distracted. Overly “impulsive” children act in a way that is extremely rash, inconsiderate, careless or impatient for their age. “Hyperactive” describes children who are restless or constantly fidgeting – for instance, they may not be able to sit still during school lessons, and might get up and walk around the classroom a lot instead.

Severe ADHD can cause major problems in the child’s life and everyday routine, as well as that of their whole family: Children with ADHD behave differently than expected, so they often cause trouble. They need a lot of attention. Because of their short attention span, they find it difficult to learn. Some of them have abnormal social behavior, anxiety or depression.

The number of children being diagnosed with ADHD has increased in recent years. Some people are wary of this development and doubt that ADHD is really that common. They're worried that a lot of children who are diagnosed with ADHD are simply a little overactive, but otherwise healthy. A wrong diagnosis may lead to unnecessary treatment. Being wrongly labeled as mentally ill may also affect a child’s self-esteem.

But there are children and teenagers who actually have ADHD and aren’t diagnosed with it. This can also have a negative effect, because they may not get treatment that could help them. So it's very important to take the time to look into things so ADHD can be ruled out or diagnosed.


Inattentiveness, impulsive behavior and hyperactivity are generally not unusual for children and teenagers. But this type of behavior is extreme in ADHD, and clearly different to the behavior of other children of the same age.

An inattentive child may have trouble listening at school, be easily distracted and make a lot of careless mistakes. They may also have difficulty staying focused in their free time, and are often forgetful or lose things. An impulsive child might hardly be able to wait his or her turn in school or when playing games. They may push in or interrupt others. Hyperactive children are usually fidgety, and may bounce around on their chair or have trouble being quiet. They're often restless, doing things like running around or climbing up on furniture. Inattentive and impulsive behavior can get worse when children are in situations where there's a lot to take in and process, like at a party or on vacation.

The severity of ADHD and which of the behaviors is more pronounced can vary between boys and girls and from child to child. Some children may be more affected by inattentiveness and often appear to be daydreaming. Other children are especially impulsive and hyperactive. Depending on which of these behaviors is more obvious, children with ADHD can be divided into two groups: primarily inattentive or primarily hyperactive-impulsive. Children who are extremely inattentive, but not hyperactive, are also described as having attention deficit disorder (ADD).

Causes and risk factors

The causes of ADHD aren't fully understood, but it probably can' be attributed to a single factor. Genes play an important role. Research has shown that, in children with ADHD, the chemical messenger dopamine is transported differently between the nerve cells of the brain, especially in the regions that are used for memory and learning. And there are other biological differences that may be involved in the development of ADHD.

Some experts disagree with the view that ADHD is only linked to physical or genetic factors. Instead, they consider changes in our society to be just as important. They believe that ADHD symptoms also result from overstimulation coupled with lack of exercise, modern society’s emphasis on achievement, and changes in a child’s family situation. Hardly any good-quality studies have tested these theories, though.

It’s also not clear what factors might play a role in the risk of developing ADHD. Individual studies have shown that children are at greater risk if their mothers smoked, drank alcohol or consumed other drugs while pregnant. There's also a possible link between ADHD and very low birth weight or other childbirth-related problems like a lack of oxygen at birth. Genetic factors and external circumstances probably both play a role.

Certain foods are sometimes associated with ADHD. Some research does actually suggest that children who often eat foods containing artificial colors and preservatives are more likely to behave abnormally. But nutrition appears to play a very small role at most. If you think it may be a factor, you can test whether changing the child’s diet helps.


Attention deficit hyperactivity disorder is very common. About 5% of children are diagnosed with ADHD in Germany. But one representative study on the prevalence of ADHD in Germany shows that only 1 to 2% of children meet the actual criteria for diagnosis, and that it's twice as common in boys as in girls. This implies that some children are wrongly diagnosed with ADHD. There are also some children who have ADHD and are never diagnosed with it, though. It's not known exactly how often this happens.


ADHD usually first develops in childhood. In adulthood the symptoms are generally much less severe or may have disappeared completely.

More than 50% of children who have ADHD show at least some symptoms as adults. About 15% still fulfill all of the criteria for an ADHD diagnosis when they are adults.

But the symptoms often change as people age. For instance, teenagers and adults with ADHD are usually less hyperactive than they were as children, but often feel restless.


ADHD can have far-reaching effects. Children and teenagers with ADHD have more accidents, hurt themselves more often, and have more problems at school. They tend to have more conflicts with their peers and go against the rules, or behave defiantly and even aggressively. Teenagers with ADHD are more likely to smoke, drink alcohol or use other drugs, which may make other problems worse. They are also more frequently involved in crimes than other people their age who do not have ADHD. Developmental problems may arise too, such as difficulties with language development or reading and writing.

Children with ADHD may also have other emotional problems or disorders, including things like depression or anxiety disorders. Some children with ADHD have a tic disorder as well.

When adults have ADHD, it usually causes problems in relationships or at work. Especially adults who were very hyperactive and impulsive as children are sometimes inconsiderate: Some of them find it difficult to attend to their responsibilities, tell the truth, or respect other people.


It's best to have ADHD diagnosed by specialists who are very familiar with the disorder. These may include doctors, psychiatrists or psychotherapists who specialize in treating children and teenagers.

An in-depth talk and physical examination are important for ruling out other possible causes of the abnormal behavior. Things like sleep problems, problems with vision or hearing, or an overactive thyroid gland might also lead to poor concentration, difficulties at school or hyperactivity.

The talk can also help to rule out other mental disorders as possible causes, and to diagnose any additional medical conditions. Your doctor or therapist may ask you questions like these:

  • Is your child forgetful, easily distracted or unfocused?
  • Does your child frequently climb up on things, disrupt others, or get very angry?
  • Does the behavior occur both at school and at home?
  • How long have you observed this kind of behavior in your child?
  • Does your child’s performance at school suffer as a result, or does your child have difficulty finding friends because of their behavior, and are they unhappy about it?

The diagnosis should be made on the basis of clear criteria, using psychological tests and questionnaires. The child’s teachers or preschool teachers may also be asked to describe the child’s behavior in school or preschool.


Before any treatment is started, the doctor will talk about what ADHD is and how to cope with it. As well as the parents and their child, teachers and preschool teachers may be there, too. It may then turn out that there is no urgent need for treatment. It's important to consider how much of a problem the behavior is for the child and their parents, and whether things like their performance at school are suffering as a result. Paying attention to good sleeping habits can also help.

If a child only has a mild form of ADHD that doesn't affect his or her life too much, it might be enough to complete a parent training and education program on dealing with ADHD. These programs can be taken as a class with an instructor or done on your own using written material.

If a child has moderate or severe ADHD that is causing problems at school and in their social environment, it may be helpful to try interventions at school or have family or behavioral therapy. The type of help that will be most effective will depend on the child’s age, whether they tend to be more inattentive or more hyperactive, and what areas of their life the ADHD has the greatest impact on.

Medication can relieve ADHD symptoms. When making a decision about treatment with medication, various factors play a role. These include the age of the child, the severity of the ADHD, whether psychotherapy or behavioral approaches have been attempted, and how the parents and the child view the pros and cons of treatment with medication. The drug methylphenidate is the most commonly used medication. If methylphenidate doesn't work or can't be used for other reasons, the drugs atomoxetine, dexamfetamine, guanfacine or lisdexamfetamine may be used instead.

Treatment at a psychosomatic or psychiatric hospital for children and teenagers may be a good idea for children who are extremely hyperactive and impulsive and have great difficulty coping in daily life, or can no longer cope at all. Hospital treatment may also be needed if the child has other severe mental disorders too.

Everyday life

Raising a child with ADHD can be very difficult. Severe ADHD is a challenge for the entire family: Parents face a lot of conflicts because their child often has problems at school, with other children and their parents, or within the family. Brothers and sisters are often stressed or feel neglected because their parents have less time for them. The children who have ADHD also suffer as a result of their own behavior: They have difficulties finding friends and often annoy others.

Over time, many parents develop strategies to help them cope with ADHD. Clear rules and routines are often effective. Talking with other parents in a self-help group can help too. It is important to remember that the child’s behavior is not intentional.

In Germany and other countries, it may be possible for the child to go on a retreat with one of their parents (in German: Mutter-/Vater-Kind-Kur) if everyday life becomes too difficult. The aim of this kind of program is to help parents and their children take a step back from their everyday problems and then, together with therapists, find ways to cope better.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.


© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK321129


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