Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood disorders and can continue through adolescence and adulthood. Symptoms include difficulty staying focused and paying attention, difficulty controlling behavior, and hyperactivity (over-activity).
ADHD has three subtypes:
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.
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 that he or she has ADHD.
Combined hyperactive-impulsive and inattentive
Six or more symptoms of inattention and six or more symptoms of hyperactivity-impulsivity are present.
Most children have the combined type of ADHD.
Scientists are not sure what causes ADHD, although many studies suggest that genes play a large role. Like many other illnesses, ADHD probably results from a combination of factors. In addition to genetics, researchers are looking at possible environmental factors, and are studying how brain injuries, nutrition, and the social environment might contribute to ADHD.
Genes. Results from several international studies of twins show that ADHD often runs in families. Researchers are looking at several genes that may make people more likely to develop the disorder. Knowing the genes involved may one day help researchers prevent the disorder before symptoms develop. Learning about specific genes could also lead to better treatments.
Children with ADHD who carry a particular version of a certain gene have thinner brain tissue in the areas of the brain associated with attention. This NIMH research showed that the difference was not permanent, however, and as children with this gene grew up, the brain developed to a normal level of thickness. Their ADHD symptoms also improved.
Environmental factors. Studies suggest a potential link between cigarette smoking and alcohol use during pregnancy and ADHD in children. In addition, preschoolers who are exposed to high levels of lead, which can sometimes be found in plumbing fixtures or paint in old buildings, may have a higher risk of developing ADHD.
Brain injuries. Children who have suffered a brain injury may show some behaviors similar to those of ADHD. However, only a small percentage of children with ADHD have suffered a traumatic brain injury.
Sugar. The idea that refined sugar causes ADHD or makes symptoms worse is popular, but more research discounts this theory than supports it. In one study, researchers gave children foods containing either sugar or a sugar substitute every other day. The children who received sugar showed no different behavior or learning capabilities than those who received the sugar substitute. Another study in which children were given higher than average amounts of sugar or sugar substitutes showed similar results.
In another study, children who were considered sugar-sensitive by their mothers were given the sugar substitute aspartame, also known as Nutrasweet. Although all the children got aspartame, half their mothers were told their children were given sugar, and the other half were told their children were given aspartame. The mothers who thought their children had gotten sugar rated them as more hyperactive than the other children and were more critical of their behavior, compared to mothers who thought their children received aspartame.
Food additives. Recent British research indicates a possible link between consumption of certain food additives like artificial colors or preservatives, and an increase in activity. Research is under way to confirm the findings and to learn more about how food additives may affect hyperactivity.
Signs & Symptoms
Inattention, hyperactivity, and impulsivity are the key behaviors of ADHD. It is normal for all children to be inattentive, hyperactive, or impulsive sometimes, but for children with ADHD, these behaviors are more severe and occur more often. To be diagnosed with the disorder, a child must have symptoms for 6 or more months and to a degree that is greater than other children of the same age.
Children who have symptoms of inattention may:
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 they are 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.
Children who have symptoms of hyperactivity may:
Fidget and squirm in their seats
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.
Children who have symptoms of impulsivity may:
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
Often interrupt conversations or others' activities.
ADHD Can Be Mistaken for Other Problems
Parents and teachers can miss the fact that children with symptoms of inattention have the disorder because they are often quiet and less likely to act out. They may sit quietly, seeming to work, but they are often not paying attention to what they are doing. They may get along well with other children, compared with those with the other subtypes, who tend to have social problems. But children with the inattentive kind of ADHD are not the only ones whose disorders can be missed. For example, adults may think that children with the hyperactive and impulsive subtypes just have emotional or disciplinary problems.
Who Is At Risk?
ADHD is one of the most common childhood disorders and can continue through adolescence and into adulthood. The average age of onset is 7 years old.
ADHD affects about 4.1% American adults age 18 years and older in a given year. The disorder affects 9.0% of American children age 13 to 18 years. Boys are four times at risk than girls.
Studies show that the number of children being diagnosed with ADHD is increasing, but it is unclear why.
Children mature at different rates and have different personalities, temperaments, and energy levels. Most children get distracted, act impulsively, and struggle to concentrate at one time or another. Sometimes, these normal factors may be mistaken for ADHD. ADHD symptoms usually appear early in life, often between the ages of 3 and 6, and because symptoms vary from person to person, the disorder can be hard to diagnose. Parents may first notice that their child loses interest in things sooner than other children, or seems constantly "out of control." Often, teachers notice the symptoms first, when a child has trouble following rules, or frequently "spaces out" in the classroom or on the playground.
No single test can diagnose a child as having ADHD. Instead, a licensed health professional needs to gather information about the child, and his or her behavior and environment. A family may want to first talk with the child's pediatrician. Some pediatricians can assess the child themselves, but many will refer the family to a mental health specialist with experience in childhood mental disorders such as ADHD. The pediatrician or mental health specialist will first try to rule out other possibilities for the symptoms. For example, certain situations, events, or health conditions may cause temporary behaviors in a child that seem like ADHD.
Between them, the referring pediatrician and specialist will determine if a child:
Is experiencing undetected seizures that could be associated with other medical conditions
Has a middle ear infection that is causing hearing problems
Has any undetected hearing or vision problems
Has any medical problems that affect thinking and behavior
Has any learning disabilities
Has anxiety or depression, or other psychiatric problems that might cause ADHD-like symptoms
Has been affected by a significant and sudden change, such as the death of a family member, a divorce, or parent's job loss.
A specialist will also check school and medical records for clues, to see if the child's home or school settings appear unusually stressful or disrupted, and gather information from the child's parents and teachers. Coaches, babysitters, and other adults who know the child well also may be consulted.
The specialist also will ask:
Are the behaviors excessive and long-term, and do they affect all aspects of the child's life?
Do they happen more often in this child compared with the child's peers?
Are the behaviors a continuous problem or a response to a temporary situation?
Do the behaviors occur in several settings or only in one place, such as the playground, classroom, or home?
The specialist pays close attention to the child's behavior during different situations. Some situations are highly structured, some have less structure. Others would require the child to keep paying attention. Most children with ADHD are better able to control their behaviors in situations where they are getting individual attention and when they are free to focus on enjoyable activities. These types of situations are less important in the assessment. A child also may be evaluated to see how he or she acts in social situations, and may be given tests of intellectual ability and academic achievement to see if he or she has a learning disability.
Finally, if after gathering all this information the child meets the criteria for ADHD, he or she will be diagnosed with the disorder.
Some children with ADHD also have other illnesses or conditions. For example, they may have one or more of the following:
A learning disability. A child in preschool with a learning disability may have difficulty understanding certain sounds or words or have problems expressing himself or herself in words. A school-aged child may struggle with reading, spelling, writing, and math.
Oppositional defiant disorder. Kids with this condition, in which a child is overly stubborn or rebellious, often argue with adults and refuse to obey rules.
Conduct disorder. This condition includes behaviors in which the child may lie, steal, fight, or bully others. He or she may destroy property, break into homes, or carry or use weapons. These children or teens are also at a higher risk of using illegal substances. Kids with conduct disorder are at risk of getting into trouble at school or with the police.
Anxiety and depression. Treating ADHD may help to decrease anxiety or some forms of depression.
Bipolar disorder. Some children with ADHD may also have this condition in which extreme mood swings go from mania (an extremely high elevated mood) to depression in short periods of time.
Tourette syndrome. Very few children have this brain disorder, but among those who do, many also have ADHD. Some people with Tourette syndrome have nervous tics and repetitive mannerisms, such as eye blinks, facial twitches, or grimacing. Others clear their throats, snort, or sniff frequently, or bark out words inappropriately. These behaviors can be controlled with medication.
ADHD also may coexist with a sleep disorder, bed-wetting, substance abuse, or other disorders or illnesses.
Recognizing ADHD symptoms and seeking help early will lead to better outcomes for both affected children and their families.
How is ADHD diagnosed in adults?
Like children, adults who suspect they have ADHD should be evaluated by a licensed mental health professional. But the professional may need to consider a wider range of symptoms when assessing adults for ADHD because their symptoms tend to be more varied and possibly not as clear-cut as symptoms seen in children.
To be diagnosed with the condition, an adult must have ADHD symptoms that began in childhood and continued throughout adulthood. Health professionals use certain rating scales to determine if an adult meets the diagnostic criteria for ADHD. The mental health professional also will look at the person's history of childhood behavior and school experiences, and will interview spouses or partners, parents, close friends, and other associates. The person will also undergo a physical exam and various psychological tests.
For some adults, a diagnosis of ADHD can bring a sense of relief. Adults who have had the disorder since childhood, but who have not been diagnosed, may have developed negative feelings about themselves over the years. Receiving a diagnosis allows them to understand the reasons for their problems, and treatment will allow them to deal with their problems more effectively.
Currently available treatments focus on reducing the symptoms of ADHD and improving functioning. Treatments include medication, various types of psychotherapy, education or training, or a combination of treatments.
Treatments can relieve many of the disorder's symptoms, but there is no cure. With treatment, most people with ADHD can be successful in school and lead productive lives. Researchers are developing more effective treatments and interventions, and using new tools such as brain imaging, to better understand ADHD and to find more effective ways to treat and prevent it.
The most common type of medication used for treating ADHD is called a "stimulant." Although it may seem unusual to treat ADHD with a medication considered a stimulant, it actually has a calming effect on children with ADHD. Many types of stimulant medications are available. A few other ADHD medications are non-stimulants and work differently than stimulants. For many children, ADHD medications reduce hyperactivity and impulsivity and improve their ability to focus, work, and learn. Medication also may improve physical coordination.
However, a one-size-fits-all approach does not apply for all children with ADHD. What works for one child might not work for another. One child might have side effects with a certain medication, while another child may not. Sometimes several different medications or dosages must be tried before finding one that works for a particular child. Any child taking medications must be monitored closely and carefully by caregivers and doctors.
Stimulant medications come in different forms, such as a pill, capsule, liquid, or skin patch. Some medications also come in short-acting, long-acting, or extended release varieties. In each of these varieties, the active ingredient is the same, but it is released differently in the body. Long-acting or extended release forms often allow a child to take the medication just once a day before school, so they don't have to make a daily trip to the school nurse for another dose. Parents and doctors should decide together which medication is best for the child and whether the child needs medication only for school hours or for evenings and weekends, too.
A list of medications and the approved age for use follows. ADHD can be diagnosed and medications prescribed by M.D.s (usually a psychiatrist) and in some states also by clinical psychologists, psychiatric nurse practitioners, and advanced psychiatric nurse specialists.