Attention Disorder Hyperactivity Disorder (ADHD) affects between 1.5 and 3.5 million school-age children in the U.S., or an estimated 5% of all boys and 2% of all girls. Why ADHD affects more boys than girls is a mystery at this point. Up to 60% of these children will continue to have symptoms into adulthood. According to the National Institutes of Health, more than a million children take prescription medicines to control hyperactive behavior. The estimated cost to schools is about 3 billion dollars.

If you had ADHD, you would have had trouble reading that first paragraph without getting distracted. You would have thought of other things to do. You would have looked around the room, focusing on things other than the computer screen. You might have even gotten up and wandered off. No wonder children with ADHD have trouble being in school and focusing on school work.

Signs to Look For

Almost all people at some point exhibit some of the symptoms of ADHD. We all get distracted at times; we all have had trouble finishing work or tasks. However, children with ADHD are, in general, less able to care for themselves, less able to recognize appropriate social behavior, and less able to communicate than non-ADHD children of the same age. The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) published by the American Psychiatric Association has a very specific listing of behaviors that must be observed before a diagnosis of ADHD is made.

There are many reasons other than ADHD why children may have these behaviors. Infections, learning disabilities, or educational issues may result in symptoms similar to ADHD.

Some days, for some reason, these symptoms may be absent, leading others to think that the person with ADHD can control the behaviors. A definite diagnosis is difficult because there are no tests that consistently detect ADHD. A physician can only observe behaviors and guess whether the child has ADHD. Many children have trouble concentrating, or may not be in a mood to cooperate on the day they see the doctor. This could lead to an incorrect diagnosis. ADHD must be diagnosed by a health care professional who specializes in these types of disorders in cooperation with parents and teachers.

Examining the Cause

There is no clear-cut cause of ADHD. It appears that certain receptors in the brain which normally respond to the neurotransmitter called dopamine are not working properly. Most likely, dopamine is not being produced at normal levels in the brain. Recent work in adults points to a defect in an enzyme called dopa decarboxylase which helps make dopamine. This defect in dopamine production occurs in the anterior frontal cortex, an area associated with cognitive processes such as focusing and attention.

There is also evidence that children who were born weighing less than 1500 grams (3.3 pounds) or who had birth complications may be more prone to ADHD. Additionally, studies have linked resistance to thyroid hormones to hyperactivity and lack of impulse control, but it is unclear how this impacts ADHD.

Other factors which are being investigated to see what role they may play in ADHD are exposure during preganancy to:

• Toxins (such as lead)

• Drugs (such as alcohol or cocaine)

According to the National Institutes on Health, ADHD is not usually caused by:

• Too much TV

• Food allergies

• Excess sugar

• Poor home life

• Poor schools

There is increasing evidence that ADHD is an inherited condition. If one identical twin has symptoms of ADHD, the other twin has a 75-91% chance of sharing the same trait. Children who have ADHD are likely to have one close relative who also has ADHD. One-third of all fathers who had ADHD when they were young have children who have ADHD.

Adoption studies provide more evidence of a genetic link to ADHD: biological relatives of children with ADHD have a higher chance of having ADHD than adoptive relatives of children with ADHD.

Structural Signs

Studies in the past few years have shown that boys with ADHD tend to have brains that are more symmetrical in shape. Three structures in the ADHD boys' brains were smaller than in non-ADHD boys of the same age: prefrontal cortex, caudate nucleus, and the globus pallidus. The prefrontal cortex is thought to be the brain's "command center;" the other two parts translate the commands into action.

Now there is evidence that not only are some of the structures slightly different, but the brain may use these areas differently. By taking a brain scan, researchers have noticed that boys with ADHD have an abnormal increase of activity in two structures: the frontal lobe and striatal areas below it. These areas work in part to control voluntary action. So the ADHD boys were working harder to control their impulses than non-ADHD boys. Once given Ritalin, this abnormal activity quieted down. This effect was not seen in the non-ADHD boys. So Ritalin may act differently on ADHD brains compared to "normal" brains.

Although the brain scan, called functional magnetic resonance imaging (fMRI), is expensive--about $1500--and may not be covered by insurance, it may provide a more accurate way to diagnose ADHD. As science explores more of the mysteries of the brain, ADHD may be thought of more as a disability or disorder, rather than a behavioral problem.

Treatment

Three medications classified as stimulants are used to control the symptoms of ADHD.

These medications can be addictive in teenagers and adults, but they have not been found to be addictive in children. Nine out of 10 children improve on one of these stimulants, so if one does not work, the others are tried. If these medications do not work, some children respond well to antihistamines, usually prescribed for allergies. Clonidine, a drug normally used to treat hypertension, also alleviates some symptoms of ADHD. With any of these medications, adjusting the dosage for each child is vital for treating the symptoms of ADHD.

People who do NOT have ADHD may also respond to stimulants and may find that their attention and ability to focus will improve. This reaction does not mean that they have ADHD. It is not recommended for people without a diagnosis of ADHD to use these drugs. No one knows if stimulants have the long-term effects.

Ritalin is the best known drug used to treat ADHD. It was first used in the 1950s to treat narcolepsy, an illness where people suddenly fall asleep at irregular times. It works by making more dopamine available in the brain by reducing dopamine reuptake. Therefore, dopamine can stay in the synapse for a longer time. Ritalin curbs symptoms such as hyperactivity and other behavioral problems, but it does not improve IQ.

Ritalin is being prescribed at an astonishing rate. Statistics mentioned in a TIME magazine article are telling: Ritalin production in the US has increased more than sevenfold in the past eight years. Ninety-percent of it is consumed by people in the US.

Why have the prescriptions skyrocketed? Part of the reason may be pressure--pressure from teachers for children to behave, pressure from parents for their children to do well in school and to succeed in other pursuits, and pressure from society for children to do more and better, at a younger age.

Ritalin has side effects that include irritability, decreased appetite, inability to sleep, depression, and personality changes. With the increase in information about where dopamine may be deficient, medication could be designed to target those deficient areas instead of increasing dopamine production in the entire brain. This may reduce the side effects associated with Ritalin and other drug medications.

Controversy

Ritalin is one of the most commonly prescribed drugs for children, but there are worries about its long-term effects. There are no studies on children who have taken Ritalin for more than 14 months. Ritalin affects the brain in a way very similar to cocaine, one of the most addictive substances known. Are children who take Ritalin more likely to use illegal drugs in the future? Are they more likely to smoke as adults?

There is reason for this concern. Rats who were exposed to stimulants were more likely to help themselves to cocaine, suggesting that early exposure to some drugs may "prime" a person for future drug use. The data on whether there is a link between Ritalin and later substance abuse are controversial. Some studies show that Ritalin makes people more prone to addiction to certain substances. Other researchers insist that ADHD children are not more likely to use drugs of any type later in life.

Combining Therapies

Prescription medications help control the symptoms of ADHD, but other therapies, such as psychotherapy and behavioral therapy, can also help ADHD children. Many experts now advocate combining drugs with therapy. Other helpful approaches include: creative teaching, visual signs to remind children of the task at hand, constant reinforcement, adding rules and structure to the daily routine, special education, and other techniques used for learning disabled students.

The immediate problem with this is that insurance companies will be more likely to cover the cost of a pill, but may hesitate to cover long-term therapy sessions. Thus, often the treatment for ADHD is focused on the short-term, not on the long-term.

Coping Strategies

The NIH booklet on ADHD lists ways for people with ADHD to cope better at work or school:
 

• When necessary, ask for instructions again--don't guess about what you're supposed to do.

• Break large or complex tasks into smaller jobs. Set deadlines for each tasks and reward yourself when you complete each one.

• Each day make a "to do" list. Use a calendar to keep you on track.

• Work in a quiet area. Do one thing at a time. Give yourself short breaks.

• Create a routine. Do the same things in the same order each day.

• Eat a balanced diet, exercise, and get enough sleep each night.

NIH ADHD Booklet

Watch your Head!

Hospital records indicate that children with ADHD may be more accident prone. And not only that, but the injuries were more severe than in non-ADHD children of the same age and gender. This is one more reason to put on a helmet when riding a bike, skating, rollerblading, or skateboarding.

The Road Ahead

Although scientists have gained much information in the past few years, ADHD is keeping some of its secrets. Why does it affect more boys than girls? Is ADHD "real" or is society simply labeling children who are having difficulties? And how does dopamine fit into this? Is Ritalin the beginning of a drug dependency or an antidote for needing illegal drugs in order to function? Are the abnormalities in a child with ADHD the same as those seen in adults who have ADHD? Much more work still lies ahead.

We wish to thank Dr. Eric H. Chudler, Ph.D. for his persmision to publish this page .

Please visit Dr. Chudler's web site at http://faculty.washington.edu/chudler/neurok.html