Attention Deficit Hyperactivity Disorder (ADHD)

Attention is the mental process in which a person concentrates awareness on a specific object, issue, or activity and excludes other potential stimuli * in the environment. Attention deficit hyperactivity disorder (ADHD) is a common developmental disorder that affects both children and adults, although it is usually diagnosed in childhood. ADHD affects a person's ability to study, learn, work, play, and even socialize with others. People with ADHD are less able to sit still, plan ahead, organize and finish tasks, and tune in fully to what is going on around them than are people without the disorder.

A Tale of Two Students

Even though Justin and Katie are both seventh-grade students with ADHD, they act quite differently at school. Justin has a very hard time sitting still and staying in his seat. His classmates and teachers think of him as hyper. Justin gets bored easily, so he tends to talk too much and get into trouble. He also bothers the other students, which leads them to get angry at him.

Katie does not wiggle and fidget the way Justin does. But she has similar difficulty keeping her mind on her work and paying attention to the teacher. Katie forgets which assignments she is supposed to do. She finds it tougher than most to keep track of her backpack, books, and school supplies. Sometimes she loses her homework, and sometimes she just forgets to turn it in.

What Is Attention Deficit Hyperactivity Disorder?

Attention deficit hyperactivity disorder (ADHD, also called ADD) is a condition that causes poor attention span, easy distractibility, hyperactivity * , and impulsiveness. People with ADHD may have only one or two of these problems, or they may have all of them. Those with an attention problem have a hard time keeping their mind on any one subject for long. They may get bored with a task after only a few minutes. People who are hyperactive seem to be in constant motion. They may feel restless and squirm or fidget a lot. People who are overly impulsive seem not to think before they speak or act. They may blurt out embarrassing comments without thinking or take dangerous risks. The symptoms usually begin before seven years of age, although they may not be recognized as signs of ADHD until later. The behaviors associated with ADHD can lead to trouble with school, work, or relationships with family, friends, and teachers.

Difficulties caused by ADHD often improve during the late teen years and adulthood. Many adults are left with only a few signs of ADHD, but a few still have the full disorder. People with ADHD do not outgrow the condition. While they often become less hyperactive when they get older, people with ADHD may still have problems with restlessness and a short attention span. By using certain coping strategies, many people with ADHD learn to deal with the condition successfully and can achieve in school and thrive in rewarding careers. Many people are able to find the right kind of job for their strengths and abilities. For example, a person might be better suited for a position that offers variety and constant change rather than one that requires long periods sitting at a desk.

What Causes Attention Deficit Hyperactivity Disorder?

Doctors and researchers are not sure why certain people have ADHD. Theories have focused on various possible causes, such as diet, head injuries, exposure to drugs before birth, and even family and home environment. None of these theories offers a satisfactory explanation for most cases of ADHD.

Researchers interested in learning about possible biological causes of ADHD have looked at how the brains of people with ADHD function compared to the brains of those without ADHD. Neuroscientists, or scientists who study the brain and nervous system, believe that attention is largely a function of the brain's reticular activating (re-TIK-yoo-lur AK-ti-vay-ting) system, or RAS. This system includes a group of nerve fibers located in several parts of the brain, including the thalamus *

Using a special scanning test called a positron emission tomography, or PET, scan, researchers can watch the brain as it works. The test lets them see how much glucose, a type of sugar, is used by the areas of the brain that inhibit impulses and control attention (glucose is the brain's main source of energy). Some studies have found that the areas of the brain that control attention use less glucose in people with ADHD, which means that these areas of the brain appear to be working less hard. Other researchers speculate that ADHD has something to do with differences in the neurotransmitters * that deliver signals to the brain areas that control attention. Some research also suggests that use of alcohol or drugs by the mother during pregnancy can harm development of the baby's brain cells. Such maternal choices may be one cause of ADHD, although it is likely that there are many causes. A person's genetic makeup may be involved. ADHD seems to run in families. Children with ADHD usually have at least one parent, sibling, or other close relative with the disorder. Scientific studies have also found that if one identical twin * has ADHD, the other twin is likely to have it as well.

What Does Not Cause Attention Deficit Hyperactivity Disorder?

Experts used to think that attention problems were caused by slight brain damage or minor head injuries. However, most people with ADHD have no sign of brain damage or any history of head injury. Another theory proposed that overactive behavior was caused by refined sugar and food additives. But scientists found that eating a special diet seemed to help only about 5 percent of children with ADHD, mostly very young children or those with food allergies. It is true that too much caffeine (found in coffee, tea, and some sodas) or some red and yellow dyes can intensify hyperactive behaviors.

How Is Attention Deficit Hyperactivity Disorder Diagnosed?

The symptoms of ADHD are similar to other health problems. For example, depression can lead to trouble paying attention, and anxiety can make it hard to sit still. A learning disability can lead to poor school performance, and small seizures can cause mental lapses. Even an ear infection that leads to on-again-off-again hearing loss can cause behaviors that look like ADHD symptoms. In addition, everyone has trouble staying focused and getting organized at times. For these reasons, ADHD needs to be diagnosed by a trained medical or mental health professional.

Diagnosing ADHD is difficult because symptoms vary, and no single test can determine whether someone has ADHD. In most cases, parents notice that their child is much less attentive or has less control over his or her behavior than other children. The disorder usually is not diagnosed until the child enters school and is expected to follow directions, cooperate with others, and be quiet at certain times.

To make the diagnosis, a psychologist or psychiatrist * looks for patterns of certain behaviors that have lasted for more than six months, and interfere with two or more areas of a person's life, such as school and play, school and home, or home and work. In addition to interviewing the child and family members, the specialist may need to speak with others who know the child well, such as teachers and coaches. Former teachers may be asked to fill out an evaluation. Special tests may be administered to clarify the diagnosis.

Can Food Cause Hyperactivity?

Anyone who drinks too much cola or coffee is likely to have a hard time concentrating because caffeine can overstimulate the brain. At one time, mental health specialists believed that sugar and other food additives actually contributed to ADHD. As a result, parents were encouraged to stop serving children foods containing artificial flavorings, preservatives, and sugars. It was thought that this restricted diet could actually prevent or cure the symptoms of the condition. Later, researchers abandoned this theory.

The behaviors that experts look for fall into three categories: inattention, hyperactivity, and impulsivity. Signs of inattention in a child include the following:

Hyperactivity refers to overly active behavior. Children experiencing hyperactivity might engage in the following:

An impulsive child might engage in the following:

Children with ADHD may have other behavioral disorders as well. These may include oppositional defiant disorder * , depression * , anxiety * , and delays in learning speech and language.

How Is Attention Deficit Hyperactivity Disorder Treated?

Usually, ADHD is first treated with behavioral (be-HAY-vyor-ul) therapy, which involves working with a psychologist or psychotherapist * to learn ways of coping with the condition. The therapist can help people become more aware of their behavior; develop strategies for controlling it; and even help them practice how to deal with situations that caused problems in the past. A person also might find it helpful to participate in a support group with others who have similar difficulties.

Parents and teachers are involved in the treatment plan as well. Parents can learn how to establish more structure for the child; define limits more clearly; and be consistent with discipline, all of which are especially important for a child with ADHD. Teachers can provide predictable routines and structure in the classroom, and try to keep the student away from distractions. Both parents and teachers can establish certain penalties and rewards to help the child make progress with behavior.

If these strategies are not effective enough in controlling the condition on their own, then a psychostimulant (SY-ko-STIM-yoo-lint) medication such as methylphenidate (meth-il-PHEN-uh-date; Ritalin, Concerta, Methylin, Metadate); dextroamphetamine (dex-tro-am-PHET-uh-meen; Dexedrine, Dextrastat); or mixed amphetamine salts (Adderall) might be prescribed. It may seem strange that an inattentive, overly active person would be treated with a stimulant * . These medications work by stimulating certain areas of the brain that make it possible for many people with ADHD to concentrate, behave more consistently, and take part in activities that were impossible before. These drugs may work to control ADHD by increasing the amount and activity of some of the brain chemicals known as neurotransmitters. The behavior and general functioning of 9 out of 10 typical children with ADHD improve when the individuals take one of these drugs. If one stimulant medicine does not help, another can be tried.

When taken as directed by a doctor, stimulant medicines are considered safe. They usually do not make the patients “high” or jittery, but they may cause other unwanted side effects * . Some patients may lose weight, feel less hungry, or grow more slowly. Others may have trouble falling asleep. If such side effects occur, they can often be handled by changing the dose or drug. A doctor needs to track the growth of any patient taking these medicines closely.

Common Drugs to Treat ADHD

Common Drugs to Treat ADHD
Table by PreMediaGlobal. © 2016 Cengage Learning®.

Other medications that may be prescribed include atomoxetine (Strattera), which is a nonstimulant medicine for children, teens, and adults used to treat ADHD. Additional nonstimulant medications used to treat aggression, inattention, and impulsivity include clonidine (Kapvay) and guanfacine (Intuniv). At times a doctor may recommend an antidepressant to help control the symptoms.

Why Is Attention Deficit Hyperactivity Disorder Diagnosed More and More Frequently?

More children than ever before are being diagnosed with ADHD–Predominantly Impulsive Hyperactive Type or ADHD–Predominantly Inattentive Type. In addition, the use of stimulant medications increased dramatically during the 1990s; according to one estimate, production of these medications increased by 700 percent between 1990 and 1997. There is some disagreement over why these patterns occurred. Some people think that greater awareness of the condition led more teachers to suspect problems among their students and more parents to seek help for their children. Others believe that some cases of bad behavior were misdiagnosed as ADHD. Some argue that parents may find it easier to accept that their child has a mental health disorder rather than learn how to deal with unruly behavior or poor school performance due to other reasons. The debate continues, while the medical community agrees that ADHD is a real condition that can have serious consequences if it is not diagnosed and managed appropriately.

Some clinicians question the effectiveness of stimulant medications to treat ADHD, and whether they may be overused. A 2015 Cochrane Review of 185 randomized, controlled studies urged caution in prescribing stimulant medication. The review notes that while the studies did indicate modest improvements in symptoms for those individuals using medication, study results could be questionable as participants may have been able to determine if they were in the medication group, which could in turn affect reported results. In addition, in some studies, reporting of results was incomplete.

What Are Strategies for Living with Attention Deficit Hyperactivity Disorder?

The National Institute for Mental Health, the federal agency for research on mental health disorders, recommends the following strategies for living with ADHD:

A student with attention deficit hyperactivity disorder receives one-on-one instruction with his teacher. The method of teaching students according to their own special way of learning is effective in managing ADHD.

A student with attention deficit hyperactivity disorder receives one-on-one instruction with his teacher. The method of teaching students according to their own special way of learning is effective in managing ADHD.
Monkey Business. Images/

See also Anxiety and Anxiety Disorders: Overview • Depressive Disorders: Overview • Learning Disabilities: Overview • Oppositional Defiant Disorder • Psychopharmacology


Books and Articles

Barkley, Russell A. Attention-Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment. 4th ed. New York: Guilford Press, 2014.

Quinn, Patricia O., and Judith M. Stern. Putting on the Brakes: Understanding and Taking Control of Your ADD or ADHD. 3rd ed. Washington, DC: Magination Press, 2012.


Centers for Disease Control and Prevention. “Attention-Deficit/Hyperactivity Disorder (ADHD).” . (accessed March 5, 2016).


ADDvance. 8607 Cedar St., Silver Spring, MD 20910. Telephone: 301562-8448. Website: (accessed March 5, 2016).

ADD Warehouse. 300 NW 70th Ave., Suite 102, Plantation, FL 33317. Toll-free: 800-233-9273. Website: (accessed March 5, 2016).

Attention Deficit Disorder Association (ADDA). PO Box 7557, Wilmington, DE 19803. Telephone: 800-939-1019. Website: (accessed March 5, 2016).

Children and Adults with Attention-Deficit/Hyperactivity Disorder. 4601 Presidents Dr., Suite 300, Lanham, MD 20706. Telephone: 800-233-4050. Website: (accessed March 6, 2016).

National Institute of Mental Health. 6001 Executive Blvd., Room 6200, MSC 9663, Bethesda, MD 20892-9663. Telephone: 866615-6464. Website: (accessed March 5, 2016).

* stimuli (STIM-yoo-lie) are things in the environment that excite a person to function, become active, or respond. The singular form is stimulus.

* hyperactivity (hy-per-ak-TI-vi-tee) is overly active behavior, which makes it hard for a person to sit still.

* thalamus (THAL-uh-mus) refers to a pair of large egg-shaped areas located in the middle of the brain just under the cerebral cortex. The plural form is thalami.

* neurotransmitters (nur-otrans- MIH-terz) are chemical substances that transmit nerve impulses, or messages, throughout the brain and nervous system and are involved in the control of thought, movement, and other body functions.

* identical twins are twins produced when a single egg from the mother is fertilized and divides to form two separate embryos of the same sex with nearly identical DNA.

* psychiatrist (sy-KY-uh-trist) is a medical doctor who has completed specialized training in the diagnosis and treatment of mental illness. Psychiatrists can diagnose mental illnesses, provide mental health counseling, and prescribe medications.

* oppositional defiant disorder (op-uh-ZIH-shun-ul de-FY-unt dis- OR-der) is a disruptive behavior disorder that can be diagnosed in children as young as preschoolers who demonstrate hostile or aggressive behavior and who refuse to follow rules.

* depression (de-PRESH-un) is a mental state characterized by feelings of sadness, despair, and discouragement.

* anxiety (ang-ZY-e-tee) can be experienced as a troubled feeling, a sense of dread, fear of the future, or distress over a possible threat to a person's physical or mental well-being.

* psychotherapist (sy-ko-THER-apist) is any mental health professional who works with people to help them change thoughts, actions, or relationships that play a part in their emotional or behavioral problems.

* stimulant (STIM-yoo-lunt) is a drug that produces a temporary feeling of alertness, energy, and euphoria.

* side effects are unwanted symptoms that may be caused by vaccines or medications.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)