Understanding ADHD

by Mary Fowler

ADHD is one of the most commonly diagnosed behavioral disorders of childhood. The disorder is estimated to affect between 3 to 7 out of every 100 school-aged children [American Psychiatric Association (APA), 2000]. This makes ADHD a major health concern. The disorder does not affect only children. In many cases, problems continue through adolescence and adulthood.

The core symptoms of ADHD are developmentally inappropriate levels of inattention, hyperactivity, and impulsivity. These problems are persistent and usually cause difficulties in one or more major life areas: home, school, work, or social relationships. Clinicians base their diagnosis on the presence of the core characteristics and the problems they cause.

Not all children and youth have the same type of ADHD. Because the disorder varies among individuals, children with ADHD won't all have the same problems. Some may be hyperactive. Others may be under-active. Some may have great problems with attention. Others may be mildly inattentive but overly impulsive. Still others may have significant problems in all three areas (attention, hyperactivity, and impulsivity). Thus, there are three subtypes of ADHD:

Predominantly Inattentive Type

Predominantly Hyperactive-Impulsive Type

Combined Type (inattention, hyperactivity-impulsivity)

Of course, from time to time, practically every person can be a bit absent-minded, restless, fidgety, or impulsive. So why are these same patterns of behavior considered normal for some people and symptoms of a disorder in others? It's partly a matter of degree. With ADHD, these behaviors occur far more than occasionally. They are the rule and not the exception. ADHD is a very complex, neurobiochemical disorder. Researchers do not know ADHD's exact causes, as is the case with many mental and physical health conditions. Where ADHD is concerned, there are a few individuals who do not believe ADHD really exists. As researchers continue to learn more about ADHD, this controversy will be put to rest. Meanwhile, scientists are making great strides in unlocking the mysteries of the brain. Recent technological advances in brain study are providing strong clues as to both the presence of ADHD and its causes. In people with the disorder, these studies show that certain brain areas have less activity and blood flow and that certain brain structures are slightly smaller. These differences in brain activity and structure are mainly evident in the prefrontal cortex, the basal ganglia, and the cerebellum (Castellanos & Swanson, 2002). These areas are known to help us inhibit behavior, sustain attention, and control mood.

There is also strong evidence to suggest that certain chemicals in the brain-called neurotransmitters-play a large role in ADHD-type behaviors. Neurotransmitters help brain cells communicate with each other. The neurotransmitter that seems to be most involved with ADHD is called dopamine. Dopamine is widely used throughout the brain. Scientists have discovered a genetic basis for part of the dopamine problem that exists in some individuals with ADHD. Scientists also think that the neurotransmitter called norepinephrine is involved to some extent. Other neurotransmitters are being studied as well (Castellanos & Swanson, 2002).

When neurotransmitters don't work the way they are supposed to, brain systems function inefficiently. Problems result. With ADHD, these are manifested to the world as inattention, hyperactivity, impulsivity, and related behaviors.

Children with ADHD are often blamed for their behavior. However, it's not a matter of their choosing not to behave. It's a matter of "can't behave without the right help." ADHD interferes with a person's ability to behave appropriately.

And speaking of blame-parents and teachers do not cause ADHD. Still, there are many things that both parents and teachers can do to help a child or teen manage his or her ADHD-related difficulties. Before we look at what needs to be done, however, let us look at what ADHD is and how it is diagnosed.

Reprinted from National Information Center for Children and Youth with Disabilities (NICHCY) Briefing Paper, Revised Edition, April 2002. Contact NICHCY at P.O. Box 1492, Washington, DC 20013-1492; phone: 800/695-0285 or 202/884-8200 (Voice/TT)