ADHD: An Introduction

by Mary Fowler

Is ADD something new?
References to ADD-type symptoms have been found in the medical literature for almost 100 years. In fact, this syndrome is one of the most widely researched of all childhood disorders.

 

Throughout all these years of research, the children with ADD have not changed. The characteristics of ADD evident 40 years ago are still the same seen today. It is our understanding of ADD that has evolved. The knowledge we have gained through research has, in fact, led to a change in the disorder's name and in the way it is viewed.

 

What is Attention Deficit Disorder?
ADD is officially called Attention-Deficit/Hyperactivity Disorder, or ADHD (American Psychiatric Association, 1994), although most lay people, and even some professionals, still call it ADD (the name given in 1980). The disorder's name has changed as a result of scientific advances and the findings of careful field trials; researchers now have strong evidence to support the position that ADHD is not one specific disorder with different variations. In keeping with this evidence, ADHD is now divided into three subtypes, according to the main features associated with the disorder: inattentiveness, impulsivity, and hyperactivity. The three subtypes are:

  1. ADHD Predominantly Combined Type,
  2. ADHD Predominantly Inattentive Type, and
  3. ADHD Predominantly Hyperactive-Impulsive Type.

These subtypes take into account that some children with ADHD have little or no trouble sitting still or inhibiting behavior, but may be predominantly inattentive and, as a result, have great difficulty getting or staying focused on a task or activity. Others with ADHD may be able to pay attention to a task but lose focus because they may be predominantly hyperactive-impulsive and, thus, have trouble controlling impulse and activity. The most prevalent subtype is the combined type. These children will have significant symptoms of all three characteristics.

 

What Causes ADHD?
ADHD is a neurobiologically-based developmental disability estimated to affect between three to five percent of the school age population (Professional Group for Attention and Related Disorders, 1991). No one knows exactly what causes ADHD. Scientific evidence suggests that the disorder is genetically transmitted in many cases and results from a chemical imbalance or deficiency in certain neurotransmitters, which are chemicals that help the brain regulate behavior. In addition, a landmark study conducted by the National Institute of Mental Health showed that the rate at which the brain uses glucose, its main energy source, is lower in subjects with ADHD than in subjects without ADHD (Zametkin et al., 1990).

 

In short, we do know that ADHD is a neurologically-based medical problem and that parents and teachers do not cause ADHD. Fortunately, there are many things that teachers and parents can do to help a child manage his or her ADHD-related difficulties.

Reprinted from National Information Center for Children and Youth with Disabilities (NICHCY) Briefing Paper, Revised Edition, October 1994. Contact NICHCY at P.O. Box 1492, Washington, DC 20013-1492; phone: 800/695-0285 or 202/884-8200 (Voice/TT); email: nichcy@aed.org