An ADHD Primer

ADHD, also known as attention deficit/hyperactivity disorder, affects adults as well as children. It tends to run in families, and it's not caused by eating too much sugar.

Medically reviewed by Niya Jones, MD, MPH

Attention deficit hyperactivity disorder (ADHD), also commonly known as attention deficit disorder (ADD), is one of the most common mental illnesses found in children. ADHD is a brain disorder that causes behavioral problems such as a distractibility, excessive energy, disorganization, and forgetfulness. Until recently, doctors thought that ADHD/ADD affected only children, but now know that more than half of youngsters with ADHD remain affected into adulthood.

ADHD/ADD: A New Name

Commonly called ADHD or ADD, this condition was officially renamed attention-deficit/hyperactivity disorder (ADHD) with the publication of the most recent diagnostic guidelines used by the American Psychiatric Association.

“These guidelines divide ADHD into three subtypes,” says Andrew Hertz, MD, assistant clinical professor of pediatrics at Case Western Reserve Medical School in Cleveland, Ohio, and medical director of Suburban Pediatrics in Shaker Heights. “The distinctions are very helpful because all the different the symptoms of ADHD are no longer lumped under a single heading. The pediatrician can choose among the most successful treatments for that particular subtype.”

The subtypes are:

Predominantly inattentive subtype. A child or adult with this type of ADHD finds it hard to remain focused, stay organized, and finish tasks. This problem was sometimes called ADD, which is now considered an obsolete term.
Predominantly hyperactive-impulsive type. Those with this form of ADHD are hyperactive (highly energetic, often too much so), restless, and impulsive.
Combined type. Someone who has both inattentive and hyperactive symptoms falls into this category.

ADHD: Statistics

Estimates vary, but according to the National Institute of Mental Health between 3 and 5 percent of American children, about two million, have ADHD. This means there is probably at least one child with ADHD in any given classroom.

While there hasn’t been a great deal of research into adult ADHD, studies show that about 4 percent of adults in the United States have ADHD — and many are unaware they have it.

ADHD: Causes

“There is no one cause of ADHD,” says Dr. Hertz. “We know that ADHD runs in families. In fact, as many as 25 percent of relatives of a child with ADHD may also have ADHD.”

According to other research, additional potential causes of ADHD include:

Environmental agents, such as the use of cigarettes and alcohol during pregnancy
Premature birth
Having had a serious head injury at a young age.

“High levels of lead are also thought to be a cause of ADHD, although this problem has decreased with the modern-day use of lead-free paint,” Hertz says. “But if a child lives in an old building where there is still lead in the plumbing or lead paint on the walls, their risk is increased.”

ADHD: What About Sugar?

“Although many parents seem to think that sugar is related to the development of ADHD, there are no studies to date that prove this,” says Hertz.

Whether you have ADHD yourself or are a parent, teacher, or friend of someone with the disorder, keep in mind that more is understood about the condition than ever before andeffective therapy exists.

Return to Child ADHD Resource Center

Last Updated: 03/10/2009