ADHD in Children Health Center

Understanding ADHD -- the Basics

What Is Attention Deficit Hyperactivity Disorder?

Attention deficit hyperactivity disorder, or ADHD, is a condition characterized by persistent inattention, hyperactivity, and/or impulsivity. ADHD begins in childhood and persists into adulthood in the majority of cases.

ADHD is one of the most common mental health disorders diagnosed among children. It affects 3% to 7% of all children, perhaps as many as 2 million American kids. Two to four times more boys than girls are affected. On the average, at least one child in every classroom in the U.S. needs help for the disorder.

ADHD affects over 4% of adults as well. Approximately 30% to 50% of children with ADHD continue to have symptoms of the condition that affect their functioning as adults.

Symptoms of ADHD can differ from person to person, but involve some combination of difficulty regulating activity level (hyperactivity), inhibiting behavior (impulsivity), and attending to tasks (inattention). When activity levels are normal or low, it is usually called attention deficit disorder (ADD). The symptoms of hyperactivity and possibly impulsiveness appear to diminish with age.

Children with ADHD have trouble functioning at home and in school and often have trouble with friends. If left untreated, ADHD has also been shown to have detrimental effects on academic and job performance, as well as on social and emotional development. As they grow older, children with untreated ADHD, in combination with conduct disorders, may become anti-social, use drugs, or have other criminal behaviors. 

ADHD is more common in boys, whose impulsivity and hyperactivity may be evident. Inattentiveness is a hallmark of ADHD in girls, but because they aren't disruptive in the classroom, the diagnosis may be overlooked.

ADHD tends to run in families. When one person is diagnosed with ADHD, there is a 25%-35% chance that another family member will also have the condition, compared to 4%-6% of the general population. Even more convincing of a possible genetic link is that when one twin of an identical twin pair has the disorder, the other is likely to have it, too.

No one knows for sure whether ADHD is more common today, but it is very clear that the number of children getting treatment for ADHD has risen over the past decade. Some of this increase in diagnosis and treatment is due in part to greater media interest, heightened consumer awareness, and the availability of effective treatments. Some experts feel that ADHD is overdiagnosed, while others feel it is underdiagnosed. Whether the frequency of the disorder itself has risen remains unknown and needs to be studied.