Attention-deficit hyperactivity disorder (ADHD) is a psychiatric disorder and, more specifically, a chronic neurobehavioral syndrome. ADHD manifests as inattention, impulsivity, and hyperactivity. The term attention-deficit disorder (ADD) refers to the condition without hyperactivity.

People with ADHD tend to overlook details and to miss information. Because of attention deficit, people with ADHD become averse to tasks that require concentration, decisiveness, and organizational skills and may avoid situations where they are expected to perform or to take responsibility for their effort.

Incidence and Prevalence of ADHD

ADHD may affect as many as 10% of the population in the United States. Approximately 5% of children ages 9 to 17 have ADHD at any given time, and a possible 2–4% of adults are affected. The occurrence of ADHD is reported worldwide; statistical variations may be due to cultural perceptions of behavior.

Most studies show that in children with ADHD, boys are affected approximately five times more often than girls. Other studies suggest that the condition may not be diagnosed as often in girls because girls with ADHD present their symptoms differently.

ADHD & Prevalence

ADHD Rates Creeping Upward

Rates of attention-deficit/hyperactivity disorder, or ADHD, have crept upwards over the past few years—parents are now reporting that almost one out of 10 children and teens in the United States have been diagnosed with the condition at some point.

The Centers for Disease Control and Prevention (CDC) conducted a nationwide survey of over 73,000 children's parents between April 2007 and July 2008. The results of this survey were compared to a similar survey conducted in 2003.

The CDC analysis found that rates of parent-reported ADHD climbed from 7.8% in 2003 to 9.5% in 2007, a 21.8% increase. The survey also revealed that ADHD was reported more than twice as often in boys (13.2%) as in girls (5.6%), and two-thirds of the children and teens with ADHD were taking medication for the disorder.

An editorial that accompanied the CDC report attempted to explain the rise: "Increasing rates of estimated ADHD prevalence might indicate an actual increase in the number of cases of ADHD or changes in diagnostic practice over time, which might have been influenced by increased awareness of the disorder over the period of study."