Attention Deficit Hyperactivity Disorder (ADHD) is a syndrome that manifests itself as a cluster of behaviors that are, more often than not, seen together. The main behaviors observed in an individual with ADHD are impulsivity, inattention and hyperactivity. People with ADHD may have trouble sitting still, controlling their impulses, and paying attention. These behaviors can lead to problems at school, at work, and in the home.
From 3 to 7 percent of school-age children (including teenagers) in the United States and Canada have ADHD. It is diagnosed, or determined, more often in boys than girls, although it occurs equally in both. ADHD affects children across all ranges of intelligence and ability. Most children with ADHD are of normal intelligence, or even smarter than average. ADHD has no prejudice; it does not discriminate. It transcends socio-economic, cultural and racial groupings.
Many causes of ADHD have been suggested in recent years. Some ideas have proven to be wrong. Other ideas are getting scientific support. The exact cause of ADHD, however, remains unknown.