Attention-Deficit/Hyperactivity Disorder (ADHD)

To find patient care programs and faculty treating attention-deficit/hyperactivity disorders at Kennedy Krieger Institute, as well as research investigating this disorder, please see the right-hand column below. Additional helpful information, including definitions, symptoms, Institute press releases, Potential magazine articles, and other resources outside the Institute, have also been provided for readers on this page.

Attention-Deficit/Hyperactivity Disorder Overview:

Attention-Deficit/Hyperactivity Disorder (ADHD) is a condition that can make it hard for a person to sit still, control behavior and pay attention. These difficulties usually begin before the person is seven years old. However, these behaviors may be noticed earlier or may not be noticed until the child is older.

Doctors do not know what causes ADHD. However, researchers who study the brain are coming closer to understanding what may cause ADHD. They believe that some people with ADHD do not have enough of certain chemicals (called neurotransmitters) in their brain. These chemicals help the brain control behavior. To take part in research on ADHD, please download the PDF at the bottom of the screen.

As many as five out of every 100 children in school may have ADHD. Boys are three times more likely than girls to have ADHD.

There are three main signs, or symptoms, of ADHD. These are:

  • problems with paying attention
  • being very active (called hyperactivity)
  • acting before thinking (called impulsivity)

Based on these symptoms, three types of ADHD have been found:

  • Inattentive Type: The person can’t seem to get focused or stay focused on a task or activity
  • Hyperactive-Impulsive Type: The person is very active and often acts without thinking
  • Combined Type: The person is inattentive, impulsive and too active

When a child shows signs of ADHD, he or she needs to be evaluated by a trained professional. A complete evaluation is the only way to know for sure if the child has ADHD.

Examples, Subsets and Synonyms for Attention Deficit Disorders (minimal brain dysfunction, hyperkinetic syndrome):

  • Attention Deficit Hyperactivity Disorder (ADHD)
  • Inattentive Type
  • Hyperactive Type
  • Mixed Type
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