Attention-Deficit/Hyperactivity Disorder (ADHD)

What is ADHD?

Attention-deficit hyperactivity disorder (ADHD) is a neurobehavioral condition with symptoms that include excessive restlessness, poor attention, and impulsive acts. Estimates show that between 3 and 7 percent of school-aged children and about 4 percent of adults have ADHD.

No single biological cause for ADHD has been found. But most research points to genes inherited from parents as the leading contributor to ADHD. For example, studies clearly show that ADHD runs in families—seventy-six percent of children with ADHD have a relative with the condition.

Scientists are currently looking for which genes, or combinations of genes, influence how ADHD affects the behavior of those with the condition. Being born prematurely, maternal smoking or extreme stress during pregnancy, being exposed to alcohol in the womb, and traumatic brain injury also may contribute to the development of ADHD.

A person with ADHD is so inattentive or impulsively hyperactive — or both — that daily functioning at home, school and work is compromised. ADHD usually becomes apparent in children during preschool and early school years.  

ADHD has three subtypes:

• Predominantly hyperactive-impulsive

–  Most symptoms (six or more) are in the hyperactivity-impulsivity categories.

–  Fewer than six symptoms of inattention are present, although inattention  may still be present to some degree.

• Predominantly inattentive

–  The majority of symptoms (six or more) are in the inattention category and fewer than six symptoms of hyperactivity-impulsivity are present, although  hyperactivity-impulsivity may still be present to some degree.

–  Children with this subtype are less likely to act out or have difficulties getting along with other children. They may sit quietly, but they are not paying attention to what they are doing. Therefore, the child may be overlooked, and  parents and teachers may not notice that he or she has ADHD.

• Combined hyperactive-impulsive and inattentive

–  Six or more symptoms of inattention and six or more symptoms of  hyperactivity-impulsivity are present.

–        Most children have the combined type of ADHD.

Treatments can relieve many of the disorder’s symptoms, but there is no cure. With  treatment, most people with ADHD can be successful in school and lead productive lives. Researchers are developing more effective treatments and interventions, and using new tools such as brain imaging, to better understand ADHD and to find more effective ways to treat and prevent it.