ADHD

disorder characterized by lack of attention and hyperactivity (often diagnosed in children), hyperkinesis

Attention-Deficit Hyperactivity Disorder (ADHD) and Hyperkinetic Disorder (as officially known in the UK, though ADHD is more commonly used) is generally considered to be a developmental disorder, largely neurological in nature, affecting about 5% of the world's population. The disorder typically presents itself during childhood, and is characterized by a persistent pattern of inattention and/or hyperactivity, as well as  forgetfulness, poor impulse control or impulsivity, and distractibility. ADHD is currently considered to be a persistent and chronic condition for which no medical cure is available. ADHD is most commonly diagnosed in children and, over the past decade, has been increasingly diagnosed in adults. About 60% of children diagnosed with ADHD retain the disorder as adults. Studies show that there is a familial transmission of the disorder which does not occur through adoptive relationships. Twin studies indicate that the disorder is highly heritable and that genetics contribute about three quarters of the total ADHD population. While the majority of ADHD is believed to be genetic in nature, roughly 1/5 of all ADHD cases are thought to be acquired after conception due to brain injury caused by either toxins or physical trauma prenatally or postnatally. According to a majority of medical research in the United States, as well as other countries, ADHD is today generally regarded as a chronic disorder for which there are some effective treatments. Over 200 controlled studies have shown that stimulant medication is an effective way to treat ADHD. Methods of treatment usually involve some combination of medications, behaviour modifications, life style changes, and counseling. Certain social critics are highly skeptical that the diagnosis denotes a genuine impairment and question virtually all that is known about ADHD. The symptoms of ADHD are not as profoundly different from normal behavior as are those of other chronic mental disorders. Still, ADHD has been shown to often impair functioning, and many adverse life outcomes are associated with ADHD.
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Attention-deficit/hyperactivity disorder is a developmental disorder characterized by [more]ADHD - Community and Resources

Noun
1. a condition (mostly in boys) characterized by behavioral and learning disorders
(synonym) attention deficit disorder, ADD, attention deficit hyperactivity disorder, hyperkinetic syndrome, minimal brain dysfunction, minimal brain damage, MBD
(hypernym) syndrome
(part-meronym) hyperactivity

Attention-deficit/hyperactivity disorder, sometimes called ADHD, is a chronic condition and the most commonly diagnosed behavioral disorder among children and adolescents. It affects between 3 and 5 percent of school-aged children in a 6-month period (U.S. Department of Health and Human Services, 1999). Children and adolescents with attention-deficit/hyperactivity disorder have difficulty controlling their behavior in school and social settings. They also tend to be accident-prone. Although some of these young people may not earn high grades in school, most have normal or above-normal intelligence.