Attention Deficit Hyperactivity Disorder (ADHD) is a developmental disorder that manifests as inattentive, hyperactive, and unable to concentrate on tasks and activities. Also known as hyperkinetic impulse disorder, hyperkinesia, hyperactive syndrome, minimal brain damage, minimal brain dysfunction, and undifferentiated deficit disorder, ADHD is the most commonly diagnosed neurological disorder in children. Although many children with ADHD are quite intelligent, their lack of concentration can often lead to poor grades and low self-esteem. The exact cause of ADHD is still unknown, but it is considered highly hereditary. The results of several international twin studies have found that ADHD may have a genetic link. The presence of ADHD in a twin is most often mirrored in an identical twin who has the same genetic makeup, then in a fraternal twin whose genetics are similar but not identical. It is also believed that if a parent, uncle or grandparent had ADHD, it is more likely that their family would also develop it. No genes have been discovered that are directly related to the disorder. MRI studies comparing the brains of children with and without the condition have shown that children with ADHD have weaker brain activity in the frontal area of ​​the brain when responding to tasks requiring inhibition. For this reason, ADHD is thought to affect certain sections of the frontal cortex, parietal lobe, and possibly parts of the cerebellum. ADHD comes in three main categories; predominantly hyperactive, predominantly inattentive, or combined hyperactivity and inattention. Hyperactivity predominantly presents as excessive physical activity and impulsive behavior. This may include constant restlessness, an inability to stay on top of paper and medications, and exercise may reduce symptoms. The prognosis for ADHD is promising. Approximately 70-80% of patients treated with stimulant therapy experience significant relief from symptoms. About half of all children outgrow symptoms as they mature into adulthood, the other half retain symptoms throughout their adult lives. Works Cited Hoyle, Brian. “Attention Deficit Hyperactivity Disorder.” Gale Encyclopedia of Neurological Disorders. 2005.Enciclopedia.com. May 17th. 2012 http://www.encyclopedia.comZieman, Gayle and Dewan, Naakeesh A. “Attention Deficit/Hyperactivity Disorder (ADHD) in Adults.” RelayClinical Education. February 2012 v2012 i1 pNA“Attention Deficit Hyperactivity Disorder (ADHD).” Tish Davidson, AM., Teresa G. Odle. and Laura Jean Cataldo, RN, Ed.D. The Gale Encyclopedia of Genetic Disorders. 3rd edition. 2010.