Attention deficit hyperactivity disorder (ADHD) refers to a group of symptoms that begin in infancy and can continue into adulthood, causing difficulties for people at home, at school, at their jobs, and within their communities. The severity of symptoms varies among people with ADHD. Some people have difficulty with over activity (hyperactivity), while others have difficulty remembering, thinking, making judgments, and solving problems.
             The person who has an attention deficit hyperactivity disorder with no other conditions tends to do better in school and to get along better with other people than the person who has ADHD together with other conditions. ADHD (with or without other conditions) may lead to anxiety or depression, poor school performance, and problems with social behavior. The exact cause of attention deficit hyperactivity disorder is not known. There is evidence that ADHD is an inherited disorder. Studies have shown that about 30% of children with ADHD come from families in which other members have the disorder. Siblings of children who have ADHD are twice as likely to have ADHD as siblings of children who do not have ADHD.
             Another possible cause of ADHD is an abnormal functioning of the chemical systems within the brain. Studies indicate that people with ADHD may not have enough of a brain chemical called dopamine and too much of a brain chemical norepinephrine. It is thought that abnormal functioning of part of the brain may be another cause for ADHD. Areas of the prefrontal lobe in people with ADHD appear different from these areas in people who do not have ADHD. Some other suggested causes of ADHD include, alcohol or other drug use during pregnancy, problems during delivery like anoxia that causes injury to the brain , infections that cause brain damage, and poor nutrition during the baby's first year of life
             Contrary to a widespread belief among parents and many child-care workers, ADHD is rarely caus...