Attention deficit-hyperactivity disorder (ADHD) is a mental disorder and neurobehavioral disorder characterized by either significant difficulties of inattention or hyperactivity and impulsiveness or a combination of the two.
According to the Diagnostical and Statistical Manual of Mental Disorders, symptoms of ADHD emerge before seven years of age.
There are three subtypes of the disorder which consist of it being predominantly inattentive, predominantely hyperactive-impulsive, or the two combined.
Often people refer to ADHD as “attention deficit disorder” (ADD) as well, however, the latter has not been officially accepted.
ADHD impacts school-aged children and results in restlessness, acting impulsively, and lack of focus which impairs their ability to learn properly.
ADHD is the most commonly studied and diagnosed psychiatric disorder in children, affecting about 3 to 5 percent of children globally and is diagnosed in about 2 to 16 percent of school-aged children. It is a chronic disorder with 30 to 50 percent of those individuals diagnosed in childhood continuing to have symptoms into adulthood.
Adolescents and adults with ADHD tend to develop coping mechanisms to compensate for some or all of their impairments. ADHD is diagnosed two to four times more frequently in boys than in girls. Its symptoms can be difficult to differentiate from other disorders, increasing the likelihood that the diagnosis of ADHD will be missed. In addition, most clinicians have not received formal training in the assessment and treatment of ADHD, in particular in adult patients.
(Information supplied by Wikipaedia)