<prompt> All of the following are essential features of Attention Deficit Hyperactivity Disease ADHD EXCEPTLack of concentrationImpulsivityMental retardationHyperactivity  <response>: C Mental retardation Attention deficit hyperactivity disorder ADHD is seen in 3 of school age children onset occurs before age of 7 years mainly 4th year Types: with hyperactivity, without hyperactivity, residual type, conduct disorder. Mental retardation should always be excluded before making a diagnosis of attention deficit hyperactivity disorder. Symptoms: Poor attention span, hyperactivity, impulsivity. Treatment: Dextroamphetamine and methylphenidate are the drugs of choice. Attention deficit hyperactivity disorder is the most common neurobehavioral disorder of childhood. According to fourth edition of American Psychiatric Associations diagnostic and statistical manual DSM IV. ADHD is characterized by - Inattention Hyperactivity Impulsivity Diagnostic criteria for Attention Deficit Hyperactivity Disorder ADHD have been elaborated. 