All of the following are essential features of Attention Deficit Hyperactivity Disease (ADHD) EXCEPT

(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.