Attention deficit hyperactivity disorder is seen in

ADHD: Attention Deficit Hyperactivity Disorder. Difficulty in paying attention, difficulty in controlling behavior and hyperactivity. Etiology- both genetic and environmental factors. Abnormality in dopamine transporter and thyroid receptor beta genes in some patients. Three subtypes are known: Predominantly hyperactive-impulsive Predominantly inattentive Combined hyperactive-impulsive and inattentive. Diagnosis is primarily clinical, using thorough clinical interview of parents and use of behavior rating scales. Physical examination includes direct observation of the child and ruling out chronic systemic illnesses that affect child's attention span.