Attention-deficit/Hyperactivity disorder (ADHD) is a developmental disorder characterized by distractibility, hyperactivity, impulsive behaviors, and the inability to remain focused on tasks. The National Institutes of Health (NIH) regards ADHD as the most commonly diagnosed behavioral disorder of childhood and thus, a major public health problem.

ADHD is also known as hyperkinetic disorder (HKD) outside of the United States. Studies done in Japan, China, Germany, France, Holland, Sweden and North America suggest that 3-9% of children are affected. In the United States, this translates to an estimated 2 million children with ADHD. The condition afflicts boys more often than girls. Some children suffer primarily from inattentiveness rather than from hyperactivity and are classified as having Attention Deficit Disorder (ADD).

Although difficult to assess in infancy and toddlerhood, signs of ADHD may begin to appear as early as...