According to Jo Oliver "Several studies this month in the Journal of Health Economics are looking at ADHD. Separate studies by researchers at North Carolina State University, Notre Dame, the University of Minnesota, and Michigan State University all arrive at similar conclusions about ADHD.
For those unfamiliar with ADHD or attention deficit hyperactivity disorder, it is one of the most common neurobehavioral disorders of childhood. Children with ADHD typically have trouble paying attention, controlling impulsive behavior, and/ or are overly active. The causative and risk factors for ADHD are unknown, but current research has shown that genetics plays an important role. According to CDC data and statistics: As of 2006, there are 4.5 million 5 to 17-year-old children diagnosed with ADHD. Diagnosis of ADHD increased an average of 3% per year from 1997 to 2006. Prevalence also varies substantially by state; for example, Colorado with 5% vs. 11.1% in Alabama."
For more on this article see: Studies Claim That One Million Children Misdiagnosed with Attention Deficit Hyperactivity Disorder