In the past decade the rate of children diagnosed with ADHD increased by two million and one million more kids were being medicated for the condition.

The number of children between the ages of four and 17 years of age who were diagnosed with ADHD (about 11 percent of the U.S. population) has risen by about 42 percent since 2003, an Elsevier news release reported in reference to a Centers for Disease Control and Prevention (CDC) study. This number encompasses 6.4 million children.

Over 3.5 million U.S. children were reported to be taking ADHD medications last year, that is a 28 percent increase since only the 2007 to 2008 period.

"This finding suggests that there are a large number of young children who could benefit from the early initiation of behavioral therapy, which is recommended as the first-line treatment for preschool children with ADHD," Susanna Visser, of the Centers for Disease Control and Prevention and the lead author of the study, said.

ADHD is one of the most commonly diagnosed neurobehavioral disorders in children, and the condition often continues into adulthood, the news release reported.

"This finding raises concerns about whether these children and their families are receiving needed services," Doctor Michael Lu, Senior Administrator, Health a Resources and Service Administration (HRSA), said in the statement.

The new research suggests half of all children diagnosed with ADHD are so before the age of six. Half of children with severe ADHD receive their diagnosis before the age of four.

"Children with ADHD may have trouble paying attention and/or controlling impulsive behaviors. Effective treatments for ADHD include medication, mental health treatment, or a combination of the two. When children diagnosed with ADHD receive proper treatment, they have the best chance of thriving at home, doing well at school, and making and keeping friends," the news release reported.