As mentioned previously in our daily facts about ADD for the month, ADD is a term that is no longer used on its own. Today ADD is diagnosed as ADHD Inattentive type.
According to research gathered by the Centers for Disease Control and Prevention from the National Survey of Children’s Health, ADHD is more common in the Eastern side of the United states.
The research does not indicate any reason to why ADHD is more commonly diagnosed in the East. There are no indications of environmental factors being greater in the area. Simply, the answer is the reason for more diagnoses in the East is unknown, and it cannot be tested at this time.
This map from the CDC shows prevalence in 2011.
Source: http://www.cdc.gov/ncbddd/adhd/prevalence.html#current