Exposure to Lead or Prenatal Smoking Increases Changes of ADHD

The online journal Environmental Health Perspectives posted a study that found children whose mothers smoked during pregnancy were two and half times more likely to have ADHD. Increased lead levels appear to increase a child's risk as well.

"The study builds on previous research, but offers one of the first estimates of how much those factors contribute."

Lead levels that seemed to contribute to ADHD, disturbingly enough, are levels that are considered "acceptable" by the U.S. government.