High-fructose corn syrup, a manmade concoction that finds its way into numerous processed foods including sodas, has come under fire for possibly contributing to behavioral issues such as autism or attention-deficit hyperactivity disorder, better known as ADHD. But no study has proved that HFCS specifically -- or any other sugar -- actually causes behavioral changes in children. A Norwegian study published in the October 2006 issue of the "American Journal of Public Health" looked at behavioral issues in teens in relation to their soda intake. The study found that teens who drank the most soda -- more than four glasses per day -- had the most behavior issues, but it also found that teens who drank no soda had more behavioral issues than those drank a moderate amount. A review of 23 available studies conducted by Vanderbilt University researchers and reported in the November 1995 issue of "JAMA" found no correlation between sugar intake and hyperactivity.