Almost 10 percent of U.S. kids have been diagnosed with attention deficit hyperactivity disorder (ADHD), according to a survey of parents conducted by the Centers for Disease Control and Prevention. That's a shocking 22 percent jump over 2003 figures — representing an additional 1 million children — and the increase was seen in all races, income levels, and areas of the U.S., with the exception of the West. What's behind the rise? Here are 5 theories:

1. Doctors are doing a better job of diagnosing ADHD
Improvements in screening programs and greater awareness of the disorder among parents and doctors have helped identify more cases, says CDC epidemiologist Susanna Visser, the report's lead author. "We have become much more sensitive to behavioral differences," agrees Dr. Jeffrey Brosco, an ADHD expert at the University of Miami. But that doesn't mean doctors can say "whether kids in the 1970s are really different from kids in the '90s or the 2000s."

2. Demographics
The increases were more significant in certain demographic groups, notes Scott Hensley at NPR. "The biggest jumps were seen in children between 15 and 17 and among Hispanic or multiracial children." The jump in Hispanic ADHD cases likely reflects "greater cultural acceptance of the disorder." Mysteriously, increases were particularly significant in 12 states, says Ray Hainer at CNN. North Carolina, for example saw a 63 percent spike in cases, with 15.6 percent of its kids diagnosed with ADHD.

3. Big Pharma is pushing the cure
Of the 5.4 million kids diagnosed with ADHD, the CDC reports, 2.7 million are taking medication for the condition. You have to question "the role of pharmacological companies in all of this," says University of Kentucky psychiatrist John D. Ranseen. "It is very much in their interest to increase the diagnosis and treatment of this condition." That alone should "give the mental health field pause."

4. Blame our lousy diet
Nobody really knows what causes ADHD, says David Knowles in AOL News, but "one recent study suggested a correlation with a diet high in processed and fried foods." Intriguingly, new research also ties ADHD to obesity in adulthood, says Heather Turgeon in Strollerderby. There's no proof — yet — that one causes the other, but "the two are correlated."

5. The real spike is in "paranoid" parents
"Are kids really that messed up?" asks Tom Henderson in ParentDish. "Or are parents becoming a bunch of second-party psychological hypochondriacs?" Remember, these million extra ADHD cases are "parent-reported diagnoses," and today's parents have been known to be "all too eager to control normal childhood restlessness and general weirdness by bombing kids with Ritalin." Because, after all, "children often have the attention spans of, uh, children."