Usually neurons recycle dopamine. But meth fools neurons into taking it up just like they would dopamine. Once inside a neuron, the drug causes it to release lots of dopamine. The dopamine rush causes an extra sense of pleasure that can last all day.

"You're flying high on dopamine until you crash," Grant said.

Even small amounts of meth can make a person more awake and active, lose their appetite, and become irritable and aggressive. It also causes blood pressure to increase and the heart to beat faster.

The same thing happens to children who are exposed. And because research has been limited, what this means for children long term isn't known.

"We don't know how much meth is absorbed if you touch that night stand or that coffee table," Erb said

Researchers do know that meth does get into children's bodies when they live with parents who make or use the drug.

"Meth itself hangs around," said Karen Buchi, a University of Utah pediatrician who studies drug effects on children.

Buchi has tested hair samples from 425 kids ages 5 to 18, including 81 who lived in homes with meth labs. Nearly half — 203— tested positive for meth, according to preliminary results.

Whether exposure results in behavioral or medical problems remains to be seen.

Preliminary results of research at Brown University show babies born to meth-addicted mothers are born small and more likely to have subtle neuro-behavioral differences. They cry a lot, Buchi explains. They are irritable, and their nervous systems are disrupted.

In addition to drug contamination, the often abusive, violent and neglectful environment in which children grow up causes social and behavioral problems.

"It's not surprising that these kids have development delays because if you're on meth, you're not going to be reading to your child," Grant said. "I think if these kids can learn at all, it's a miracle."

Researchers need to get a better understanding of how meth and the lifestyle surrounding it impact children, Buchi said.

"We still have a ways to go to make sure we are changing the trajectory for these children."

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