Posted Monday, March 19, 2012 --- 7:35 a.m.

CHICAGO (AP) -- The first long-term study of the effects of methamphetamine on children whose mothers used it during pregnancy has produced results the lead researcher calls "very worrisome."

The study finds that such kids are at higher risk for behavior problems like anxiety, depression and moodiness than are other children.

Lead researcher Linda LaGasse of Brown University says the differences are not huge, but are similar to so-called "crack babies" -- children whose mothers used crack cocaine during their pregnancies.

An expert at the National Institute on Drug Abuse says the study is "groundbreaking," but since it's a first, he says the results should be viewed cautiously and need to be repeated.

The study is in Monday's Pediatrics online.

Copyright 2012. The Associated Press.