My 12 year old just quit taking Singulair because of severe symptoms--bad dreams, stomach problems, inability to concentrate in school (before Singulair, he had NO issues with school work), and because of vocal tics, which he never had before Singulair. Type in "Singulair side effects" on google and you can read for hours all the heartbreaking stories about kids who've taken Singulair. Please tell me your son doesn't take it anymore! It can also cause depression, severe mood changes, anxiety--all these warnings are on the info the pharmacy gives out with Singulair. The FDA issued new warnings. It should be taken off the market!