I am so glad that I found this site, my son is 5 1/2 and has been taking Singulair since he was two. It works, but the side effects are not worth it. He is our first child so we attributed his behavior to the terrible two's, terrible three's when he started pre-k we thought it was immaturity, now he is in kindergarten and the teacher reports restlessness, inability to concentrate, clumsiness, all types of issues that could be related to ADHD. We were about to start the process to see if he had ADHD when I found this website. He has been off of the med for two weeks today. He went to the pediatrician, eye doc and allergist. All say he is in good health and that he can sit still for their exams, doubting ADHD. The pediatrician wants us to wait another two weeks and then look at his behavior in school and see if it has changed. It's hard to get an ideas as to how long before the effects of the pill will wear off. I have read entries that say one day, to entries that say up to 6 months. I have seen a change at home, he states he is less "squirmy." The allergist says that this effect on children is rare, but he did admit that it happens. He has seen 3 cases in 6 years.