I am a mom of twin boys who are 3 1/2. They were 9 weeks premature so we battled RSV for the first two years of their life. Allergies are also an issue therefore, they were put on Singulair at 10 months old. It really seemed to work for them and things seemed to be going okay but once they turned 1 1/2, their behavior started to change. They were constantly throwing toys at each other, sippy cups at people across the room, screaming for no reason, etc. Some may say it was normal behavior for little toddlers. Then the "terrible two's" set in. They started biting, pushing, screaming over anyone who talks to get attention, not listening and for two kids that slept through the night....all of a sudden that stopped too! My husband and I mentioned it to the pediatrician and also tried to going through the state (developmental clinic because of being premature) thinking that we would get some answers and everyone seemed to think it is a combination of their age and the fact there are two of them....sibling rivalry. We now deal with two kids that use to sleep through the night, now end up in our bed every night to fall asleep because they don't like their room and their erratic behavior is stressing my husband and myself out. When they are good, they are great but when it gets bad....it is a nightmare! I even find it hard to get people to watch the kids because they are too much to handle! After reading these postings I realize I am not the only one with kids going through this and that the common link is SINGULAIR! I am not giving this to my boys ever again and I already put a call into the pediatrician to discuss my findings. I have a sense of relief to know that it is not only my children who's behavior is like this but I am scared because I pray that there is not any long term effects that can not be corrected once this drug is out of their system. I just want my boys to be healthy and okay!