It's interesting to read about children who get angry for no apparent reason while on Singulair. We experienced this with our 5 year old son also. His Kindergarten teacher always brought this up to me that he would never take responsibility for his own actions, but blame everyone for what happened. He was the same way at home. He was extremely sensitive about everything! If we laughed he would explode thinking we were laughing at him. He constantly said that no one liked him and that he was stupid.
As soon as he was taken off the Singulair, little by little the sensitivity disappeared. He became, again, the strong confident little boy we once had.
I think this is a huge side effect of Singulair that will get over-looked because of the major side effect - suicide. If Singulair is causing children to feel such a poor self image, the side effects may well linger on longer than we thought. We must reassure our children that they are special, and well loved, and get them off, I'm not saying we all haven't done that because I know we have or we wouldn't be here worried sick seeking help. I just think they need that extra hug.
We actually told my son a few days after we took him off that the reason he got so angry all the time was because of singulair. We assured him that he would feel great again soon and he didn't have to worry about that "feeling" anymore. Like many other parents, even within about 3-4 days our son's personality started to shine again. What a joy it is to have him back.