My daughter is three and a half. She has been a Singulair since she was 18 months old. She has also been on oral pred, xopenex, pulmicort for her asthma. Last fall, her pediatrician (the same doc who put her on Singulair) diagnosed her as hyperactive and probably attention deficit. She is often difficult to manage. Her pre-school teacher has complained that she is disruptive in class. She speaks at a shout, is demanding and interrupts people constantly. She has been gaining weight -- and I'm worried that even though she is 3 1/2 she is wearing a size 5. She has also developed the hard-blink tic. Her pediatrician has recommended she see a neurologist for the tic. Thanks heavens a neighbor saw a news story on the side effects of singulair and told me about them. I am taking her off the drug now.