DS is also on Singulair and has been for 6 mnths now. I haven't really noticed a change in his moods (he was always a bit whingy and had a vivid imagination) and ventalin didn't seem to have any effect. His coughing does seemed to have eased with the singulair although whenever he get's a cold/runny nose he still coughs but not all night like he was.

I really trusted his dr but he never mentioned these side effects... I really hope he isn't feeling any of them