Someone I know very well takes singulair. It’s somewhat expensive, but it appears to work very well in keeping asthma under control and reducing the need for inhalers. I have not seen any sign of suicidal behavior.
My allergist said Singulair either works great or not at all depending on the individual. It didn’t work at all for me, although I never had suicidal thoughts or depression. Symbicort works great for me although it’s more expensive.