I have been taking Singulair since it has been on the market. At first along with Advair (that's another disappointment) and now with Loratadine. I have had huge problems with depression, suicide thoughts and horrific mood swings since starting Singulair. It has affected my job performance as I have no motivation to do the work. I have lost interest in being around other people and just want to stay home. I have headaches like no other headaches I ever had; experience anxiety and anger for no apparent reason; sinus problems and troubles with my tonsils getting hard, hurting and producing much crypt fluid. I really don't feel at all like me and this has caused me real concern and diminished my "friend pool" and respect among colleagues because I am erraditic in moods, avoid contact and my anxiety and lack of confidence anymore induces incessant talking. I have read many of the posts and feel so sorry that children have suffered so much taking this drug. I have been in cognitive behavioral therapy and my family physician has a real concern for my well-being and really tries to remedy my depression. I have stopped taking Singulair for 2 days and I know it is awfully soon to make any sound conclusions, but I feel stronger today and better able to cope with people. Being a teacher, I should hope so. I would have never believed that a drug for asthma/allergies would have such untoward effects. Singulair along with Advair should be removed from the market or at least only given to those who show no apparent emotional effects, it's not worth losing a life over.