I took Singulair for a little over a year. In that time I have quit my job of six years, dropped college classes that I was previously excited about, and generally didn't give a damn any more about anything. My dreams became dark and horribly violent nightmares leaving me shaken throughout the day. I couldn't concentrate and was thinking I should seek professional help. My wife was worried that it was her and I couldn't figure out what my problem was.
About 6 or 7 weeks ago I heard there had been links to mood swings and depression from taking Singulair and immediately stopped taking it. It sounds cloche but it was as if the clouds parted and the sun began to shine again. I have become much more like my old happy and motivated self. My wife has noticed a huge difference as well as my friends and former coworkers. I am still having a little bit of a hard time staying on task but each day gets better and better. I sleep much better and the nightmares have stopped.
I think I'd rather deal with the allergy symptoms rather than take the FDA sanctioned poisons put out by firms like Merck. Their practices are criminally negligent but nothing will probably come of it because the regulatory agencies are in their pockets. It's all about the bottom line profits--public health be damned.