anxiety
"I have been on this for 4 months now and LOVE the results. I used to lay awake for hours worrying about everything and my negative thoughts made it impossible to sleep. Then there were the nightmares and panic attacks etc.
There is only one real negative side effect and that is that I can no longer orgasm. My libido used to be through the roof! Now I am unable to get aroused...nothing works. It's extremely frustrating. 
I have also gained weight. The good thing is, I am always in such a good mood that I fail to care."