depression
"I'm a 70 year old male, in excellent physical shape, and retired.  Problem is a depression and bipolar-2 condition, both of which have haunted me pretty much my entire life.  In 1994, my depression became just unbearable, and I started on Prozac...it worked for a while...then it didn't...then we tried something else...then something else...you get the drift.  My doctor and I decided to try Viibryd; this is day 10 and I'm taking 10 mg in the morning.  This medicine is life changing.  Best news is I don't feel any sexual side-effects--actually, my sex-drive seems somewhat on the increase.  Who's complaining about that?"