anxiety
"I've taken Klonopin as needed for several years now.  It is the only thing that works when I feel a major anxiety issue coming on from progressing into a full blown debilitating attack.  However, it always helps with that, too.  

Like someone else said, it has a longer half life and you don't experience the drop off anxiety spike like some people do with Xanax.  Xanax actually made me feel more anxious when it wore off between doses.

I haven't had a problem with dependency as I only take it for a few weeks at a time every other year or so.  I'm careful to taper off over a couple weeks so I don't get rebound anxiety.

All in all, it's been a lifesaver for me."