depression
"I've been on this medication for a week to treat my low grade depression which has manifested itself primarily with erectile dysfunction and insomnia.  I am 22.  Within 48 hours, I slept through the night for the first time in months.  Much of the sexual difficulties I had experienced prior to taking the Pristiq (which is the first antidepressant I've been on) went away within the same time period.

I'm yawning a lot despite not being particularly tired and I'm clenching my jaw a lot.  I'm more focused, excited about my sex life and just being able to sleep through the night for once is a God send.  If these are the worst side effects I have to deal with, I'll be happy."