Seth Stevenson, a writer for Slate Magazine and self-described shy person, put himself on Paxil for a month in an experiment to see if he could become extroverted.  He chronicled the ensuing personality transformation, emotional detachment and eventual withdrawal in this powerful article.  Wow.

Movies, once a favorite hobby, do nothing for me now. Likewise books—I just don’t connect with the plots or characters. I can’t recall laughing (while sober) in the past couple of weeks. I’m never sad, but never happy.