I was diagnosed with bipolar disorder about 20 years ago and from my personal experience the inability to feel emotion goes with the territory. I tend to create drama for myself and others around me because I need an intensity of pain great enough to bring those feelings back.

As far as meds making me dull, I feared that too. I cant speak for all meds, but Lamictal does a great job without any personality loss. Maybe the first couple of weeks I was on edge, but after that I havent even thought about it.