I don't think it's a defense mechanism, it happens a lot per month, regardless of whether or not something sad happens.

And if I stopped taking my meds, I think it'd be much worse, Evil.

Don't get me wrong- most days in a month, I am filled to the brim with happiness- it's just days like today when I'm flat. I heard a few more voices, and saw a few more things than usual today, so maybe it's a flareup.