Gotta know ‘em. Wikipedia is happy to help.
It’s helpful to draw out a little grid with the whole gang of mood swings: MDD (big down), Dysthymia (medium down, 2+ years), Bipolar I (big up), Bipolar II (medium up), Cyclothymia (medium swings). If you’ve done a chart you’d like to share, send it on over, I’ll post it: socialworkprep [at] gmail.com.

