PMDD is something that is meant to be 'more severe' than PMS, but neither are included in the DSM-IV as disorders. PMDD was last labelled in DSM as something requiring further investigation.

i have spoken to my pdoc about it - a fair few times, actually. i think he might have even monitored my cycle on the sly (gross!). but he seemed to know a heap about it, and when i spoke to my GP she agreed - the pill *can* be useful in helping it, but the best treatment for PMDD is an SSRI, so try that as first avenue therapy. something about the pill containing something in it which is linked to starting PMDD in the first place.

http://en.wikipedia.org/wiki/PMDD for info on it, and they have links for further info at the bottom of the page.