The Core Symptoms of Premenstrual Syndrome
This is very interesting research. A paper from earlier this year showed that there are core symptoms that distinguish PMS.
http://www.liebertonline.com/doi/abs/10.1089/jwh.2010.2161
It is pretty interesting, it seems to be true that most women with PMS have one or more of the core symptoms (and alot of women have all six!)
I wrote an article based on this research:
http://www.pmscomfort.com/pms-symptoms/what-is-pms.aspx
How many of the core symptoms do you have before your period?