PMS affects women to varying degrees. For some, mild symptoms mean a monthly bout with discomfort that passes fairly quickly. For another 20 to 40 percent of women, PMS becomes a debilitating disorder that prevents them from participating in normal activities, such as work, exercise, or even interactions with their family. Of course, many women fall somewhere in the middle; their PMS is painful disruptive enough that they seek relief from their symptoms, but not so severe that they can’t function in their daily lives.

Consider this: Any woman who’s stepped on a scale a few days before her period only to find she’s gained a few pounds or who finds that her favorite jeans won’t zip up because she’s bloated has experienced PMS symptoms. As has the woman who finds she craves chocolate, potato chips or pretzels, or the woman whose skin breaks out, like clockwork, one week before her period is due. But these women may not think they have PMS; they’re simply in a bit discomfort.

There are many women with PMS who are lucky enough experience only one or two mild symptoms. Maybe they get a weepy watching a sad movie or are more tense than usual work. Perhaps they get a slight headache or can’t fall asleep as they normally do. Although these are all PMS symptoms, these women are able to get relief from over-the-counter painkillers, extra rest, some exercise.

Others aren’t so lucky. These women suffer through migraines that force them to lie down in a darkened room, or they literally can’t get out of bed. They experience significant highs and lows: alternately moody or tense, angry or sad. Their emotional and physical symptoms are marked and severe. These women may be suffering from premenstrual dysphoric disorder. PMDD is a mood disorder that is distinct from normal PMS and should be treated by a medical professional. The doctor may prescribe a class of drugs called selective serotonin reuptake inhibitors, or SSRIs, such as fluoxetine (Prozac or Sarafem), sertraline (Zoloft), or paroxetine (Paxil).