There is evidence that a brain chemical called serotonin plays a role in a severe form of PMS, called Premenstrual Dysphoric Disorder (PMDD). The main symptoms, which can be disabling, include:

* feelings of sadness or despair, or possibly suicidal thoughts

* feelings of tension or anxiety

* panic attacks

* mood swings, crying

* lasting irritability or anger that affects other people

* disinterest in daily activities and relationships

* trouble thinking or focusing

* tiredness or low energy

* food cravings or binge eating

* having trouble sleeping

* feeling out of control

* physical symptoms, such as bloating, breast tenderness, headaches, and joint or muscle pain

You must have five or more of these symptoms to be diagnosed with PMDD. Symptoms occur during the week before your period and go away after bleeding starts.

Antidepressants called selective serotonin reuptake inhibitors (SSRIs) that change serotonin levels in the brain have also been shown to help some women with PMDD. The Food and Drug Administration (FDA) has approved three medications for the treatment of PMDD:

* sertraline (Zoloft®)

* fluoxetine (Sarafem®)

* paroxetine HCI (Paxil CR®)

Individual counseling, group counseling, and stress management may also help.