Premenstrual syndrome (PMS) is a term used to describe a group of symptoms that you may experience up to seven to 10 days before your period begins and goes away when your period begins or soon after. PMS can include emotional symptoms such as crying or crankiness, and physical symptoms such as bloating, breast tenderness or headaches. If you have PMS, you're not alone. While about 75 percent of girls and women who menstruate experience some type of menstrual-cycle discomfort, 30 to 40 percent of them experience symptoms severe enough to disrupt their normal activities. These are the symptoms known as PMS.

Premenstrual dysphoric disorder
Premenstrual dysphoric disorder (PMDD) is a severe form of PMS that affects about five to seven percent of girls and women who menstruate. The effects of PMDD can make it tough to function at school and in relationships.

Symptoms include:

• Severe mood swings, depression, irritability and anxiety. Do you experience uncontrollable crying jags or anger, or depression so intense you can't function? Emotional symptoms are the ones most likely to lead your health care professional to conclude you have PMDD.
• Sleep disturbance. Do you experience insomnia (inability to sleep) or need excessive sleep just before your period?
• Difficulty concentrating. Is it impossible or nearly impossible to study or pay attention in class.
• Breast tenderness and bloating. Do your clothes feel too tight? Do your breasts ache?

If you think you might have PMDD, try lifestyle modifications recommended for PMS and talk to a health care professional. Many of the emotional symptoms appear to be associated with low levels of a brain chemical called serotonin. Medication is available that can increase the amount of serotonin in the brain, thereby treating PMDD.