One culture may report different symptoms from another culture, but women from all walks of life are affected.

But only 5 to 10 percent report symptoms severe enough to interfere with daily life, according to the American College of Obstetricians and Gynecologists (ACOG).

Premenstrual dysphoric disorder (PMDD) is usually used as a designation for severe cases of PMS. ("Dysphoric" means the opposite of "euphoric," which is a comfortable, happy feeling.)

Some women have physical changes; others have emotional changes. Not all women have all symptoms, according to the National Women's Health Information Center. Of the 150 symptoms, these are among the most significant: Physical symptoms include abdominal bloating, headache, weight gain, and breast swelling. Emotional changes include irritability, mood swings, food cravings, and tension. Mental changes include depressive mood, anxiety, lack of concentration, and poor control of impulses.

It can also be confused with diabetes, thyroid problems, allergies, and endometriosis, the ACOG says.

The exact mechanisms that cause PMS aren't yet understood, but serotonin, testosterone (produced in small quantities by the ovaries), and estrogen, plus other hormones and chemicals, may play a role, the ACOG says.

Symptoms appear after ovulation, about the 14th day of a woman's monthly cycle, and disappear two weeks later, when her period begins, according to the ACOG. In addition, the symptoms must impair the patient's life. Other illnesses, such as depression, must also be ruled out before a diagnosis of PMS can be made. (PMS can co-exist with and may exacerbate other illnesses and conditions, however. Asthma symptoms, for instance, can worsen with PMS.) Typically, a doctor will ask a patient to keep a diary of symptoms for two to three months before making a diagnosis.

The doctor may recommend taking calcium, magnesium, and vitamin E to help relieve symptoms. Recent research has indicated that estrogen regulates the levels of calcium and magnesium in the body, so taking additional calcium may help symptoms. Taking magnesium does not appear to help. For severe cases of PMS, a doctor may prescribe an antidepressant known as a serotonin selective reuptake inhibitor.