Women who consume large amounts of caffeine are more likely to experience premenstrual syndrome, and to have more severe symptoms, reports a new study at Tufts University.

The study surveyed 295 college sophomores, 216 of whom reported experiencing premenstrual syndrome, which occurs during the second half of the menstrual cycle. PMS symptoms include one or more of the following: depression, tiredness, irritability, anxiety, headache, breast swelling and tenderness, craving for sweet or salty foods, constipation and acne.

For every category of severity, the prevalence of PMS was higher in women who consumed 4 1/2 to 15 caffeine-containing drinks a day than for women who consumed less caffeine, the study found. The drinks included coffee (32 percent), tea (19 percent) and cola (49 percent).

All PMS symptoms studied, with the "possible exception" of constipation, were "strongly asso- ciated with the consumption of caffeine-contain- ing beverages," reports the American Journal of Public Health.

The author of the study offers three possible interpretations, only one of which specifies caffeine as a direct cause of PMS. The other possibilities: Consumption of large amounts of any liquid (not just caffeine-containing drinks) may help cause PMS; or women who consume large amounts of coffee, tea and cola may differ from women who don't in a way that is somehow related to PMS.