Most researchers today agree that PMS is a real physical condition with a real physiological basis. Beyond that, a precise definition is difficult. In general terms, it is a “syndrome” or a series of symptoms, which appear each month in a pattern, related to the menstrual cycle. Symptoms can occur as a combination of physical, psychological or behavioral changes. The range and severity of symptoms differ from woman to woman. If you think you have PMS, you should consult your healthcare provider. The single best diagnostic tool you and your doctor can use is a daily diary or calendar noting the timing and pattern of your symptoms for at least one month, and preferably three months. Just as there is no single cause, there is no single treatment. But there is treatment. And with planning and forethought, you can be just as prepared for “the period before your period” as you are for your period itself.