From GnRH to SSRIs and Beyond: Weighing the Options for Drug Therapy in Premenstrual Syndrome

In This Article

Differential Diagnosis of Premenstrual Syndrome

Because premenstrual syndrome (PMS) may mimic a number of other affective and behavioral syndromes as well as medical conditions, an accurate diagnosis of PMS is required before deciding what would be appropriate therapy. The condition most easily confused with PMS is premenstrual exacerbation of affective disorder. If this condition is not excluded, as many as 50% of patients diagnosed with PMS will be found to have an underlying mood disorder (Table I). In addition to mood disorders, PMS should be differentiated from premenstrual exacerbations of anxiety disorder, thyroid disorder, and chronic medical conditions such as diabetes, all of which which may present with the profound fatigue often seen in PMS. In addition, PMS must be distinguished from perimenopausal symptoms (particularly in patients older than 40 years of age) and from mood alterations induced by ovarian-steroid-containing preparations such as oral contraceptive pills.

In a study of 263 women presenting with the complaint of PMS, researchers at the University of California at San Diego observed that 10.2% experienced early menopausal symptoms, and 20.5% either reported no symptom-free interval or were found to have no such interval on prospective recording. An additional 11% had affective or personality disorders, 10.6% were using hormonal contraceptives, 5.3% had eating disorders, 3.8% were alcohol or other substance abusers, and 8.4% had symptoms that could be attributed to a previously diagnosed medical disorder such as diabetes or hypothyroidism. As many as 16.6% of subjects had menstrual irregularities, precluding the conviction that symptoms were related to the menstrual cycle. Overall, more than 75% of patients presenting with the complaint of PMS had another condition that either could account for the symptoms or that required correction before an accurate diagnosis of PMS could be made.[1]

The hallmark of the diagnosis of PMS is the presence of a relatively symptom-free interval between days 12 and 14 of the menstrual cycle. Because recall is poor, this symptom-free interval must be ascertained by prospective recording. Although many of the scales frequently used to measure PMS symptoms are retrospective in nature, these are not acceptable in making an accurate diagnosis.[2] Several prospective rating scales,[3,4] such as the Calendar of Premenstrual Experiences (COPE), available through the University of California at San Diego,[5] provide valid, reliable, and simple-to-use measures of PMS symptoms (Fig. 1). Patients should be given a list of symptoms--specific criteria for diagnosis of PMS--to accompany the instruments used. In general, however, a score during the last week of the menstrual cycle, which is at least 50% higher than the score during days 3 to 9 of the menstrual cycle, provides strong evidence for the diagnosis of PMS.

Figure 1. A calendar for rating the presence and severity of premenstrual symptoms daily can reveal hallmark patterns needed to make the diagnosis of PMS.

In addition to the timing of symptoms and the exclusion of psychiatric and medical disorders, the diagnosis of PMS requires that symptoms be present in the absence of pharmacologic interventions, particularly oral contraceptive agents. Diagnostic criteria incorporating these exclusions have been developed by our own group independently (Table II).[6] In a consensus reached at an unreported National Institute of Mental Health (NIMH) conference, participants emphasized the importance of at least a 30% increase in symptom scores to establish the diagnosis of PMS. An instrument like the COPE calendar is well suited for rating PMS symptoms.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: