Recognizing Crucial Differentiating Features When Diagnosing Bipolar Disorder Vs. PMDD
Premenstrual syndrome (PMS) is an extremely common condition, affecting up to 85% of menstruating women.1 Between 2% and 10% of women experience severely disabling and incapacitating symptoms.1,2 Although more than 200 symptoms are associated with PMS, irritability, tension, and dysphoria are the most prominent and consistently described.3 Women whose affective symptoms are especially severe may meet criteria for premenstrual dysphoric disorder (PMDD).3
PMS is cyclical, with symptoms arising during the luteal phase of the menstrual cycle and lasting until the onset of menstrual flow, when symptoms typically abate.3 During the follicular phase prior to ovulation, estrogen levels rise, while during the luteal phase following ovulation, progesterone levels rise. Immediately before the onset of menstruation, estrogen and progesterone levels both decrease.4
Estrogen is considered to exert a generally positive effect on serotonergic neurons and on their cortical postsynaptic targets, thereby conferring some protection against depression.5 However, estrogen levels may be less implicated in premenstrual depression than hormonal fluctuation. Depression in women particularly occurs at times of hormonal flux (i.e., prior to menstruation, following childbirth, and during menopause).6
Bipolar disorder and severe premenstrual syndrome (PMS) have many similar symptoms. Both are characterized by cycling moods, including severe depression.6 Because of the overlap in symptoms, severe PMS is often misdiagnosed as bipolar disorder. In an article titled "Severe Premenstrual Syndrome and Bipolar Disorder: A Tragic Confusion,"6 author Studd points out that severe PMS is frequently treated with psychotropic medications, such as antidepressants and mood stabilizing antiepileptic agents, rather than therapies designed to suppress cyclical hormonal changes. He describes this confusion as "tragic" because these inappropriate therapies are often ineffective and can be damaging. According to Studd, effective treatment utilizes transdermal estradiol or gonadotropin-releasing hormone (GnRH) analogues, which suppress ovulation. He notes that "It has been observed that longstanding 'bipolar depression' . . . often disappears when the cyclical premenstrual nature of the condition is treated by suppression of ovarian cycles."