Fortunately for the 2%–5% of women who suffer from this debilitating disorder, physicians who provide care for these women and scientists exploring the causes of PMDD have not been swayed by these arguments. Late luteal phase dysphoric disorder (LLPDD) was included in Appendix A of DSM-III-R in 1987 (2), and research continues to codify the type of symptoms experienced by the most affected women, to confirm their temporal association with menstrual cycle phases and related hormonal changes, and to study the efficacy or lack thereof of various pharmacological and hormonal treatment strategies (3, 4). With this said, the application of modern scientific techniques to the study of premenstrual disorders over the past 40 years has lagged behind the study of brain disorders in general. Peripheral markers of CNS dysfunction were examined in schizophrenia in the early 1970s, but not until 1987 did Rapkin et al. (5) report abnormalities in whole blood serotonin in PMS. Likewise, the first psychophysiological techniques were applied to the study of schizophrenia in the early 1970s and to anxiety disorders soon thereafter. No publications described the results from an acoustic startle study in women with PMDD until 2007, when menstrual cycle phase-by-diagnosis differences in baseline arousal were observed (6). Magnetic resonance (MR) techniques were first used in the study of psychiatric disorders, in this case schizophrenia, in the early 1980s, but the application of brain imaging techniques for PMS and PMDD would not occur for another two decades (7, 8). If one assumes that the advent of modern research in the pathophysiology of premenstrual disorders is temporally linked to the inclusion of LLPDD in the appendix of DSM-III-R in 1987, it may be safe to say that the inclusion of PMDD as a full diagnosis in DSM-5 will further galvanize the study of this important disorder.