The previous symptoms must occur in addition to the required physical and mental symptoms required for PMS diagnosis for diagnosis of PMDS to occur.
Sources: The American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Washington, DC, American Psychiatric Association 1994
Robert F Casper, MD. Patient information: Premenstrual syndrome and premenstrual dysphoric disorder (PMDD), Clinical manifestations and diagnosis of premenstrual syndrome and premenstrual dysphoric disorder, UpToDate [online]. Accessed on October, 24, 2006