Inclusion criteria:
Healthy women aged 18-35 years
Resident in governmental or non-governmental dormitories of Tabriz University of Medical Sciences
Regular menstrual periods of 25 to 35 days over the past 6 months
Having moderate or severe premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD), based on the DRSP questionnaire filled in two following cycles
Good cooperation in filling the questionnaires at the preliminary stage of study (before randomization)
Having experience in using Internet
Regular access to Internet during study period
Having a phone number for follow-up
Exclusion criteria:
Being a professional athlete
Pregnancy or the first postpartum year
Breast-feeding
Having severe depression (score 29 or higher on Beck Depression Inventory)
Having a history of severe depression, anxiety or eating disorders in the past two years, self-report
Drug use or history of drug use during the last two years, self-report
Use of antidepressants, benzodiazepines, anticancer drugs, oral contraceptives or hormones in the past three months, self-report
Having chronic diseases (such as epilepsy, or severe digestive, cardiovascular, kidney, or gonadal disorders), self-report
Occurrence of a very stressful event in the past six months, such as: separation of parents, death of first degree family members, self-report
History of major psychiatric disorders (psychosis, bipolar disorder, suicide attempt)
Having some gynecological problems (hysterectomy, Ooforectomy, female cancer, polycystic ovary syndrome, endometriosis, infertility)