Introduction: Many women in fertile period of their lives experience some bothering mental and physical symptoms that begin around 7-10 days before menses (lutheal phase) and cease in the first days of menstrual bleeding. After presentation of the Text Revision of the Fourth version of Diagnostic and Statistical Manual of psychiatric disorders (DSM-IV), these symptoms already known as Pre-menstrual syndrome (PMS) were called Pre-menstrual dysphoric disorder (PMDD). This process was associated with addition of some criteria about duration and intensity. The prevalence of PMS has been estimated to be about 40% to 70% but severe signs (PMDD) have lower prevalence. This study has evaluated the frequency of PMS and PMDD and some related factors in students of girls’ high schools in Kermanshah. Methods and Materials: In this descriptive-analytic study, 800 students of girls’ high schools were chosen by randomized cluster sampling. A researcher made questionnaire assessing PMS and PMDD according to DSM.IV.TR criteria as well as a demographic questionnaire were administered to participants. Data were analyzed running SPSS software -version 11.5. Findings: Frequencies of PMS and PMDD were 41.5% and 9.4% respectively. The disorder was more frequent in students older than 16 years old. Mood symptoms were the most frequent presentation, followed by physical and behavioral symptoms. There was a lower frequency of the disorder despite a higher frequency of the syndrome in students with highly educated mothers. The frequency of PMS was higher in students with positive family history. Discussion: Because of the potential adverse effects of PMS and PMDD on academic achievement and mental health of students, the high frequency of these problems need urgent attention. Planning mental health evaluations and interventions is necessary for these age group students. Diagnosis of severe cases and referring them should be considered in such programs.
