Premenstrual syndrome (PMS) is characterized by a collection of mild to severe physical, affective, and behavioral symptoms experienced by about 80% of reproductive age women [1, 2]. The symptoms occur cyclically before or during the luteal phase of the menstrual cycle. Premenstrual dysphoric disorder (PMDD) is a more severe form of PMS with a greater emphasis on depressive and anxiety symptoms . The etiology of PMS and PMDD is not clearly understood but the onset of symptoms is associated with hypersensitivity to changes in the ovarian hormonal level during the menstrual cycle [4, 5], dysregulated immune function , neurotransmitter dysregulation, stress, diet, and lifestyle . Pharmacological interventions include analgesic treatment, combined oral contraceptives , and selective serotonin reuptake inhibitors [8, 9]. Nonpharmacological treatments are lifestyle interventions and cognitive behavioral therapy (CBT).
Overall, 75–85% of women have experienced PMS symptoms [1, 2] whereas PMDD affects 5–8% of reproductive age women worldwide . According to the International Classification of Diseases (ICD-10), only one distressing symptom at the time of menstruation is required for PMS diagnosis. It does not consider the severity of the symptoms, and no clear definition exists when PMS becomes clinically significant. Contrarily, diagnosis of PMDD mandates the impairment of functioning by the symptoms . According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) , the criteria for the diagnosis of PMDD are: (A) at least 5 symptoms must be present in the final week before the onset of menses and resolve within a few days of the onset of menses and these symptoms must occur in the majority of the menstrual cycles, (B) at least one symptom must be marked affective lability, marked irritability or anger or marked depressed mood or anxiety, (C) one or more of the following symptoms must be present: decreased interest in usual activities, difficulty in concentration, increased fatigue, change in appetite, marked change in sleep, feeling overwhelmed or physical symptoms, (D) these symptoms should affect productivity at work or school, relationships, responsibilities, and social activities. These symptoms should not be attributable/resultant to symptoms from (E) another psychiatric disorder or (F) physiological effects of a substance. Finally, (G) these symptoms should be confirmed by prospective daily ratings for at least two symptomatic cycles.
The Mini International Neuropsychiatric Interview (MINI) is a structured interview consisting of several modules to diagnose DSM-IV-TR psychiatric disorders [13–15]. Module U (MINI-U) is the corresponding module that measures categorically the presence or absence of symptoms to fulfill diagnostic criteria for PMDD . Prospective daily ratings have to be completed for at least two symptomatic cycles to confirm the diagnosis and are the only way to measure both severity and monitor symptoms over time .
The Premenstrual Symptoms Screening Tool (PSST) is an instrument that includes all premenstrual symptoms as well as a measure of impairment as per DSM-IV-TR criteria. It also translates categorical DSM-IV-TR criteria into a dimensional rating scale to assess severity . It is a useful diagnostic tool to capture moderate/severe PMS and PMDD diagnoses in symptomatic women who would benefit from treatment .
The MINI-U for diagnosis of PMDD relies mainly on the presence or absence of symptoms, including the impact on functioning, while PSST uses a dimensional scale to measure the severity of symptoms, which ultimately is very important to determine the effects of symptoms on daily activities. There are no studies that compared the diagnostic categorical scales with dimensional measures of severity of PMDD symptoms. Such comparisons would enhance the accuracy of the psychometric measures of the combined approaches when diagnosing and monitoring patients with moderate/severe PMS and PMDD. The availability of valid cut-off scores from PSST tested through answers from MINI-U (DSM criteria) would give more confidence to diagnose PMDD based on the severity measures of PSST. This reassurance would facilitate the initiation of treatment for this group of patients instead of waiting two months, especially that the daily recording of symptoms has proven to be very difficult in practice [19, 20]. Thus, the aims of this study are (1) to compare the responses between the dichotomous MINI-U answers and the scores on the PSST items; and (2) to establish the cut-off scores on the dimensional PSST items by using the categorical MINI-U as a gold standard.