Assessment of premenstrual symptoms: validation of the Italian version of the Premenstrual Symptoms Screening Tool.

Abstract

The aim of this study was to provide an Italian validation of the Premenstrual Symptoms Screening Tool (PSST). The PSST is a retrospective questionnaire, originally developed in English language, used for the screening of Premenstrual Syndrome (PMS) and of Premenstrual Dysphoric Disorder (PMDD). PMDD and PMS are common, but are often not adequately recognized and treated, although they can heavily interfere on women's quality of life. An Italian version of the PSST from English was prepared using the "forward-backward" procedure, and submitted to a sample of 520 women over 18 years of age (mean age of 23.6; DS=±3.1). The content validity, the internal consistency, the test-retest reliability, and the convergent validity were evaluated. The factorial structure underlying the questionnaire was assessed with the use of both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). Among the 520 participants to the study, 337 experienced no or mild premenstrual symptoms (64.8%), while 158 women evidenced a positive screening for moderate or severe PMS (30.4%), and 23 for PMDD (4.4%). The Italian PSST displayed adequate content validity and a very good internal consistency, with a Cronbach's alpha of 0.89. The test-retest reliability showed satisfactory results, with a Spearman's ρ for the overall score of 0.80, and the intra-class correlation coefficient (ICC) of 0.810 (95% CI=0.761-0.862; p<0.001). The EFA was performed using the principal component analysis, followed by varimax rotation. The CFA was conducted on EFA results and supported a four-factor model, yielding the best fit indices [χ2/df=1.76; CFI=0.920; TLI=0.904; RMSEA=0.054 (0.043-0.065)]. The convergent validity, evaluated using the Spearman's correlation coefficient between the overall score of the Italian version of PSST and the Beck Depression Inventory (BDI) score showed a good value (ρ=0.647 p<0.001). Our results support the cross-cultural validity of the questionnaire, suggesting that the Italian version is a reliable and valid tool, as well as easy to use, to screen women in need of treatment for their premenstrual symptoms.