Abstract
PURPOSE: To assess the validity and reliability of the Japanese version of the Daily Record of Severity of Problems (J-DRSP, 24 items) for evaluating symptoms of premenstrual syndrome (PMS), and to develop a short form version of the J-DRSP. METHODS: Using the "DRSP-JAPAN" smartphone app, we collected daily J-DRSP records from cycle day - 6 (CD - 6) to CD 10, with CD 1 representing the menstruation onset date. Factorial validity (exploratory factor analysis: EFA, confirmatory factor analysis: CFA) and criterion validity were examined, and test-retest reliability (intraclass correlation: ICC) evaluated. The short-form version of the J-DRSP was developed using classical test theory. RESULTS: In total, 304 women participated and 243 recorded symptoms on at least 4 days spanning the week of the luteal phase (CD - 6 to CD 0) and 4 days spanning the week of the follicular phase (CD 4 to CD 10), with CD 0 set as the day before menstruation started. The EFA revealed a two-factor structure. Kaiser-Meyer-Olkin was 0.992, and Bartlett's test of sphericity chi-square was 3653.89 (P < 0.001). However, the model fitness of CFA was found to be suboptimal (comparative fit index (CFI): 0.83, root mean square error of approximation (RMSEA): 0.12). Total scores for J-DRSP and the sum scores for each subscale were higher on CD 0 than on CD 10 (p < 0.001), suggesting validity for some criteria. ICC values for the total J-DRSP score from CD 0 to CD - 1, and between CD 9 to CD 10, were 0.60 (95% CI: 0.48-0.72) and 0.76 (95% CI: 0.69-0.82), respectively. Having eliminated some original items after considering factor loading for each item, we developed an 8-item Short-Form J-DRSP (J-DRSP (SF)) comprising 2 factors (S-Psychological and S-Physical, 4 items for each). CFA showed a better model fit (CFI: 0.99, RMSEA: 0.048), and ICC values in the luteal and follicular phases were 0.61 (95%CI: 0.51-0.68) and 0.70 (95%CI: 0.62-0.77), respectively. CONCLUSION: The J-DRSP has moderate to good reliability and a certain level of validity. The 8-item J-DRSP (SF) has a two-factor structure and can be used effectively among Japanese women to assess their PMS symptoms.