3.The severity of premenstrual symptoms was measured using the Shortened Premenstrual Assessment Form (SPAF) (Allen et al. 1991). The SPAF is composed of a 10-item retrospective measure designed to measure changes in mood, behaviour and physical condition during the premenstrual period within the last three premenstrual periods. Women were asked to rate the severity of change in symptoms on a scale of 1–6 (1 = no change at all to 6 = extreme change) during the premenstrual period. The SPAF allows assessment of three PMS factors (negative affective, water retention and pain) that occur in the 7 days prior to the onset of menses, compared with the non-premenstrual state. Items were summed to provide the SPAF score. The higher the total scores on SPAF, the more severe the premenstrual symptoms. The SPAF was found to be reliable (Cronbach's alpha 0.80) and valid (Allen et al. 1991, Thu et al. 2006). In this particular sample; Cronbach's alpha for SPAF was 0.88