Abstract Contingent negative variation (CNV), postimperative variation (PIV) and reaction time (RT) were recorded in a signalled Go/No Go avoidance paradigm, verbal and visuo-spatial versions of a match/mismatch paradigm, and an auditory forewarned RT paradigm at 3 menstrual cycle phases—menstrual, mid-cycle and premenstrual—in 3 samples of women: women without significant premenstrual changes (PMCs) in mood and behaviour; women with documented PMCs in mood and behaviour excluding premenstrual impulsivity; and women with documented PMCs in mood and behaviour including changes in impulsive behaviour. Subjective stress and arousal were also measured at each cycle phase. Recordings were repeated in a small sample of women with PMCs during treatment with fluoxetine/ placebo. There was no relationship between either state or trait measures of impulsivity and Go/No Go CNV, in contrast with previous findings in males. MANOVA revealed significant Group × Phase interactions for early CNV amplitude and laterality in the forewarned RT paradigm, and for subjective stress, supporting a “disordered state regulation” hypothesis of premenstrual syndrome (PMS). Other measures (subjective arousal, PIV in the Go/No Go paradigm) showed significant effects of Group independent of cycle phase, with PMS groups showing lower arousal and greater postimperative positivity than controls.