Elevations of complex partial epileptic-like experiences during increased geomagnetic activity for women reporting "premenstrual syndrome".

Responses to the frequency of complex partial epileptic-like experiences were recorded every second day by 12 women for at least two months per individual. Five (41%) of the women displayed significant increases (effect sizes between 6% and 17%) in the numbers of these experiences when the daily geomagnetic activity exceeded 40 nT. The results were consistent with the hypothesis that a spectrum of experiences and behaviours, associated with limbic lability, can be enhanced by environmental stimuli correlated with perturbations of the geomagnetic field.