This paper reviews 3 recent studies from different clinics correlating psychotic symptoms with phases of the menstrual cycle in women with schizophrenia. The aim of the paper is to focus on the estrogen protection hypothesis which would suggest that low estrogen phases correlate with more severe symptoms, and high estrogen phases correlate with less severe symptoms. Although the methodology of the 3 studies was different, the hypothesis was essentially upheld. High levels of estrogens protect against symptom exacerbations in women with schizophrenia. A corollary to this finding is that, for optimal efficacy and safety, neuroleptic doses could be reduced at certain times of the month and increased at others.