The relationship between female sex steroids and mental disorders was not thoroughly studied until the last decades. However in recent years, many studies have appeared that evaluate the influence of estrogens on the onset, outcome and treatment of mental disorders. Although the data are still preliminary, it could be concluded that the estrogens can be useful in the treatment of postpartum depression and menopause related depression, especially if surgically induced. There is still no support for the usefulness of estrogen treatment in non-reproductive related mood disorders. Regarding its utility in schizophrenia, several studies have considered the possibility of adding estrogen treatment in the cases in which patients with schizophrenia experience a worsening of their symptoms clearly related with the fluctuations of the hormonal levels during the menstrual cycle or in patients with resistant forms of the illness. Furthermore, hormone replacement therapy could be useful in some postmenopausal schizophrenic women.