Recent research has increasingly pointed to the importance of estrogens and the hypothalamic-pituitary-gonadal axis in schizophrenia. Specifically, there is mounting evidence from clinical, epidemiological, and basic research that estradiol, the main component of estrogens, exerts protective effects in schizophrenia and related psychoses. Possible modes of action of this hormone in the brain have been suggested, and clinical intervention studies have reported the first positive results. Furthermore, there are an increasing number of reports on gonadal dysfunction and states of estrogen deficiency in women with schizophrenia. These findings could have important implications for clinicians and researchers alike. ? Springer-Verlag Berlin Heidelberg 2011.