Since part of Raloxifene's mechanism of action involves activating the estrogenic receptors, some studies have explored the possibility that polymorphisms in these alfa (ESR1) or beta (ESR2) estrogenic receptor genes can modify the effects of treatment with raloxifene(29-31). Several pharmacogenomic studies have reported that single nucleotide polymorphisms (SNPs) in these genes, affect raloxifene treatment in relation to its endothelial function(29), cholesterol levels(30) and bone mineral density(31). Nevertheless, no studies have assessed whether these SNPs of ESR1 or ESR2 can influence raloxifene's effects in the brain. Based on the positive results of our preliminary study, we have designed a longer clinical trial with the same dose of raloxifene that had been effective in the first study. We aim to include in this 6-month placebo-controlled, randomized, double-blind clinical trial a larger number of post-menopausal women with schizophrenia, and improve the clinical assessments by using a larger battery of psychometric tests in areas of social functioning and neuropsychological performance. Genotypic studies will be conducted of the 4 SNPs in the ESR1 (rs9340799, rs2234693, rs1801132) and ESR2 (rs1256049) genes, to control the effects of patients' genotypes on response to treatment.