The discovery that estrogen has a modulatory effect on the dopaminergic system has encouraged some researchers to study the therapeutic use of estrogen in schizophrenic patients. Several double-blind clinical trials have shown that estrogens are effective at improving psychotic symptoms(13-15). These last studies analyzed the efficacy of estrogens after one and two months, and mainly in relation to positive symptoms, in patients with the acute illness. However, in older patients it is the severity of the negative, rather than the positive, symptoms that seems to be associated with a poorer cognitive and social function. Moreover, positive symptoms tend to be less severe with age, while negative symptoms tend to persist(16).