Estradiol as add-on to Antipsychotics

Several lines of evidence suggest that estrogen affects the course of schizophrenia. The onset of schizophrenia is 2-4 years later in women than in men, and women have a lower incidence of schizophrenia until menopause, after which women have an increased incidence, so that the lifetime prevalence is similar in both genders. Women are more likely to have their first schizophrenic episode during an estradiol trough in the menstrual cycle. These gender differences in the natural course of schizophrenia are well replicated and provide a major lead to understanding and treating the illness, and have led to several randomized controlled trials administering oral estradiol to patients with schizophrenia. Studies on transdermal estradiol have been more encouraging, and four RCTs, have shown that estradiol patches are efficacious in treating schizophrenia The most recent study was performed our group and showed that overall estradiol patches were efficacious with an effect size of 0.41 for total PANSS, with significant improvements in PANSS positive, negative and general-psychopathology scores. Post hoc analyses showed that the improvements in symptoms were found almost exclusively in women who were 38 and older, in whom the effect of estrogen patches vs placebo reached an effect size of 0.58 for PANSS total. The currently proposed study is based on the post-hoc finding of improvement in participants aged 38 and above, and we will a-priori recruit women with schizophrenia 38 and above, in order to test the efficacy of 200 µg estradiol patches vs placebo in these woman.