Women with schizophrenia who take first-generation antipsychotics such as Risperdal had a higher risk for breast cancer compared to women who did not take antipsychotics as well as women taking second-generation antipsychotics, according to a study published in the journal Schizophrenia Research.
The study, conducted by researchers with China Medical University in Taichung, Taiwan, focused on whether schizophrenic women were more prone to breast cancer diagnoses compared to women who did not have the disease. They reviewed health insurance claims data from 1998 to 2008 and compared records of 29,461 women with schizophrenia with 59,282 women who did not have a serious mental illness and who were not taking antipsychotics. They found that women with schizophrenia had a twofold increased risk of breast cancer compared to their study counterparts.
The researchers also noted that some antipsychotic drugs could increase prolactin levels because they block dopamine-2 receptors. Prolactin is the hormone that triggers breast growth and lactation in pregnant women.
With this in mind, researchers stratified patients by subgroups, singling out women who were taking antipsychotics with prolactin-elevating properties. They found that women who were taking Risperdal (known generically as risperidone) or similar antipsychotics that increased prolactin levels had a higher risk for breast cancer compared to those who were not taking antipsychotics.
Risperdal is also used to treat children with schizophrenia and can cause spikes in prolactin in adolescent boys, which can trigger breast growth and lactation, a condition called gynecomastia. Johnson & Johnson and its subsidiary Janssen Pharmaceuticals are facing thousands of lawsuits alleging the companies knew the drug could cause boys and young men to develop disfiguring breasts but did not adequately warn the public.