According to a new study on the safety of antipsychotic medications, the use of dopamine antagonists is associated with an increased risk of breast cancer. Published in this month's issue of Archives of General Psychiatry, the study, conducted by researchers from Brigham and Women's Hospital in Boston, analyzed more than 100,000 women, half of whom used a dopamine antagonist between January 1, 1989 and June 30, 1995.

Patients who took an antipsychotic dopamine antagonist were found to be 16 percent more likely to develop breast cancer than those unexposed to the medications. Research indicated that the drugs increased prolactin levels in women, a side effect that has been linked to the development of breast cancer.