A study, by researchers of the Harvard Medical School, of more than 100,000 women, indicates that women who use dopamine antagonists, i.e. anti-psychotics, for either psychiatric illnesses or other conditions, may have an increased risk of breast cancer.
The study involved about 52,000 women who were taking dopamine antagonists and 55,000 women who were not. The two groups were compared for breast cancer rates. It was found that women who were on anti-psychotics had about a 16 per cent increased risk of breast cancer and those who took larger doses of the drugs had a greater risk.
The researchers believe that the study is significant because more number of women, world over, are being affected by breast cancer and understanding risk factors for the disease is paramount to controlling its incidence. Animal studies have suggested dopamine antagonists can raise blood levels of prolactin, which has been shown to promote tumor growth in rats. However, studies linking the drugs and breast cancer in women have been limited and researchers say that further studies are needed before changing treatment strategies for women taking anti-psychotics.