 New research suggests that one of the more popular antidepressants, Paxil, may actually contribute to the growth of cancerous tumors in women. That's according to a team of scientists from the City of Hope in Duarte, California, which has developed a quick way to zero in on drugs and chemicals that are capable of disrupting human sex hormones and influencing the development and progression of diseases, like breast cancer in women. As reported by the Los Angeles Times : In a trial screening of 446 drugs in wide circulation, the new assay singled out the popular antidepressant paroxetine (better known by its commercial name, Paxil) as having a weak estrogenic effect that could promote the development and growth of breast tumors in women. The finding is important because as much as 25 percent of women who are under treatment for breast cancer suffer from depression, and that's a condition regularly treated with antidepressants known as selective serotonin reuptake inhibitors, or SSRIs, like Paxil (which has been on the market for 22 years). Furthermore, the study showed, nearly a quarter of all women in the U.S. in their 40s and 50s are on some form of antidepressant, mostly SSRIs. Other medications also have a similar negative effect on estrogen The Times reported that, last summer, the U.S. Food and Drug Administration approved the marketing of a low-dose paroxetine, which has been repackaged under the trade name Brisdelle, as a treatment for hot flashes and other menopause-related problems that is also non-hormonal. Some 70 percent of breast cancers in women are estrogen-sensitive, which means that a hormone found in abundance in childbearing-aged females actually contributes to the growth of cancerous tumors. The unique screening method that was developed at City of Hope, which was detailed in an upcoming issue of the journal Toxicological Sciences , also identified a pair of antifungal drugs -- biconazole and oxyconazole -- as having a negative effect on estrogen that was similar to that of medications prescribed to prevent breast cancer and stop it from recurring in women. More from the Times : Incidental to their intended use in combating fungal infections, those medications inhibit the action of aromatase, an enzyme that converts androgens -- hormones more plentiful in males but present in both sexes -- into estrogen. Less surprising, the high-throughput screening mechanism identified bisphenol A -- a compound used in the manufacture of plastics and epoxy resins -- as an estrogen promoter capable of raising breast cancer risk. The finding that Paxil has an endocrine-altering effect may provide insight to cancer researchers regarding their increased suspicions of medication in women with breast cancer. In 2010, for example, a study found that breast cancer patients in Canada who were prescribed Paxil were more likely than those who had been given a different antidepressant to die of breast cancer, 'when there was a substantial overlap in their use of that antidepressant and of tamoxifen to prevent breast cancer recurrence,' the Times reported. The researchers believed that paroxetine -- taken by about one-fourth of cancer patients in the study who had been diagnosed with depression -- might block the production of a liver enzyme that scientists say is necessary to break down tamoxifen. The authors of this latest study said that paroxetine's 'weak estrogenic' effect 'may be responsible, in part, for the observed reduction' in tamoxifen's effectiveness in the study. As a class of drugs, SSRIs have proven to be quite controversial, as we have documented for years here at selfnews . Among the most controversial: -- SSRIs have been linked to birth defects, complications during pregnancy and even miscarriages. 'Big Pharma wants pregnant women to take prescription drugs, vaccine shots and even chemotherapy. It's the latest insanity from an industry that kills more Americans ever year than died in the entire Vietnam War. And the latest science reveals that antidepressant use during pregnancy is causing babies to be born with physical defects -- or sometimes not born at all because they're miscarried' [ http://www.selfnews.com ]. -- Studies have shown that women who take SSRIs during pregnancy run a higher risk of developing pulmonary persistent hypertension (high blood pressure) [ http://www.selfnews.com ]. -- And there is this: Studies suggest that SSRIs -- which are prescribed ostensibly to 'treat' depression -- may lead to more suicides among patients taking them [ http://www.selfnews.com ]. Sources: http://www.latimes.com http://www.selfnews.com http://science.selfnews.com 