Paxil Boosts Estrogen, May Promote Breast Cancer Growth


A trial of a new process of identifying drugs that can disrupt sex hormones singled out Paxil from 446 common drugs as having a weak estrogenic effect that could promote the growth of breast tumors in women. The study may shed light on previous studies that found women taking Paxil were more likely than those taking other antidepressants to die of breast cancer when also taking tamoxifen to prevent breast cancer recurrence.

Abstract →

Chen, S., Zhou, D., Hsin, L., Kanaya, N., et al; AroER Tri-Screen™ is a Biologically Relevant Assay for Endocrine Disrupting Chemicals Modulating the Activity of Aromatase and/or the Estrogen Receptor. Toxicological Sciences. Online February 4, 2014. doi: 10.1093/toxsci/kfu023

Of further interest:

Antidepressant Paxil boosts estrogen activity, new study finds (City of Hope)
New test suggests antidepressant Paxil may promote breast cancer (LA Times)
Popular antidepressant linked to increased breast cancer risk (RT)
Study: Paxil Could Promote Breast Tumor Growth In Women (CBS Atlanta)
Possible Link Between Paxil and Breast Cancer Found (Yakkity Yak)
City of Hope Researchers Develop Test to Assess Effect of More Than 1,500 Chemicals on Estrogen (Newswise)

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Kermit Cole
Kermit Cole, MFT, founding editor of Mad in America, works in Santa Fe, New Mexico as a couples and family therapist. Inspired by Open Dialogue, he works as part of a team and consults with couples and families that have members identified as patients. His work in residential treatment — largely with severely traumatized and/or "psychotic" clients — led to an appreciation of the power and beauty of systemic philosophy and practice, as the alternative to the prevailing focus on individual pathology. A former film-maker, he has undergraduate and master's degrees in psychology from Harvard University, as well as an MFT degree from the Council for Relationships in Philadelphia. He is a doctoral candidate with the Taos Institute and the Free University of Brussels. You can reach him at [email protected].


  1. Dr. Peter Breggin discovered a great deal about Paxil when he was an expert witness in a civil suit using discovery. However, the company settled out of court and the records were sealed. Thus, he can not talk about what he found out except to say it was not good. This was some years ago.
    It was in short like all the other nefarious concoctions. We have been told, and it seems reasonable to believe, that to become a doctor one needs to be extra smart and industrious. It is demanding mental and sometimes physical work. Thus at this late, very late date, one wonders why any doctor anywhere is handing out these products of medical quackery? Do doctors especially psychiatrists lose their ability to read? Not likely. Could there be the profit motive? One suspects as much. Being a psych doc can not be very demanding. You sit in an office knowing little about psychology or psychotherapy or apparently diet, listening to the patient as long as custom or habit deems necessary and then write out a prescription and bill the insurance company–thought that is done by an assistant.
    Experts in the medical world can pretend that the drugs are sometimes useful and just need more tweaking. Or better controls. Or something. Just so these profitable items are kept in circulation. Much like blood letting though perhaps worse in many cases.
    Who would dare label these august persons charlatans?
    Taking these eerie mixtures anything might happen. You have to wait and see. Years later you find out. Oh my God!! Why didn’t they tell me? Well, they probably did not know; but even if they had they would have kept it secret. Otherwise, profits down the drain. Do you remember why you took it in the first place? Not really. No. Just someone said it would help me. Did it? I don’t really know. Hmmm.

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