I've not had time yet to find the very detailed letter referred to in the previous Tamoxifen post. However I know the main problem with trying to pin down whether Tamoxifen can have adverse effects in the brain. It definitely crosses the blood/brain barrier. But the complication is that sometimes Tamoxifen acts like Oestrogen and sometimes it acts as an anti-Oestrogen. Its anti-Oestrogen manifestation is what makes it useful in relation to breast cancer, or at least in those breast cancers where Oestrogen plays a part.
It is unclear which effect Tamoxifen might have when it reaches the brain. A further complication is that it is unclear whether Oestrogen itself is beneficial or harmful to the brain; the research gives contradictory results. Unsurprisingly, in these circumstances, the small amount of research that has been done to try and determine whether Tamoxifen is good or bad for the brain is also inconclusive.
So someone like S who, on medical advice, was simultaneously taking Oestrogen (HRT) and Tamoxifen could have been adversely affected by either or both Or presumably the effects could have cancelled each other out, or they could both have had a beneficial effect. And her condition might have nothing to do with either of them!
It interests me that American scientists wanting to degrade the memories of mice used Tamoxifen to do so. These were 'transgenic mice' that had had their genes interfered with to enable this 'unusual' response to Tamoxifen. But this surely raises the possibility that humans with a particular genetic make-up could be similarly affected by Tamoxifen?
It is amazing to me that these scientists already knew about a link between Tamoxifen and memory yet no-one researching memory problems in humans seems to have made such a connection.
I will find the link to the report and post it here.