Doh. Maybe I'm too tired so my brain is working less well than I'd hope, but I hadn't noticed the link to the Bostrom paper there. I need to try to more carefully read through the stuff people say to me.

I'll give the paper a read-through tomorrow.

[edit] I scanned the paper, but the tiny section on neuropsychological hazard seemed to tend toward the low-level (photosensitive epilepsy as one example), rather than the Lovecraftian (as I might have expected it to, if I had thought carefully about it, since I don't place much credence in high-level ideas that could blow your mind that way)