IIRC, allegedly there were a few people with OCD having nightmares after reading that post by Roko.
My point was that it doesn't cause mental health problems, not that it can't trigger them. Perhaps that's a bad way to put it. If it does, there's something beyond the information hazard going on, either an existing problem being triggered, or a multiple hazard. As I understand it, a basilisk is hazardous because you know the argument, without it needing to corrupt your reasoning abilities. Roko's is alleged to be hazardous even to a rational agent. (I don't think it is, and I think censoring it prevents an interesting debate about why. I don't plan to say any more, given the existing censorship policies. If this is already too much, please let me know and I will edit accordingly.)
http://wiki.lesswrong.com/wiki/Deletion_policy
This is my attempt to codify the informal rules I've been working by.
I'll leave this post up for a bit, but strongly suspect that it will have to be deleted not too long thereafter. I haven't been particularly encouraged to try responding to comments, either. Nonetheless, if there's something I missed, let me know.