The main difficulty would lie in knowing where to draw the lines. Do you include any sort of agitated response to any sort of idea that isn't of immediate practical relevance to daily life?
I would draw the line at regular obsessions, mostly because cognitive behavioural therapy at least offer some options. I have some experience with obsessions, and those were self contained, situationally. Not a personal example, but a pre-occupation with staying away from sharp objects for fear of committing suicide, despite not having depression or violent impulses, is local to that situation of being around sharp objects, not triggered by simply thinking about sharp objects in a room completely devoid of sharp objects.
Anything within the line would be subjects whose trigger is their being facts, whose consequences are reacted to quite quickly, and are not specific to any physical situation a person may be in at the time. I'm not so sure about Pascal (based on that sentence alone I mean), but Everett's daughter would fit the bill, assuming her belief compelled her to commit suicide, rather than gave her freedom to do it. I recall one person who actually had a similar problem here at Lesswrong, not two months ago actually. I'm surprised that I forgot about it. I guess I would call these "abstract obsessions" as opposed to "personal obsessions".
I apologize for not fleshing this out in better detail in the original post; I wasn't expecting this to generate interest from anywhere outside the hypothetical target audience, though in retrospect, I would probably have dug into it too.
EDIT: I'm reading the transcription of XiXiDu's psychology session, and this looks exactly like the class of problem I'm talking about.
As some of us might be aware, there exist ideas that harm their carriers simply by lingering in awareness. One may wonder if these ideas are just manifestations of Obsessive Compulsive Disorder or other neurosis, but the difference here is the metaphysical nature of such ideas.
A person with OCD may have their thought stream painfully interrupted by whatever's been fixated upon and literally be unable to stop. I conjecture that a person who has a form of metaphysical obsession will have their thought stream *infected*, such that anything they value or care about will be permanently devalued somehow, rather than being merely pushed away, or that the subject of obsession will be *compatible* or *miscible* with ones ordinary life and that one will make logical inferences about one's life based on those metaphysical ideas. The difference between this and regular personal development is that these inferences don't make one come up with useful ideas or insights for improvement; rather than supplementing one's life, they *deconstruct* and *disassemble*, by virtue of their global scope. I'll elaborate more on this in the last paragraph.
I further conjecture that anybody with these dangerous ideas would avoid telling anyone else out of remarkable conscience, under the belief that these ideas are unresolvable and would simply harm others. Alternatively, they may see these ideas as a revelation and try telling others, only to not be taken seriously. In defense of this article from those in the former category, I'll present no such ideas, because I'm not a complete dumbass. What I'm presenting is an opportunity.
Anyone who has these ideas shouldn't post them here; this article is just to gauge interest in/need for a group which shares their ideas knowing that:
A) Different perspectives help
B) Those with whom you're sharing aren't going to feel significantly worse for the burden
C) If a solution isn't found, *other* people are going to come up with them, so we might as well get it over with and post the solutions.
One may wonder how dangerous ideas could possibly exist, or think that these are just misunderstood epiphanies. To them I ask to read about George Price, the population geneticist, journalist and chemist, whose work on the origins of altruism drove him first to give away all his possessions, then to let the homeless sleep in his house. These are all *really* generous things, but I feel that the mindset of Price when doing these things was tainted by *desperation*, that he wanted to avoid a terrifying conclusion, namely that selflessness itself was rooted in selfishness, making its goodness non-intrinsic. The paradox seems easy to resolve on the outside, when one isn't panicking about it, and while working through a similar crisis I kind of wished I could go back and time and explain to him why interpretations like that are only *half* the story. He cut his own throat with a pair of scissors at the age of 52.
[Edited out some poorly received theatrics, which admittedly bordered on the unnecessary]