There's the strangest feeling I come across from time to time, and I think "come across" is the only good way to describe it. Everyone has bouts of doubt and melancholy, I think or would like to think, but there's something much larger that creeps up that becomes harder to relate. In spite of the difficulty to describe, I could imagine anyone might feel this way, not just gifted children.
I always called it "The Cosmic Sadness", which is a name that I came up with after experiencing the feelings while I was reading about heat death of the universe (and associated articles) on Wikipedia[1]. This feeling ends up upsetting (not quite right, maybe disquieting) me much more than things like the death of a pet or a family member.
It doesn't only have to do with cosmological things, but I think it addresses the scope of the feeling, where you get this sensation of being so zoomed out, so encompassed by (perhaps) all that might be, that you have a hard time coming back down to being you.
It's like when you ponder the plight of some character in a novel you're reading, and you empathize enough to get a little upset, then you remember that none of that is real and its OK you've gone one level up now back to real life, no one is suffering like the character in the novel. You "snap out of it" - There's de-escalation, and some relief. But with the cosmic sadness there is no going up one level, it's all there to ponder and still real. No snapping out of it.
I was shocked by how this article ended because the only way of coping I have (other than mere time), to de-escalate this feeling, is literature and poetry. I tend to read several poems a day[2] as a kind of cathartic ritual, and poetry brings a comfortable way to remember (or re-realize) the very meaningful and concrete parts of experience, so I end up surrounding myself with it, finding the most comfort in it.
[1] http://en.wikipedia.org/wiki/Heat_death_of_the_universe
[2] For example Where to Live, by Du Fu: https://gist.github.com/simonsarris/5472121
Du Fu is a favorite of mine because he lived during a time that experienced one of the largest losses of human life on the planet (an lushan rebellion), so a lot of his poetry dithers between bleakness and hope. Somehow this makes it easy for me to reflect (perspective) and draw some inner sympathy for everything.