This is a bit of a ramble...
Well, I'm supposed to be "gifted" myself, and I'm fairly normal– I hope! (I did play up in school because I was bored, though.)
Which perhaps answers my question, but I'll get to that.
In fact, there's been a lot of research done on gifted children and adults which shows they're mostly psychologically healthy– the "crazy and maladjusted" thing is largely a stereotype, and where it does occur, more due to the way other people treat them.
There's another thing, though. I believe we tend to hear so much more about disturbed geniuses, because, well, they're a bit more palatable to the general public.
Sooo... that's one way a society might deal with having magic-users, telepaths etc. among them.
Instead of having mages vs commoners or everyone yelling "burn the witch", you'd get a bit of very low-key social prejudice. People would be just slightly unwilling to admit to being telepaths or whatever because everyone "knows" they're all weirdos.
I am, of course, drawing on my reluctance to show off my 133t Mental Skillz!111! for fear of "Rain Man" jokes. Hey, it actually never occurred to me that I could use my own experiences!
I'm still not sure that's the same as having an ability different in kind from others', and inaccessible to them (I don't believe intelligence is nearly as fixed as some would have it).