I think one has to give one's definition of giftedness to make one's case either way, even though there is no official definition so the next person might define it in a way that did not match the statistics that the first offered.

This article: http://www.psychologytoday.com/blog/...ental-disorder makes the case that it goes all ways for children; there are those who are misdiagnosed as having a mental disorder and those who do have a mental disorder that is not diagnosed and those that aren't identified as either, when they are one or the other or both.