I don't believe it, but of course that is what they would say. Nymag.com is reporting that Christophe's people said this:
“He has been exhausted because this season was particularly demanding and complicated. “The spokesperson says that the rumors about a breakdown from drugs and the mental hospital are “completely untrue.” The spokesperson wouldn’t say the cause of his ailment, only that it was “not anything physical.”
No shit they are going to deny it. Do I believe it? No. What was so complicated about this collection? If anything it was less than expected of him. I just hope he's okay!