This is the earliest mention of Huxley I've found, and it's sort of second-hand.

The Christian Century
Volume 45
1928
Pg. 823:
The realistic literary school of our day focusing its gaze on the sordid side of human nature, expresses, through a spokesman, Mr. Aldous Huxley, its conviction by saying, “Ye shall know the truth and the truth shall make you mad.”

Herman Melville, Mariner and Mystic
By Raymond Melbourne Weaver
New York, NY: George H. Doran Company
1921
Pg. 26:
Thou shalt know the truth, and the truth shall make you mad. To the eye of truth, so Melville would convince us, “the palsied universe lies before us as a leper;” “all deified Nature absolutely paints like a harlot, whose allurements cover nothing but the charnal house within.”