Theodore Clay was commited to Eastern State Hospital in 1833. His occupation was a lawyer.

The Cincinnati "Enquirer" of the 19th inst., comments as follows on the announcement of the death of Theodore, eldest son of Henry Clay, in the Lexington (Ky.) Lunatic Asylum, after a long confinement:
At thirty years of age Theodore Clay was a promising lawyer. He was the image and the hope of the Statesman whose fame was on every tongue. It is true there were whispers of wild living or indifferent morals, that somewhat tinged his fair repute, and even darkened his future prospects. Still it was hoped that these were but the result of youth, and would be set aside when circumstances called upon the natural man to assert himself and make his talent felt in the community.
It was at this turning point in his life that Theodore Clay began to pursue , with an unwearied perseverance that caused his friends great uneasiness, a young lady of Lexington, whom he had long loved hopelessly. The object of his attachment, who is at present one of the brightest ornaments of Kentucky society, repulsed firmly, but kindly, every attention offered by the infatuated young man, after his meaning had become manifest. It were useless: he would not be refused, and followed her in the streets by day, and wandered in the neighborhood of her home by night, in an annoying manner, until at last it became evident that he "was not all there." to use the soft phrase by which a kindly peasantry express insanity. Subsequent violent demonstrations tended to confirm the impression, it being even related that he went to the house of Mr. _____ and demanded his daughter at the pistol's point, until at last the wretched truth could no longer be ignored and confinement in the Asylum became a necessity. This was accordingly done (in 1832 we believe), his father providing for his support at that time, and leaving $10,000 in his will, the income from which was secured to Theodore for life. That life, after thirty-eight years of imprisonment, in what in the earlier days of his confinement he was wont to call "a good boarding house, but having some of the biggest fools he ever saw as boarders," has just closed. For nearly thirty years he was one of the most noted of the inmates, not only his proud descent, but his graceful manners and flow of conversation rendering him an object of interest to all visitors. He labored under the hallucination that he was George Washington, and was fond of assuming the traditional attitude of the Father of his Country. At the occasional balls given to the inmates (averaging some 500 in number) he was always beau par excellence.—During all these long years, despite his general gentleness and cheerfulness of manner, he was restless and discontented, and required close watching, it never, in fact having been considered prudent to allow him to go out on the grounds without attendants. About the year 1869, his condition began to grow worse, and he soon after became demented, continuing in hopeless idiocy until a few days since, when Death, greater healer than Time, placed him again upon an equality with the peers of his early manhood who had gone before him to the God that created him and did with him according to His inscrutable will. And so ends as sad a story as the truth of history ever commanded to be written.
Two sons of Henry Clay yet survive him—T.H. Clay, ex-minister to Honduras, now residing on his place, "Mansfield," near Lexington, and John M. Clay, the raiser of "Kentucky," and one of the greatest turfmen living.
Source: The Farmer's Cabinet, Amherst, New Hampshire, 26 May 1870; This Obit was found by Pam Brinegar

Theodore Clay was buried in the Lexington Cemetery on May 5, 1870 in Section: I, Lot: 38.