He went insane when he was about twenty, and spent the rest of his life at the private asylum at Greatford, Lincolnshire, which had been founded by the renowned physician Francis Willis.
[note 1] He was elected to the Irish House of Commons as member for Queen's County in 1790,[3] but unseated the following year on foot of[clarification needed] a petition that he was disqualified by reason of insanity.
[citation needed] When he was about the age of twenty he began to show signs of mental illness, which may have been hereditary.
Willis had won renown in 1789 for curing King George III of what was thought then to be insanity but is now generally agreed to have been porphyria.
[6] Lord Castlereagh, who committed suicide in 1822, was Lord Drogheda's first cousin and the increasingly strange behaviour which culminated in his death was thought by some to be due to a hereditary mental illness inherited from the Seymour Conway family, to which his mother, as well as Drogheda's, belonged.