It's quite possible that Ezra Pound was not actually insane; rather, he just didn't want to stand trial for treason.
American poet Ezra Pound is well known for leaving an indelible mark on modern poetry, but you may not know he was also a controversial political creature. Pound admired fascist dictator Benito Mussolini, and moved to Italy in 1925 where he began writing and broadcasting pro-fascist, anti-Semitic, anti-Roosevelt radio commentaries during WWII. The American government considered this an act of treason, and Pound was arrested and imprisoned in Italy after the end of war.
After Mussolini's death, Pound was extradited to the U.S., facing charges that he aided American enemies during WWII. He pleaded insanity, was found not to be competent to stand trial, and was hospitalized at St. Elizabeth's in Washington, D.C. where he remained until 1958.
Pound may have been a narcissistic fellow, but whether or not he was insane is still debated today -- new documentation has scholars and mental health professionals pointing fingers at the abuse of the psychiatric system and the power of his literary friends for enabling Pound to skirt being tried for treason.