The plot of inmates taking over the asylum and impersonating the warden closely resembles Dagger of the Mind (1966), right down to the "agony chair" prop which is reused from that episode. In his memoir 'I Am Not Spock', Leonard Nimoy shares a memo that he wrote to the producers to complain about the similarities.
The episode's title is often misattributed to the Greek playwright Euripides. However, the phrase "Whom the gods would destroy, they first make mad" is spoken by Prometheus in Henry Wadsworth Longfellow's poem "The Masque of Pandora" (1875). Another version ("Those whom the gods wish to destroy they first make mad") is quoted as a "heathen proverb" in 'Daniel, a Model for Young Men' (1854) by William Anderson Scott (1813-1885). Yet another variation on the phrase was given by historian Charles A. Beard, who, when asked to write a short volume summarizing the lessons of history, said that he could do it in four sentences. One of them was, "Whom the gods would destroy, they first make mad with power."
Garth's torture chair is a reuse of the chair in the neural neutralizer room from Dagger of the Mind (1966), with the addition of earpieces mounted on either side.
The asylum planet's name is based upon an historical place. Elba II is named after the Mediterranean island off of the coast of Italy where the French Emperor Napoléon Bonaparte was briefly exiled to in 1814. Napoleon succeeded in escaping from there in 1815 and was restored to power in France, but was later defeated at Waterloo. He then spent the remaining six years of his life on the remote South Atlantic island of Saint Helena. "Captain Garth" in this story was characterized as another Napoleon.