Totally crazy, as in The constant uncertainty over his job is making him stark raving mad. This term, meaning “completely wildly insane,” is used both hyperbolically and literally. Versions of this expression appear to have sprung from the minds of great literary figures.
Stark mad was first recorded by poet John Skelton in 1489; stark raving was first recorded by playwright John Beaumont in 1648; stark staring mad was first used by John Dryden in 1693. The current wording, stark raving mad, first appeared in Henry Fielding's The Intriguing Chambermaid in 1734.