Who sang the song 'Mad World'?

Tears for Fears co-member Roland Orzabal wrote and sang Mad World on their first album, The Hurting, released in 1983. Another version was done by Gary Jules for "The Shield" a TV drama series. More recently, it was sung by Adam Lambert, on American Idol, season 8, April 2009. A version was also performed by Aiden Grimshaw on the UK show 'X Factor' in the first live show of 2010.