he was first in line. >> safer: what exactly was tormenting vincent van gogh? fers a clue-- the ear incident. in 1888, vincent found what he thought was a kindred spirit, fellow painter paul gauguin. for two months, they shared the famous yellow house in the southern french city of arles. why did gauguin join with him in the first place? >> naifeh: money. very simply, money. theo was basically buying him as company for vincent. >> safer: van gogh painted gauguin at work. gauguin painted van gogh, but found vincent's craziness impossible to live with. they argued bitterly and gauguin left. what followed was a major psychotic episode. did he cut the entire ear off or the lobe or what? >> naifeh: there was some dispute about that. it appears that he cut off more than the lobe, but less than the entire ear. and it was a disturbing sight, even after it healed. >> safer: in the hospital, vincent was treated by a young intern named felix rey, who then spent months trying to diagnose his mental condition. though doctors have debated the matter for a century, naifeh and