Analyze That Screenplay

Mob boss Paul Vitti (Robert De Niro) is nearing the end of his term in Sing Sing, and the FBI agents monitoring him are baffled. Day after day they watch as New York's most notorious gangland figure walks around his cell in a semi-catatonic stupor. Is Vitti having a nervous breakdown because of recent threats on his life or is his odd behavior merely a foxy ploy to get him sprung from jail early?