The Singing Detective (2003)

Robert Downey Jr. stars as Dan Dark, a bedridden crime novelist writing about a private investigator who doubles as a singer in a dance band. The detective is slowly drawn into a web of intrigue during the murder investigation of a prostitute. Heavily medicated, the border between reality and fiction starts to blur in Dark's mind. The plot is woven together with his own childhood memories, and soon he is living in a fevered film-noir hell constructed by his own twisted psyche, where everyone is his enemy and no one can be trusted. Mel Gibson co-stars as the enigmatic Dr. Gibbon, the hospital psychiatrist who dares to take on Dark's tortured mind.