* Ewan McGregor as Alan
* Stephen Root as Matthew
* Mamie Gummer as Emily
* Olivia Thirlby as Sarah
* Patrick Fischler as Josh
* J.K. Simmons as Dr. David
* Anthony Mackie as Quentin
* Josh Pais as Ted
* James McCaffrey as The Lawyer
* Annabella Sciorra as Anna
* Michael O'Keefe as Sam
* Aisha Tyler as Dr. Anna
* Rob Huebel as Brian
* David Rasche as Art Dealer
* Amanda Warren as Woman at Dinner
* Richard Kind as Dr. Peter
* Josh Hamilton as Jeff
* John Ventimiglia as John
* Rebecca Henderson as Nurse
* David Zayas as Manny
* T.J. Thyne as Alex
This list includes the main cast and recurring actors.