Alan Arkin as Simon Mendelssohn

Madeline Kahn as Dr. Cynthia Mallory

William Finley as Fichandler

Wallace Shawn as Eric Van Dongen

Max Wright as Leon Hundertwasser

Fred Gwynne as Maj. Gen. Korey

Austin Pendleton as Dr. Carl Becker

Judy Graubart as Lisa

Adolph Green as Commune Leader

Keith Szarabajka as Josh

Ann Risley as Pam

David Susskind as Himself

Dick Cavett as Himself

Billie Perkins as Commune Member

Jayant as Barundi

Pierre Epstein as Military Aide

Roy Cooper as General's Aide

Rex Robbins as Army Doctor

David Warrilow as Blades

David Gideon as Security Guard

Hetty Galen as Simon's Mother (voice)

Remak Ramsay as TV Newscaster

Hansford Rowe as Priest Babcock Beastly

Yusef Bulos as Hemling Grotowsky

Jerry Mayer as Prof. Jerry Milstein

Sol Frieder as Rabbi Chaim Glassberg

William Griffis as Senator

Frank J. Lucas as Psychologist

George Riddle as Muttonchop Aide

Tom Kubiak as Roach Reaction Patient

Al Cerullo as Helicopter Pilot

Barbara Mongin as Institute Staff Member

Paula Gibson as Melody

James Dukas as Narrator (voice)

Jim Saxon as Commune Member

Michael Earl as Commune Member

Jay Lowman as Commune Member

Steven Nash as Commune Member

Barbara Bergen as Commune Member

Joyce Adams as Commune Member

Bonnie Deroski as Commune Member

Kathryn Cordes as Commune Member

Leslie Frances Williams as Commune Member

Nick Pippin as Commune Member

Ed Karvoski as Commune Member

Mary Lou Kleinbach as Commune Member

Richard Bassett as Commune Member

Phil Witt as Commune Member

Isam Culver as Commune Member

Rickey Murray as Commune Member

Stephanie Segal as Commune Member

Max Goff as Commune Member

Mary Donnet as Commune Member

Don Stitt as Commune Member

Nikki Kollins as Commune Member

Jenny Gault as Commune Member

Regina Rodwell as Commune Member

Schorling Schneider as Commune Member

Tina Austin as Commune Member

Jeffrey Bacon as Commune Member

Elizabeth Wingate as Commune Member

Joan Adams as Commune Member

Lisa Maurer as Commune Member

Louise Lasser as Doris (voice) (uncredited)