Director-producer Reitman and screenwriter Cody previously collaborated on the films "Jennifer's Body" and "Juno."
Their latest film is to begin principal photography in New York this month.
Paramount worked with Reitman as a director on "Up in the Air" and as a producer on the upcoming release "Jeff Who Lives at Home."
Oscar-winning actress Charlize Theron will star alongside Patrick Wilson and Patton Oswalt in "Young Adult."
"We immediately jumped at the chance to work with Jason again," Paramount Film Group President Adam Goodman said in a statement Friday. "He's one of the most talented filmmakers working today and we look forward to this next collaboration."