According to the the 'Robert Downey Jr Film Guide' web-site, "supposedly, the director ['Marek Kanievska'] suggested Robert Downey Jr. and Andrew McCarthy should go out and party to 'get into character' which ended with Downey in the middle of Santa Monica Boulevard, howling at the moon, and McCarthy had to bail him out of jail".
Because the novel didn't have a central plot or a core set of protagonists, but was more a set of interwoven events happening to a larger group of friends, this film differs considerably from the novel. In a surreal twist, the sequel novel, 'Imperial Bedrooms', has the original novel's characters aware of the film version of "Less Than Zero".
In an interview, source novelist Bret Easton Ellis once said of this film adaptation of his book 'Less Than Zero': "Of course, I envisioned everybody in the book as blonde and everybody in the movie is a brunette".
Both the book and film of Less Than Zero (1987) and its reported sequel, titled Imperial Bedrooms, are named from an Elvis Costello song and album respectively. "Less Than Zero" is the first single off of the "My Aim is True" (1977) album whilst "Imperial Bedroom" is the name of Costello's 1982 album.
Jami Gertz is the actress who plays Blair in this movie based on the first novel by Bret Easton Ellis. In another book written by Ellis, "American Psycho", Patrick Bateman inquires about actress Jami Gertz at the Video Visions video store in New York's Upper West Side. The video store clerk does not know who Gertz is. Bateman then fantasizes briefly about having sex with Gertz while trying not to pay attention to someone talking to him.
According to Wikipedia, source novelist [Bret Easton] "Ellis hated the film initially but his view of it later softened. He insists that the film bears no resemblance to his novel and felt that it was miscast with the exceptions of [Robert] Downey [Jnr] and James Spader".
According to the 1987 article "Sanitizing a Novel for the Screen" published in 'The New York Times', Pulitzer Prize-winning playwright Michael Cristofer, who wrote a screenplay for this film that got rejected, said the experience working on this film was an ugly one.
Cinematographer Edward Lachman has said that the completed picture was originally a lot edgier and the 20th Century Fox studio, who felt the property was too edgy anyway and had limited the film's cost budget, wanted to tone down the movie and make it more commercial audience friendly, and did this by taking the film away from director Marek Kanievska in post-production.
Producer Marvin Worth in June 1985 first optioned the film rights to Bret Easton Ellis' then unpublished "Less than Zero" novel by purchasing an option for the small amount of US $7,500 on the proviso that the 20th Century Fox film studio would make the movie.
A test screening of 15 to 24 year olds revealed that the sample disliked Robert Downey Jr.'s character. So reshoots were conducted with additional footage to show his and Jami Gertz's characters in a better light which included the happy and celebratory early graduation sequence.
Some of the film's english translations of this film's foreign film titles, according to the "Robert Downey Jr. Film Guide" website, were as follows: "Argentina: Corrupción en Beverly Hills (Corruption in Beverly Hills); Brazil: Abaixo de Zero (Less than Zero); Denmark: Livet i overhalingsbanen (Life in the Fast Lane); Finland: Alta Nollan (Under Nothing); France: Neige sur Beverly Hills (Snow on Beverly Hills); Germany: Unter Null (Under Zero); Israel: Young in Trap (English translation); Italy: Al Di Là Di Tutti i Limiti (Beyond All the Limits); Poland: Mniej Niz Zero (Less Than Zero); Spain: Golpe al Sueño Americano (A Blow to the American Dream); [and] Sweden: Noll Att Förlora (Nothing to Lose)".
The producers and 20th Century Fox studio executives frequently argued about amount of decadence that would be depicted in this movie with the film being "meetinged to death" as the New York Times reported.
Marek Kanievska was hired as director for two reasons and these were based on his direction of his critically acclaimed 1984 film Another Country (1984). This was because Kanievska had in that film (1) fashioned unsympathetic characters making them sympathetic and (2) been able to handle themes of bi-sexuality and sexual ambivalence.
The last name of Andrew McCarthy's character, Clay Easton, is the same name as the middle name of source novelist Bret Easton Ellis. Clay's surname was not given in Ellis' source "Less than Zero" novel. Its use here in this film is a direct reference to the author.