Opens: Friday, July 25 (Columbia Pictures)

The Judd Apatow School of Comedy invariably focuses on adult males who act like adolescents yet over the course of a movie manage to grow up -- at least a bit.

"Step Brothers" -- a Judd Apatow production written by its stars, Will Ferrell and John C. Reilly, and director Adam McKay -- pushes that idea perhaps too far: The only thing that can explain middle-aged men acting like 6-year-olds is mental retardation, and there's nothing funny about that. The idea of middle-aged actors playing adolescents isn't much funnier. Put it this way: Such an idea does not make for an inexhaustible source of comedy.

Exhausted is how many audiences members will feel after squirming through such a repetitive, one-joke comedy. Real adolescents might find the whole thing a hoot, but guess what? The filmmakers made an R-rated movie, which gives Columbia Pictures a real challenge to deliver this film to its most appreciative audience. Did the filmmakers really need dozens of utterances of the F-word to sock across their comedy? Will Ferrell's name insures a solid opening weekend, but that might be it.

The marriage of Nancy (Mary Steenburgen) and Robert (Richard Jenkins) forces their two half-witted, lazy bones, emotionally stunted 40-year-old sons, Brennan (Ferrell) and Dale (Reilly), respectively, to live together as stepbrothers. At first they hate each other, but then discover they have so much in common, as indeed they do.

Their childish pranks and tantrums pretty much destroy Robert's well-upholstered suburban home, his treasured sailing boat and the parents' new marriage, which compels the two men to leave home to live on their own and, yes, grow up a little. The parents might or might not reunite -- that's ambiguous -- but Robert does deliver a moronic speech to the boys about the need to cling to their adolescent selves since that represents their true personalities.

With such a lame premise, the search for laughs grows more frantic with each passing hum-drum minute. That search takes the movie into cruder and cruder territory with no real payoff except for those who cling to their adolescence. A subplot involving Brennan's thoroughly obnoxious brother never goes anywhere. The protagonists' love interests, played by Kathryn Hahn and Andrea Savage, get treated with borderline contempt, portrayed as women without reason or morals. Guess this view of women also relates to men who cling to their adolescence.

Production: Columbia Pictures, Relativity Media present an Apatow Co./Mosaic Media Group production.
Cast: Will Ferrell, John C. Reilly, Richard Jenkins, Mary Steenburgen, Adam Scott, Kathryn Hahn, Andrea Savage, Rob Riggle.
Director: Adam McKay.
Screenwriters: Will Ferrell, Adam McKay.
Story: Will Ferrell, Adam McKay, John C. Reilly.
Producers: Jimmy Miller, Judd Apatow.
Executive producers: Will Ferrell, Adam McKay, David Householter.
Director of photography: Oliver Wood.
Production designer: Clayton Hartley.
Music: Jon Brion.
Costume designer: Susan Matheson.
Editor: Brent White.
Rated R, 99 minutes.