Sensing an unfulfilled need in the cinema marketplace, Judd Apatow, king of the slob comedy, offers the first female variant of the genre in “Bridesmaids.” For anybody who appreciates wit and charm it’s a depressing development, but it will probably earn a ton and spawn lots of imitators.

Kristen Wiig, who co-wrote the picture with Annie Mumolo, stars as Annie, a baker whose cake shop has closed down and whose affair with an arrogant womanizer (Jon Hamm) is just the most obvious facet of her dreary personal life. Her mood plummets further when her best friend Lillian (Maya Rudolph) gets engaged and asks her to be her maid of honor.

Annie’s a strange character. We’re supposed to find her endearingly quirky, but though the chirpy Wiig tries desperately to make her likable, she remains disturbingly selfish and irritating. That comes out clearly when Helen (Rose Byrne), the prim, ultra-efficient wife of the bridegroom’s employer, tries not only to usurp the wedding planning, but Annie’s friendship with Lillian too. That sets off a cycle of oneupswomanship between the two, which leads to Annie’s making an utter fool of herself over and over again, in a series of episodes that play like sketches from Wiig’s show, “Saturday Night Live.” One involves her going bonkers on a flight to Vegas for a bachelorette party, another her demolishing a big-budget shower, and a third a bridesmaids’ lunch that leads to gruesome bouts of diarrhea (lots of vomiting and flatulence, ha-ha). There’s also an excruciating sequence of the two women trying to outdo one another in a cascade of toasts at a wedding announcement gathering.

Of course, much of the supposed hilarity has to do with the other bridesmaids, most notably the chunky, lovably gruff gal (Melissa McCarthy) who’s a distaff version of the character Seth Rogen would play in a men’s slob comedy. She has a few funny moments, but the script goes to her too often to pump up the unconscionably overlong scenario (the picture runs a full two hours).

Amid all the pre-wedding highjinks, Annie manages to catch the eye of a remarkably good-natured Irish cop (Chris O’Dowd) along the way, and he proves inexplicably attracted to her. Of course her personal problems get in the way of their potential relationship, but rest assured she’ll eventually see the light. O’Dowd, relaxed and amiable, is easily the most pleasant figure in the film—a welcome oasis of tranquility amidst the hullabaloo, and an especially nice contrast to the hyperactive Annie. But since all their encounters are constructed to be cute, in the worst sense of the word, even this part of the picture isn’t terribly engaging.

The cast go for broke in their effort to breathe life into the weak material, and for the most part come off badly. Wiig is trying to be a wild-eyed Lucy Ricardo type, and grows increasingly annoying as the plot proceeds; but then she has nothing to blame but her own script. Byrne is appropriately uptight and rigid, and manages to suggest the vein of vulnerability in Helen that’s ultimately supposed to make her less than obnoxious, but again the screenplay doesn’t offer her much to latch onto. Under Paul Feig’s typically unsubtle direction McCarthy comes on big and brassy, and would have benefited from some greater distancing to make her less overbearingly; by contrast Rudolph makes virtually no impression. Worst used of all are Hamm, who adopts a smarmy smugness that reduces him to a Hank Azaria type, and the late Jill Clayburgh as Annie’s oddball mother. Like Apatow’s other output, “Bridesmaids” is nicely mounted, with Robert D. Yeoman providing crisp cinematography and editors William Kerr and Michael L. Sale doing their best to smooth over the episodic feel and keep up the energy level. It’s hardly their fault they don’t entirely succeed.

Weddings are trying experiences as a rule, and so is “Bridesmaids.” The attempt to apply the male slob template to female characters is dispiriting, and it’s more depressing to think it will probably be a great success.