Not since a mescaline-fueled Raoul Duke and Dr. Gonzo were haunted by bats and Gary Busey in the desert in Terry Gilliam’s fevered film of “Fear and Loathing in Las Vegas” have I seen as nightmarish a cinematic road trip as the one in the new comedy “Identity Thief.”

But the nightmare of the Johnny Depp-starring Hunter S. Thompson adaptation is gloriously enjoyable in its ugliness, a celluloid contact high that causes smiles and stifled vomit in equal measure. It’s meant to be a nightmare, and it’s enjoyable as such.

“Identity Thief”? Different kind of nightmare road trip altogether. This one is an ugly, depressing, sporadically funny and mostly unenjoyable waste of two fine actors.

What a shame, especially since the loud, brassy romp actually does something quite bold: It gives “Bridesmaids” co-star Melissa McCarthy a starring role.

But most importantly, here is a film in which the female lead gets the laughs, and the male lead, Jason Bateman, is saddled with the boring straight-man role.

Ponder that for a second. Of 2012’s most financially successful comedies, only the surprise hit “Pitch Perfect” could claim a female lead. There were women-centered hit dramas aplenty, from “The Hunger Games” to “Snow White and the Huntsman.”

But comedies? Almost none (Madea doesn’t count). And following the success of “Bridesmaids,” that’s a real waste of talent.

So let’s praise the powers that be for casting McCarthy, and hope that next time, it’s in a movie that’s actually good.

The always welcome Bateman, the star of the dearly departed and soon-to-be resurrected “Arrested Development,” plays Sandy Patterson, a husband, father and some manner of businessman whose identity is stolen by the garish Sandy Patterson (McCarthy).

OK, her real name is not Sandy Patterson, but she assumes the ID, creates the credit cards, and goes on a spree in her Florida hometown that involves dropping a couple grand on drinks at a club and filling her house with guitars and blenders.

Her deeds destroy the life of the real Patterson, and the Denver resident must fend off creditors, and even the police. Ha ha.

His only recourse – because why would anyone actually listen to him? – is to get to Florida, and attempt to bring back the fake Sandy to face the music.

It’s a solid premise, and because of the sheer likability of Bateman and McCarthy, it leads to occasional laughs. And yes, her backstory is sweet.

But then two inexplicable bad guys appear, because we need that subplot. And a bounty hunter is on the scene. And it goes on. And on.

It seemed to me that most of the jokes were at McCarthy’s Sandy, not with her, and that, coupled with the overall dreariness of the situation Bateman’s character finds himself in, led to a wildly depressing experience. The chuckles mostly feel like eye-gouges, rather than belly laughs – mean and obnoxious.

“Identity Thief” also continues director Seth Gordon’s Sherman-like march to hackery. His career began with the gobsmackingly great “Donkey Kong” documentary “The King of Kong,” but took an odd turn with the financially successful but awful “Four Christmases” and “Horrible Bosses.”

Because of the sheer winning force of McCarthy and Bateman, “Identity Thief” gets a slightly higher rating than perhaps it should. But to see the best of this duo, watch any chunk of “Bridesmaids” or any random episode of “Arrested Development.”

identity thief

Two stars

Starring: Jason Bateman, Melissa McCarthy, Amanda Peet

Director: Seth Gordon

Running time: 111 minutes

Rating: R for sexual content and language.

The Lowdown: When a mild-mannered businessman learns his identity has been stolen, he decides to track down the thief.