Who's Driving Doug, an emotional coming-of-age story about a college student with muscular dystrophy, is one of those movies that stacks the decks against critical viewers. If you don't like it, you come off as a heartless misanthrope - especially since its titular star, RJ Mitte, actually suffers from mild cerebral palsy.

Happily, Mitte, best known for his terrific turn as Walter "Flynn" White Jr. on Breaking Bad, delivers a strong, understated performance in the low-budget indie drama.

Sadly, the same can't be said of his costars, Daphne Zuniga, Paloma Kwiatkowski, and Ray William Johnson.

Cinematographer David Michael Conley's directorial debut features Mitte as a would-be playwright from Southern California who has struggled with a rare form of nondegenerative muscular dystrophy his entire life. The film is set during several days when his newly hired driver and helper, a chain-smoking, too-cool-for-school dropout named Scott (Johnson), persuades him to go on a road trip to Las Vegas. There, Doug learns to let his hair down and practice a little carpe diem, with help from a kindly escort named Elation (Shanti Lowry).

Johnson, a comic, writer, and director who became a YouTube sensation for his Web series Equals Three, seems determined to play his character as a cross between James Dean and Tom Cruise's character in Rain Man, the 1988 film about a hotshot dude who takes his autistic brother on a road trip that includes a stop in Las Vegas.

When he's not buried in books, Doug pines for a schoolmate, Stephanie. Portrayed by Bates Motel's Kwiatkowski in a dull performance, Stephanie spends all her time calling her professor boyfriend, a fifty-something womanizer who seems entirely uninterested in her.

Why does Doug like this uncharismatic neurotic? He seems far better adjusted than most people around him.

That includes his mother, Alison (Zuniga), an overbearing, narcissistic hausfrau whose rage at the recent death of her husband has made her an intolerable housemate. She alternates between babying Doug and lashing out at him.

Zuniga (Melrose Place, One Tree Hill) overplays the character something fierce.

"You . . . bastard," she intones with psychotic intensity at the camera, a stand-in for her husband's ashes, "you said you wouldn't leave me." OK, then.

It's hard to enjoy a film peopled by so many unlikable people.

Mitte deserves better material.