JOSHUA — ** 1/2 — Jacob Kogan, Sam Rockwell, Vera Farmiga; rated R (profanity, drugs, sex, brief nudity, violence, brief gore, slurs)

"Joshua" implies more than it shows. It is, after all, a film about a 9-year-old boy who may have murderous impulses toward his parents and his newborn sister. That is potentially upsetting material, of course, so the restrained approach here is probably the best way to go.

But it's far from perfect. "Joshua" is an at-times-unsettling thriller that unsuccessfully blends horror and dark comedy — as if someone tried to stitch together the "Omen" with "Problem Child."

Newcomer Jacob Kogan plays the title character, Joshua Cairn. Though his was a rough birth, he's been pretty much a perfect child since then. He is well-groomed, well-spoken and polite toward his parents and other adults. He also has musical talent on piano and appears to be well ahead of his fellow students on the learning curve.

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However, there's something disquieting about the way he looks at his baby sister, and the resulting friction has already unhinged his emotionally fragile mother (Vera Farmiga). But Joshua's father (Sam Rockwell) only becomes suspicious of his son when things really get bad in the Cairn household.

Co-screenwriter/director George Ratliff fills the film with odd humor and references, including an homage of sorts to the 1925 Russian classic "Battleship Potemkin."

But the film's bizarre ending seems a bit off.

Fortunately, Ratliff's cast is strong. Rockwell's slow descent into madness is convincing, and Farmiga ("The Departed") is terrific, as always. Kogan is impressive as well, though he plays his part with a deadpan expression most of the time.

"Joshua" is rated R for some strong sexual language (profanity) and other sexually suggestive material and references, drug content and references (tranquilizers and mood-altering drugs), simulated sex, brief female nudity, implied violence, some violent child abuse and a brief violent fall, brief gore and slurs based on ethnicity. Running time: 106 minutes.