Directed by William Brent Bill, who wrote the script with Matthew Peterman, “The Devil Inside” opens with the promising laugh line that “the Vatican did not endorse this film nor aid in its completion.” It’s downhill from there, despite Pixie Le Knot’s Gumby physicality and some solid acting, including from Suzan Crowley as a mental patient, Maria Rossi, who may be possessed. The story turns on her daughter, Isabella (Fernanda Andrade), who travels to Italy with a “documentary” filmmaker, Michael (Ionut Grama) to find out what’s, er, bedeviling mom. Years earlier, mommy scariest killed three religious functionaries who were trying to perform an exorcism on her, a splatterfest seen briefly and which led to her being locked up in an Italian institution. In Rome — the plane tickets were surely the costliest items in this production — Isabella attends a class at some kind of exorcism academy, where bright young things in clerical black discuss how to tell the difference between the mentally ill and the possessed. Two of the brightest are earnest, eager priests, Ben Rawlings (a good Simon Quarterman), and David Keane (Evan Helmuth, also rising above the occasion), who perform renegade exorcisms. They invite Isabella along to one, and she returns the favor, with more perilous results, by introducing them to her mother. Michael the filmmaker tags along, capturing all the shrieking, cursing, howling, body twisting and slamming with phony surveillance images and irritatingly palsied camerawork. The scariest thing about “The Devil Inside” is that a major studio like Paramount Pictures, which is distributing it, may be able to squeeze more profit out of a tedious, tediously exhausted subgenre that was already creatively tapped out when “The Blair Witch Project” spooked audiences more than a decade ago. (This movie was shown to critics only the night before it opened theatrically, probably to bypass reviews like this one.) Clearly, when a cheapie pickup like “Paranormal Activity,” which Paramount released a few years ago, turns into franchise gold, there’s just no stopping the banality. The first “Paranormal” cost about $10,000 to make and raked in more than $100 million domestically, which is why a fourth installment will be released this year. “The Devil Inside” is rated R. (Under 17 requires accompanying parent or adult guardian.) Ye olde exorcism mayhem. THE DEVIL INSIDE Opened on Friday nationwide. Directed by William Brent Bell; written by Mr. Bell and Matthew Peterman; director of photography, Gonzalo Amat; edited by Timothy Mirkovich and Mr. Bell; music by Brett Detar and Ben Romans; production design by Tony Demille; costumes by Terri Prescott; produced by Mr. Peterman and Morris Paulson; released by Paramount Pictures. Running time: 1 hour 25 minutes. WITH: Fernanda Andrade (Isabella Rossi), Simon Quarterman (Ben Rawlings), Evan Helmuth (David Keane), Ionut Grama (Michael), Suzan Crowley (Maria Rossi), Bonnie Morgan (Rosa Sorlini) and Pixie Le Knot (contortionist double).