Up-and-coming actress Robin Tunney gauges the feasibility of a role by its fear factor.

"If something scares you, it's probably a good thing," Tunney told The New York Times.In the independent film "Niagra, Niagra," she plays Marcy, a woman afflicted with Tourette's syndrome, a serious neurological disorder often characterized by tics, compulsive gestures and blurting out strange phrases.

"I just remember being so frightened about the role," the 25-year-old Tunney said. "I wanted Marcy to be a person and not a character and not to make it look like some sort of vanity piece. I didn't want it to look like I was on a tirade to be taken seriously."