Julianne Nicholson has been in and out of character a lot lately. The Medford native played Dr. DePaul on the Showtime drama “Masters of Sex,” costarred with Julia Roberts and Meryl Streep in “August: Osage County,” and will soon star in the Sundance Channel series “The Red Road,” playing a wife and mother with schizophrenia and connections to two very different men. “I read a lot about schizophrenia, and I was surprised by how many people actually on our production had people with schizophrenia in their families. . . . People shared a lot of personal stories with me,” Nicholson told reporters recently at the Television Critics Association press tour in Pasadena, Calif. “And I was very relieved to know that it looks different on everyone, which made me feel a little more relaxed and gave me a freedom to just use these beautiful words and my imagination and what I read and heard and create her version of that. . . . It’s the hardest role I’ve ever played, also, the most exciting.” “The Red Road” premieres on Sundance Channel on Feb. 27.