It's like the Book of Job at times, the path of protagonist Dominick in HBO's "I Know This Much Is True." He's put through trials that could break a person as he tries to do right by his paranoid-schizophrenic twin, Thomas (both roles played by Mark Ruffalo). Dominick is not as virtuous as the biblical figure, though. He can't get away from his demons because some of them are him.
"He's on a journey of forced self-discovery," says Ruffalo. "Most journeys of self-discovery are forced on us. It's usually something that makes us very uncomfortable, so we don't go until we're forced -- whether through suffering, loss of a person we love, hitting some sort of bottom ... we probably learn the most about ourselves there."
Ruffalo's physical transformations are remarkable: He lost 20 pounds to inhabit Dominick, then gained 35 for Thomas. But it's the depth of those portrayals that define the limited series, which is much more concerned with character exploration than plot movement.
"It was really about the responsibility we have to each other and how, as hard as that can be sometimes, that's where we really grow. And there's nowhere that's more apparent and potent than in families," Ruffalo says of the themes that permeate Wally Lamb's 1998 bestseller.
"There's the idea of masculinity. It's not a mistake that Wally uses twins and one is hyper-masculine and uses violence to solve all his problems, and the other one is effeminate and has this kind of sweetness and care for the world," he says. "In a lot of ways (Thomas is) more free because he's not bound by the toxic masculinity we all learn to survive."
After failed attempts to make it as a feature film with others, Lamb asked Ruffalo, through their mutual agent, to star in and executive produce an adaptation. Ruffalo pitched his friend Derek Cianfrance to write and direct.
Cianfrance says, before they ever met, he had tried to get Ruffalo for the lead in his film "Blue Valentine" (for which Ryan Gosling would gain an Oscar nomination) and jokes he was mad at him for taking the studio rom-com "13 Going on 30" instead (Ruffalo protests that he never received Cianfrance's script).
The two would finally meet as directing peers at the 2010 Sundance Film Festival when "Blue Valentine" and Ruffalo's helming debut, "Sympathy for Delicious," were in competition. Cianfrance says, "We had so much in common, similar upbringings; we were both Italian American. And since that first time I met him, he immediately felt like my brother; over the 10 years I've spent with him, I've realized that everyone who meets him feels like that about him."
Yet when Ruffalo asked him to write and direct "I Know This Much Is True" years later, Cianfrance initially demurred because of the technical concerns.
"I didn't want it to feel like we shot one half in the morning and then Mark put on a mustache and we shot the second half. I wanted to embrace a real process and have him become two different people," he says.