Robert Downey Jr. says his battle with addiction was probably inherited -- and that his 20-year-old son, Indio, with ex-wife Deborah Falconer, is afflicted with the "family problem," too.

In the October issue of Vanity Fair, Downey opens up about his son, who was last month charged with felony cocaine possession.

"He's his mother's son and my son, and he's come up the chasm much quicker than we did," Downey says. "But that's typical in the Information Age; things get accelerated. ... Pick a dysfunction and it's a family problem."

Downey, 49, also delves into his time in rehab and prison more than a decade ago, saying: "Job one is get out of that cave."

"A lot of people do get out but don't change," he says. "So the thing is to get out and recognize the significance of that aggressive denial of your fate, come through the crucible forged into a stronger metal. Or whatever."

"But I don't even know if that was my experience. It's funny: five years ago, I would've made it sound like I'm conscious of my own participation in seizing the similarities," he adds. "But so many things have become less certain. I swear to God. I am not my story."

These days, the "Iron Man" star is expecting his second child with wife Susan Levin, and says that, on the subject of beating a person's demons, "for some folks it's just a function of age."

"It's perfectly normal for people to be obsessive about something for a period of time, then leave it alone," he says.