WATCH: Janet Jackson's Interview With ABC's Robin Roberts

In an exclusive interview, Janet Jackson told ABC's Robin Roberts that her family was not naive about Michael Jackson's drug problem, saying that she reached out to her brother throughout the years, but was unsuccessful.

When asked if she tried to help her brother with his drug issues over the years, Janet said: "I did. Of course, that's what you do. Those are the things that you do when you love someone. You can't just let them continue on that way. And we did a few times. We weren't very successful."

She added that Michael was aware of the family's concerns.

"How do I say this?" she asked. "(He) understood that it was out of love, because of caring. But when it's something like that, people can tend to be in denial."

She said Michael was in denial about his problem.

"You can't make ‘em drink the water," she said. "I'm a true believer in prayer, a big believer in prayer. But it's something that you can't do for them. Something they have to do for themselves."

She also talks about her break-up from Jermaine Dupri and said they're still good friends.

"I adore him, absolutely adore Jermaine," she said, while acknowledging that they're no longer a couple. "We're still very good friends to this day."

Asked of if she's seen This Is It, the documentary about Michael as he prepared for a series of London concerts, Janet said she may never see it.