"The behavior was tiny little acts of trying to destroy myself,” the actress tells Robin Roberts in a new interview for ‘20/20’

In a sit-down interview with Robin Roberts for a 20/20 special airing Thursday, Washington revealed how she contemplated suicide at the height of her disorder and was “trying to destroy myself.”

The actress, 46, also read an excerpt from her new memoir Thicker Than Water — out Sept 26. — and shared that by the time she went to college her relationship with food and her body had “become a toxic cycle of self abuse that utilized the tools of starvation, binge eating, body obsession and compulsive exercise."

“I could feel how the abuse was a way to really hurt myself, as if I didn’t want to be here,” she told Roberts in the sit-down, a preview of which aired on Good Morning America Thursday. “It scared me that I could not want to be here because I was in so much pain.”

Asked if she considered suicide, Washington responded, “Yeah. Yeah … The behavior was tiny little acts of trying to destroy myself.”

The Scandal star also admitted that she prayed for help with her eating disorder as the condition spiraled out of control and she struggled to maintain her “perfect” image to the outside world.

“The first thing that put me on my knees — like the first time I got on my knees and prayed to some power greater than myself to say like, ‘I can’t do this, I need some help’ — was with my eating disorder,” she said.

“I was good at performing ‘perfect.’ I was good at control. I could party all night and drink and smoke and have sex and still show up and have good grades,” the Little Fires Everywhere star continued. “I knew how to manage; I was so high-functioning and the food took me out. The body-dysmorphia, the body-hatred, it was beyond my control and really led me to feeling like, ‘I need help for somebody, or something, bigger than me because I’m in trouble and I don’t know how to live with this.’ ”

Washington went on to share that while she is in a much better place now with her eating disorder, she still has to “check myself.”

“I wouldn’t say that I never act out with food, it’s just very different now,” she said. “It’s not to the extreme. There’s no suicidal ideation, that is not where I am anymore. But I know, ‘Oh, I’m really in this chocolate, this is good information for me.’ The bottom has gotten a lot higher where just a little discomfort with it is enough for me to know this is a way to check myself. But it definitely looks a lot healthier. It’s a lot easier. It’s a lot saner than it used to be.”

And while the star is usually fiercely private about her personal life, she says sharing her story now is “with purpose.” “I’ve never wanted to share my private life for the sake of fame or for the sake of attention,” she noted.