Selma Blair's Stunning New Memoir Reveals Decades of Alcoholism—and First Getting Drunk at Age 7

Selma Blair is not afraid to go there when it comes to sharing the ups and downs of her personal life — particularly in the wake of her 2018 Multiple Sclerosis diagnosis — but never before has she shared such shocking details from her past.

In her new memoir Mean Baby, and in an interview with PEOPLE, the Cruel Intentions star details her decades-long alcohol addiction, which began at age 7, as well as other horrifying personal trauma (suicide attempts, sexual assaults).

"I don't know if I would've survived childhood without alcoholism," Blair, 49, tells PEOPLE in the latest issue. "That's why it's such a problem for a lot of people. It really is a huge comfort, a huge relief in the beginning. Maybe even the first few years for me because I did start really young with that as a comfort, as my coping mechanism."

For more on Selma Blair's new memoir Mean Baby, listen below to our daily podcast PEOPLE Every Day.

In an exclusive excerpt from Mean Baby, Blair details the beginnings of her alcoholism and how she survived it.

"The first time I got drunk it was a revelation. I always liked Passover. As I took small sips of the Manischewitz I was allowed throughout the seder a light flooded through me, filling me up with the warmth of God. But the year I was seven, when we basically had Manischewitz on tap and no one was paying attention to my consumption level, I put it together: the feeling was not God but fermentation. I thought 'Well this is a huge disappointment, but since it turns out I can get the warmth of the Lord from a bottle, thank God there's one right here.' I got drunk that night. Very drunk. Eventually, I was put in my sister Katie's bed with her. In the morning, I didn't remember how I'd gotten there."

Watch the full episode of People Cover Story: Selma Blair on PeopleTV.com or on the PeopleTV app.

The actress writes that in her early years of drinking, she did not get drunk, "just quick sips whenever my anxiety would alight. I usually barely even got tipsy. I became an expert alcoholic, adept at hiding my secret."

Blair's alcohol abuse escalated in her teens and 20s. She writes about an especially traumatizing incident during a college spring break trip when she was raped after a day of binge-drinking.

For much more on Selma Blair and Mean Baby, pick up the latest issue of PEOPLE on newsstands Friday

"I don't know if both of them raped me. One of them definitely did," she writes. "I made myself small and quiet and waited for it to be over. I wish I could say what happened to me that night was an anomaly, but it wasn't. I have been raped, multiple times, because I was too drunk to say the words 'Please. Stop.' Only that one time was violent. I came out of each event quiet and ashamed."

The actress says that aside from telling a therapist, she'd never spoken about the multiple rapes, but that it was a key part of her story to tell in Mean Baby. And part of her continued healing.

"Writing that stopped me dead in my tracks," she says. "My sense of trauma was bigger than I knew. I did not realize that assault was so central in my life. I had so much shame and blame. I'm grateful I felt safe enough to put it on the page. And then can work on it with a therapist and with other writing, and really relieve that burden of shame on myself."

Sober since 2016, Blair hopes that sharing her journey and the more shocking events from her past will help those living with similar burdens.

"It's a lot, she says. "I wrote the book for my son . . . and for people trying to find the deepest hole to crawl into until the pain passes."

She's also hopeful about what her future holds.

"I'm in a good place," Blair says. "I cannot believe all this happened in my life, and I'm still here and I'm okay."

Mean Baby is available May 17.