Carrie Fisher died after suffering a heart attack on Tuesday. She was 60. The actress, who is best known for her role as Princess Leia in Star Wars, was an outspoken advocate for mental health after being diagnosed with bipolar disorder as a teenager. Fisher sat down with PEOPLE to discuss her battle with bipolar disorder — and a scary breakdown on a cruise ship —

while living in the spotlight. Read the 2013 profile below:

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On Feb. 11, two days before Carrie Fisher boarded ship as a headliner for a gay cruise in the Caribbean, she had a nightmare: An armed militia lay in wait on the boat, and in the dream she warned her assistant, “You don’t have to go, but I do!” Despite that premonition, they set sail from Aruba, Fisher’s bulldog Gary in tow. “It was whatever pathetic thing I picked up from my mother [Debbie Reynolds],” says Fisher. “You know, the show must go on.”

Unfortunately, it did. By the time Fisher took the stage, the 56-year-old bestselling author, screenwriter and Star Wars actress was in the throes of a bipolar episode. Shocked audience members watched as she rambled, slurred words and mumbled lyrics. Her dog relieved himself onstage as some people fled.

“I went completely off the rails,” says Fisher, who wrote about her mental illness and prescription drug addiction in her 2008 memoir Wishful Drinking, also a hit one-woman show. When video of the incident hit YouTube about a week later amid speculation Fisher had fallen off the wagon, her rep issued a statement explaining she’d had “a medical incident related to [her] bipolar disorder” and had gone to a hospital to reevaluate her meds. Still recovering at home in Los Angeles, an upbeat and wry Fisher exclusively opened up to People’s Elizabeth Leonard about how the chaos onstage was nothing compared to the bedlam swirling in her head.

Image zoom Nancy R. Schiff/Getty

I don’t really remember what I did. I haven’t watched the videos that people took. I know it got bad. I was in a very severe manic state, which bordered on psychosis. Certainly delusional. I wasn’t clear what was going on. I was just trying to survive. There are different versions of a manic state, and normally they’re not as extreme as this became. I’ve only had this happen one other time, 15 years ago, so I didn’t have a plan of action. That time I was in a [psychiatric] hospital, and I was being talked to by the television, hallucinating. I wasn’t inside the TV this time, thank God. [But] I was in big trouble.

[On the cruise] I wasn’t sleeping. I was writing on everything. I was writing in books; I would have written on walls. I literally would bend over and be writing on the ground and [my assistant] would try to talk to me, and I would be unable to respond. That was what I spent my teenage years doing: handwrite, handwrite, handwrite to the point where I’m running out of ink. I can’t wait to see what I wrote. I don’t know what the hell it says. I do know this—and it was really bizarre—I was trapped in a metaphor. Everything I looked at had a meaning. Everything was a warning or a sign. I was in a part of my brain I’ve only been in one time before.

My illness took hold when I was 14 or 15 years old—my father [Eddie Fisher] had it too. When I was 12, I went over to his house, and he said, “Come see what I got in Hong Kong!” and he’d gotten 180 silk suits. My dad and I used to do drugs together. We were like badly behaved children. I got sober with a group of people in rehab, and we all got out and they all kind of calmed down, and I went in another direction. I went to a doctor [who diagnosed her with bipolar disorder in her 20s] and said, “I felt normal on acid,” and he said that is consistent with what we know of the manic state.

For years Fisher managed her illness with medication and electroconvulsive therapy, but on the ship, things went awry.

Image zoom Steve Granitz/WireImage

I was eating this medication Seroquel, which is an antipsychotic that I take to sleep. I’ve never taken that many in my life. But I caught it [the manic episode] too late. I had no judgment. [My] medication was going wrong, my sleep cycles were off. It was a perfect storm of events. Imagine going into a manic high—which is a very extroverted energy—and you’re an entertainer and you’re on a stage! I wasn’t drunk. Anyone who knows me knows that’s not possible. On the ship, I had gone to AA meetings a couple times, and those guys were very sweet and grounding for me. They actually came onstage and saved me. Only a former drunk would get onstage with me. It wasn’t like they were walking into a great Hollywood situation.

Fisher got off the ship in Fort Lauderdale the next day, flew to L.A. and checked herself into UCLA’s Resnick Neuropsychiatric Hospital for five days, then moved to a residential facility while adjusting to new medication.

I needed to be there in the hospital. I still was seeing things as signs, [and] I said that I was living in a metaphor. My big gag was “metaphors be with you.” That’s the big gag I got out of it. Word play—I can’t not do that!

But it’s not funny. The only lesson for me, or anybody, is that you have to get help. It’s not a neat illness. It doesn’t go away. I’m just lucky this hasn’t happened more. [In the future] I don’t know if there are setbacks or steps forward. I’m not embarrassed. I’m sorry for my friends and my family. I feel bad for my daughter [Billie, 20, with agent Bryan Lourd]. I don’t want this spectacle-making illness to make a spectacle of me and, in so doing, her. I feel bad that these people had come to be entertained and witnessed a car wreck.