The founder of Throwing Muses, the seminal American art-punk band, and acclaimed solo artist, who was diagnosed schizophrenic, then bipolar more than 20 years ago, adds that she'd always known for a fact that her illness would prove fatal, "that it would claim me some day."
Sipping tea in New York's Rubin Museum of Art, where she'll perform and read from her new memoir, Rat Girl, later that evening, the 43-year-old mother of four sons confesses: "I'd given up; I just assumed I was going to live a short life."
Then everything changed. "Unbelievable!" exclaims Hersh.
So concerned about her was her friend, a Chicago-based acupuncturist, that she insisted on treating the songwriter-guitarist who has just released her new studio album, Crooked, as a book. Each copy comes with a unique digital code, which unlocks an abundance of online content, including ten new tracks.
"The acupuncture is one of the biggest things that's happened in my life. Ever!" announces Hersh, last seen on the Edinburgh Fringe with her autobiographical show, Paradoxical Undressing.
"My understanding of it was that it's very subtle, for ailments like bursitis. I'd no idea they could treat bipolar disorder with it. It was mind-blowing! I've been on strong medication all my life and it's awful. It makes me feel small, even less on this planet than I am with bipolar disorder," she sighs.
The prescription drugs she's taken over the decades have destroyed her liver and her thyroid. "Medication made my thinking robotic, but I can't be anti it because it helps so many people. However, I've struggled since I've had four pregnancies (her home-schooled sons' ages range from seven to 24] and nursed four babies.
"So there were years when I needed an alternative. People would say, 'Try this, try that.' And I'd think, 'You just don't know what you're talking about. This is my whole planet; I'm trapped here and I will not survive it. When I'm gone, you'll know you didn't know what you were talking about.'"
Nonetheless, acupuncture has proved way more powerful than Lithium, the only drug she could handle. "Lithium was effective, but cross a time zone and my kidneys would fail and my hands would shake so I couldn't play guitar."
In an essay accompanying Crooked, the title song on her new album, she tells how needles were stuck in her feet, arms, legs, head and face in treatments as she gigged across America, culminating in New Orleans, where Hersh and her manager husband Billy O'Connell live with their family. They've another home in Providence, Rhode Island, where Georgia-born Hersh, the daughter of unconventional hippie parents, grew up.
"My friend moved my crooked body into my skin and, in that moment, I swear, saved my life," she says.
Now, Hersh has been told the acupuncture will cure her and that eventually she won't need it any more. "I feel like I did when I was a child; I've never before felt so clean or clear thinking."
Does she fear that a cure might affect her creativity?
"No. My songs are literally auditory hallucinations," she replies. "Sure, I've experienced visual hallucinations while manic but the songs are completely independent of my bipolar disorder. They come to me fully formed. I think the reason I hear them is because of a car accident when I was 16; I sustained a double concussion and started hearing music right after that.
"I trust the songs more than I trust my body. I've a weak body compared to my strong songs. I'm not necessarily the conduit they wanted - I wouldn't choose a little 5ft 3in white girl. I'd have chosen a 6ft-tall black guy with muscles and much bigger balls than me," she says, whooping with laughter. "Seriously, though, there's no place for mental illness in humanity. It hurts. I do think, though, that the songs needed all those extremes from my life, from madness to motherhood, to tell their extreme stories."
Hersh's own story has been one of extraordinary extremes. She founded Throwing Muses when she was 14. By the time she was 18, the band had a major record deal, she'd been diagnosed bipolar and was living in squalid squats and her car when she fell pregnant with her eldest son - "the baby and the band kept me alive," she says. It was 1985, a seminal year in her life and the subject of Rat Girl.
"In the UK my book's called Paradoxical Undressing - Americans can't handle too many syllables," she giggles, explaining that the title refers to the phenomenon experienced by hypothermia victims who feel hot and start to remove their clothing, thus hastening their death.
Nothing in Hersh's life has been more paradoxical than the music business, however.
"You can't stick a dollar sign on sound," she rages. In 2005 with the rock group 50FootWave, she made their Free Music EP available online - before Radiohead got the credit for the innovation. She then launched CASH (Coalition of Artists and Stake Holders), putting a new song online monthly, via throwingmusic.com Fans can download free, or make a financial contribution.
So Crooked is the logical next step. "I couldn't bear the thought of releasing just another disposable, dead plastic CD. I don't care about the squalid music business. I don't need it. I need my children, I need nature and I need a small life. Trying to make your life bigger is insane."
• Crooked, is published by the Friday Project, priced 12.99. Paradoxical Undressing, will be published by Atlantic in January. On 23 July, Hersh appears at The Sage, Gateshead.