“This sounds hyperbolic,” says Porochista Khakpour, “but I’ve really felt like I’ve been dying the past few months.” She has, when we speak, temporarily taken up residence in San Francisco, where she’s been undergoing “some pretty intense Lyme therapies” and also recovering from a winter that ravaged her health. “Maybe one or two other times in my life were as challenging as this one,” she says, and then laughs. “So this is how you’re encountering me.” Midway through our conversation, there will be an earthquake.

It’s a weird time for Khakpour to have a book coming out. If life were fiction, it would be poetic, but it isn’t, so it’s not. “Some bro I don’t know online was like, ‘Oh, this is perfect promotion for your book!’ ” she says. “And I was like, ‘Uh, yeah, no.’ This was exactly what I hoped would not happen.”

You could say that Sick is about Lyme disease, and while you wouldn’t be wrong, exactly—certainly, it is more about Lyme disease than most books are about Lyme disease—you’d also be missing the point. It’s a first-person interrogation into the unsettlingly thin membrane between sickness and health. In mostly chronological order, Khakpour leads us through scenes from her life: a surgery for a childhood ear infection in Los Angeles, to which she credits both her suspicion of doctors and her fascination with drugs; her substance-fueled college years and the first mysterious bouts of illness as a 20-something in New York: “I didn’t feel right,” she writes. “That I knew, but I also knew it had been years since I’d understood what that felt like.” There are years in Baltimore, Chicago, rural Pennsylvania, and Santa Fe. Each location is like a suspect in a murder mystery.

“I used to joke about wanting to write Sex, Drugs & Lyme Disease,but that’s not really this book,” Khakpour says. “The point of it for me is this larger discussion about illness and the body.” It is missing many of the pieces of a neat medical narrative. For example: a beginning.

It is possible she got the tick bite on a childhood hike in Los Angeles. Or as a student at Sarah Lawrence College. Or on trips to the Hamptons with a succession of boyfriends in her 20s. Or maybe it goes back further: to infancy, to her early childhood in Iran. Did she ever feel great? “There’s a quick way I can answer that, and be like, Yeah, sure, I used to run, I did yoga, but then I’m like—wait a sec, hang on. I never felt quite OK in my body, actually. What’s that about, you know?”

What’s that about is her central question, one as much about identity as about illness. “I had to create an investigation,” she tells me. “The investigation was not going to be into the history of Lyme disease or anything like that, but something far more personal, to figure out where did this come from, and what has this meant in my life?” And to really look at Lyme meant looking at everything else, too. “So it was like, OK, Porochista, let’s talk about addiction; let’s talk about PTSD; let’s talk about all those troubled aspects of your life that might complicate the narrative.” If she was going to do this, she was going to do it honestly. “It wasn’t just the story of like, ‘One summer I had a tick bite, and then I went to the doctor, and then it was frustrating.’ ”

Khakpour did not set out to write a memoir. She was a novelist and a journalist, and then, after her first novel, Sons and Other Flammable Objects, came out in 2007, she started writing essays about Iranian-America for the New York Times and became an essayist, too. (Later, Khakpour wrote an essay about those essays for Catapult.) Maybe someday in the future she’d gather those essays into a collection, but she definitely wasn’t planning on becoming a memoirist—she definitely wasn’t planning on becoming someone who wrote, at length, about her own chronic illness and addiction. That wasn’t her thing. “I didn’t identify with it,” she says. “Or I wouldn’t let myself identify with it.”

Except that, in a way, she was writing about it. After Sons came out, but before the publication of her second, more surreal novel, The Last Illusion, she’d taken to posting “desperate” updates about her health on Facebook. The posts found an audience of other sick people, some of whom began urging her to write about illness for real. “And I remember this one woman got kind of mad at me about this issue,” Khakpour says. “She basically said it was my duty to write about this. And I kind of felt like, Hmmm, is it my duty? But I also knew what she meant.” Eventually, Khakpour, still riding the ups and downs of her own illness, came around to the idea of writing something, only she envisioned it might be a chapbook—something indie—which she’d hand out “at places with sick people.” It was an editor friend who suggested she might have more impact if she actually published it. “That was the first time I thought, Wait a sec, could this actually exist?”

A different kind of illness memoir might weave together theories on Lyme disease, threads of Lyme history, Sontag’s Illness as Metaphor. Khakpour did not want to write that book. She was exhausted by a strain of memoirs—often by women—that “felt overly dependent on cultural criticism,” as though to ward off against accusations of narcissism. “If I’m going to write this thing that’s going to be my truth, and it’s going to be raw and ugly and very real, why on Earth would I drag in anything else?” she says. Have I read William Styron’s Darkness Visible, she wants to know? (If I haven’t, I should, unless I’m very depressed.) Because Styron didn’t buttress his experience of depression in theories and historical figures. “He just told his story. That’s it.”

And anyway, she didn’t want to write about the history of Lyme disease; being bitten does not necessarily transmit a passion for the minutiae of tick-borne disease. “The point of this book is not that I developed a great interest or fetish for illness. It’s the opposite of that.” In her fantasy, she isn’t a leading expert on Lyme; in her fantasy, she never has to think about Lyme again.

And then there’s the earthquake. It’s minor, 3.5, but still. “Goddamn, that is so scary,” Khakpour says, checking Twitter. “You’re getting great setting for this.” It’s all very thematic. She has long been afraid of earthquakes, even as she felt tremors in her own body—an early symptom of something.

“I’ve been telling people, my book isn’t really going to teach you much about this disease. Maybe it will in some inadvertent way. But it’s going to tell you something about someone who’s lived through some of this stuff, who’s continuing to struggle through some of this stuff,” Khakpour says. “I think it’s very, very, very lonely being a human on this Earth,” she reflects. “And so for me, that’s what memoir’s purpose is, to make us feel less alone.”

Rachel Sugar is a writer living in New York.