“I wouldn’t mind—I mean this is the sheer irony of the thing—but I’m the only person I know who doesn’t think it would be delicious to go in to ‘someplace’ for ‘a rest.’ You’d want to hear my sister Claire going on about it…,” writes Marian Keyes, via her fictional private detective Helen Walsh in her new novel The Mystery of Mercy Close.

And Claire and her friend Judy do go on about it–white orchids, the smell of jasmine, Magnum Gold ice cream, new cotton pajamas every single day, fresh out of the packet, and as much Xanax as they want.

“‘But you’d be in a psychiatric hospital,’” Helen points out.

“‘I’m not talking about a psychiatric hospital,’” Claire says. “‘Just a place you’d go for…a rest.’”

“‘The place you go for a ‘rest’ is a psychiatric hospital.’”

Claire thinks for a moment and then exclaims to Helen, “‘You’re such a cow. Can’t you ever let anyone have anything nice?’”

Oh, the deliciousness and irony of Marian Keyes’ writing. Too few Americans are familiar with the Irish author’s work, despite the fact that Keyes has written more than a dozen contemporary women’s novels, two of which are set in the United States, plus two autobiographical books, which, all together, have sold more than 33 million copies worldwide.

The Mystery of Mercy Close is Keyes’ fifth novel about the Walsh family. And though Helen Walsh has always been a running character in her family’s novels, she’s never gotten a book of her own. That’s because Keyes has never been able to relate to Helen. Keyes is a self-described softie; Helen is acerbic and fearless, though they both have wicked senses of humor and a love of Diet Coke.

Then, three and a half years ago, Keyes suffered a major depressive episode. It was so horrific that she prefers to call it a “nervous breakdown.” During the breakdown, Keyes discovered she and Helen have something in common besides Diet Coke and senses of humor. Depression. Like the fictional Helen, Keyes endured visions of circling vultures and a suicide plan involving a Stanley knife.

Helen’s depression, however, isn’t just emotional. It’s financial, too, thanks to the Irish economy. She’s forced out of her foreclosed flat and moves in with her parents…when she’s not sleeping on the living room floor of the former pop star she’s been hired to find–Wayne Diffney, a boy band member who goes missing just days before his old band, Laddz, is about to perform a few reunion concerts.

The Diffney gig is one Helen accepts only reluctantly, despite her desperate financial status, because the man who hired her, Jay Parker, i.e., the Laddz’s manager, is also her ex-boyfriend. And she’s involved with a hunky new boyfriend, Artie, a perhaps too amicably divorced cop.

By the way, Keyes writes great sex scenes.

But those scenes, in fact every word of the book, were painfully slow and difficult to write because Keyes’ depression was so dark and deep that, in essence, she was catatonic. She certainly couldn’t construct sentences or even remember words. What energy she did have, she used to keep from killing herself.

In “an act of desperation,” Keyes says, she was hospitalized, believing, hoping, something magical would happen. “And actually nothing did,” she acknowledges. Over time, though, and in mere bouts, she began to write. “I’d have a good spell where I’d make some progress, and then I’d be back into the molasses head where everything happened really slowly and very frighteningly.”

Yet she’d read over her words, see that her sentences were coherent, and know that maybe she couldn’t write that day, but some day, she could and would write again. That gave her hope, and writing about her own depression through Helen gave her relief.

“Even though she suffers from depression, she’s still Helen. She’s still acerbic,” Keyes says. And placing Helen in a mystery novel–Keyes’s first foray into the genre–enabled her to “retain the integrity of Helen as a kind of pretty tough person.”

As Keyes says, “At the end of the day, I’m a storyteller, I would like to think. And I would like to take people on a journey that takes them away from their own lives, to provide a bit of distraction, a bit of diversion. And I suppose I would hope that people would laugh at some stage during it.”

They will, depression and all.

Suzy Spencer is the author of the memoir Secret Sex Lives: A Year on the Fringes of American Sexuality, in which she talks about her own battles with depression.