One of the classic signs of deep depression is the strong, intractable belief that, if you die, your loved ones will be much better off. Even if you can’t bring yourself to commit suicide because of family responsibilities, despair drives you to “pour the misery out of my body in howling electric waves” while hiding in a closet so your children can’t hear your screams.

Which is where Heather Armstrong found herself in 2017, when in the grip of a treatment-resistant depression, her psychiatrist suggested she join a study conducted by one of his colleagues. The experiment mimicked the effects of electroconvulsive therapy through the use of “the Michael Jackson drug,” the powerful anesthetic propofol, by flatlining a patient’s brain in ten sessions spread over several weeks.

Heather takes her readers through the nightmarish pits of despair, vividly illustrating why she was willing to risk her life to to undergo burst suppression — quieting the brain — for fifteen minutes. When her alarm went off every morning, the anxiety it sparked felt like flames covering her body. Showers were a shock, forcing her not only to go from wet to dry and warm to cold, but requiring energy she simply didn’t have.

Preparation for each treatment was painful — after 18 hours of fasting and no liquids, the staff struggled to force 22-gauge infusion needles into her dehydrated veins, a process Heather likened to electrocution — and traumatic for her parents, who watched in terror as the medical team rushed to intubate her after she succumbed to the propofol, since she could no longer breathe on her own. She experienced nightmarish backlash from supplemental medication used to counter the anesthetic’s side effects. But not quite halfway through the regimen, she realized she’d started doing things — showering, putting on pants without an elastic waist, applying mascara — that once seemed impossible, and on a Sunday afternoon, she experienced an breakthrough that indicated the treatment was working as promised.

Heather’s recollection of her journey is gripping, terrifying, and all too realistic for anyone who’s ever suffered severe, unrelenting depression. But there are also moments of levity, such as when waking after a session, she screamed “My mother married Satan, and when he’s here next time you’ll see exactly why she divorced him!” That particular demon, her father, remained unsympathetic to the reality of depression even as he watched his children fight it. But the love of her stepfather, Rob, who did the heavy lifting alongside her mother during the treatment, came into sharper view for Heather: “Now I also know the love of a father who loves me despite the endless differences between us, who dedicated himself to me, showed up and was present and understood and believed and held gently in his palm the silent, ticking moments as my lifeless body rested on that gurney … to drive me there and back home, each time, over and over.

Anyone who’s walked the pitch-black corridors of depression knows how hopeless and lonely the journey feels. But for Heather, the staff of the ECT clinic at the University of Utah, all of whom volunteered their time for the study, reached out to guide her into the sunlight of healing. As Dr. Brian Mickey, the lead physician of the study, told her during check-in one day, “You have so much to live for, and you deserve to feel that way.”