Insomnia Common but Often Short-Lived

Megan Brooks

June 07, 2018

BALTIMORE — Each year, about one quarter of Americans experience acute insomnia, but most recover without developing persistent poor sleep or chronic insomnia, a new study suggests.

"Whether caused by stress, illness, medications, or other factors, poor sleep is very common," senior author Michael Perlis, PhD, director of the Behavioral Sleep Medicine program at the University of Pennsylvania Perelman School of Medicine in Philadelphia, noted in a university statement.

"These findings reveal new insights about the paths that acute insomnia takes and can inform interventions that target poor sleep and help people recover sustained sufficient sleep," Perlis said.

He presented the study here at SLEEP 2018: 32nd Annual Meeting of the Associated Professional Sleep Societies.

Transition Data Scarce

Although there is a wealth of data on insomnia prevalence, less is known about how many people transition from acute insomnia to persistent poor sleep, chronic insomnia, or back to good sleep.

Acute insomnia is typically characterized by difficulty falling asleep or staying asleep for as little as 3 nights per week for at least 2 consecutive weeks up to 3 months. Insomnia becomes chronic when it occurs at least 3 nights a week for more than 3 months.

The investigators tracked 1435 adults for 1 year. All were good sleepers over the first 3 months of the study, and all kept a daily sleep diary throughout the year-long study.

During the study, 25% of participants experienced acute insomnia. Of these, about 75% recovered good sleep within 12 months, 21% remained poor sleepers with recurring bouts of acute insomnia, and about 6% developed chronic insomnia.

The finding that most people with acute insomnia return to good sleep is "more than reassuring, it's fascinating," Perlis noted in an interview with Medscape Medical News.

Acute insomnia is the gift of more time when you need it. Dr Michael Perlis

In his view, acute insomnia is "not a bad thing. It's adaptive, it's pre-programmed, and we are supposed to have it. Acute insomnia is probably part of the fight-flight response and, over the course of evolution, it probably was a useful thing to be able to delay sleep to flee or fight. And it can be exploited in modern life as well," said Perlis. "Acute insomnia is the gift of more time when you need it." 

Just Roll With It

Perlis said he's also not surprised that so many people experience bouts of acute insomnia.

"We are wired for it," he said. "But most people recover from it because they roll with it — meaning they don't go to bed early the next night, they don't stay in bed much later the next day, and they don't nap. When you have a bout of insomnia, the right thing to do is nothing. If you had a bad night last night, you've got money in the bank for tomorrow if you don't spend it. And with each passing night of insomnia, and as sleep pressure increases, you have better and better odds of the ship righting itself."

The investigators are now looking into what factors predict recovery from acute insomnia or persistent poor sleep or predict the new onset of chronic insomnia.

Asked to comment, James Rowley, MD, American Academy of Sleep Medicine board member, noted that acute insomnia is often caused by some life trigger, usually, in his experience, the death of a loved one.

"Most people have the coping mechanisms to get over it so that sleep isn't compromised chronically. There is some thought that chronic insomniacs have a predisposition to insomnia. A lot of them are just not the greatest sleepers," said Rowley, who is also from Wayne State University, Detroit, Michigan.

Picking up on that point, David Rapoport, MD, director of the Sleep Medicine Research Program at Mount Sinai in New York City, told Medscape Medical News the original work on insomnia cited an initiating factor and a perpetuating factor superimposed on a person's predisposition to insomnia.

"If you are born with a tendency towards insomnia and you get stressed, you are much more likely to develop it," he explained. "But more importantly what you do in response to it — become anxious, look at the clock when you're not sleeping when you have a big presentation the next day — sends you into a perpetuation phase, which then converts acute insomnia, which is transient, into chronic insomnia. We haven't had, to my knowledge, a very good handle on what that percentage was, so that's where this study is providing new information," said Rapoport.

Acute insomnia, he added, is "totally predictable when you have any kind of stress and all of us live in a very stressful world. Insomnia seems to me to be an almost normal reaction to having a child, losing a parent, job stress, or watching the news. The finding in this study that acute insomnia goes away in 75% is new and interesting. However, the finding that 25% of people with acute insomnia don't recover normal sleep still represents a lot of people," said Rapoport.

The study was supported by grants from the National Institutes of Health and the Economic and Social Research Council. Perlis, Rowley, and Rapoport have disclosed no relevant financial relationships.

SLEEP 2018: 32nd Annual Meeting of the Associated Professional Sleep Societies. Abstract 0359. Presented June 5, 2018.

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