Poor sleep can be a cause of anxiety and even unhappiness, study finds

Not getting enough sleep or sleeping poorly can greatly affect people's mood and mental health, according to a new US study looking at 50 years of research.

“We found that all forms of sleep loss – total sleep deprivation, partial sleep loss and sleep fragmentation – resulted in emotional changes. The strongest and most consistent effect was that sleep loss reduced positive mood,” said co-author Cara Palmer, assistant professor and director of the Sleep and Development Laboratory at Montana State University in Bozeman.

“We also found that sleep loss increased feelings of anxiety,” Palmer said. “When experiencing emotional events, people were also more likely to report different reactions than people who were well rested.

“Specifically, they reported feeling less emotional arousal, which is when we feel the intensity of certain emotions in our body, suggesting that in general people felt quieter emotional responses after sleep loss.”

Adults over the age of 18 need at least seven hours of solid sleep at night to be healthy, according to the U.S. Centers for Disease Control and Prevention. When they fall short of that minimum, the price can be high: Studies link poor sleep to an increased risk of obesity, heart disease and dementia, as well as mood disorders.

Despite the risks, more than 30% of adults have a daily sleep debt – when you sleep less than your body needs – of more than one hour, while almost 1 in 10 adults loses two or more hours of sleep every nights, points out a 2022 study.

“Around the world, people rarely get the recommended amount of sleep of at least five nights a week,” Jo Bower, study co-leader and professor at the University of East Anglia in Norwich, England, said in an email. “Our work shows the potential consequences of this for our emotional health, at a time when mental health problems are rising rapidly.”

Types of sleep loss

Published Thursday in the journal Psychological Bulletin of the American Psychological Association, the research analyzed data from 154 studies on more than 5,000 people over five decades.

In these studies, researchers disturbed participants' sleep for one or more nights, either by keeping them awake (sleep deprivation), waking them periodically (sleep fragmentation), or making them wake up earlier than usual (partial sleep loss). of sleep). Participants were later tested for anxiety, depression, mood and their response to emotional triggers.

“Generally, total sleep deprivation had a greater impact on mood and emotions compared to partial sleep loss or fragmented sleep,” Palmer said. “Interestingly, though, the effect of sleep on positive mood occurred even after short periods of sleep loss, such as staying up an hour or two later than usual or after losing just a few hours of sleep.”

The “large and comprehensive” meta-analysis emphasizes the strong connections between mental health and sleep, said sleep expert and pulmonologist Dr. Raj Dasgupta, associate professor of clinical medicine at the University of Southern California Keck School of Medicine. He was not involved in the research.
“Maybe there is truth behind the saying, 'I woke up on the wrong side of the bed,'” Dasgupta said in an email.

“The studies included in the meta-analysis found that individuals who had poor quality and quantity of sleep reported feeling more stressed, irritable, sad, and mentally exhausted. When the subjects resumed normal sleep, they reported a dramatic improvement in mood.”

What is happening?

What is it about sleep that makes our body behave this way? The answers are in the brain, Palmer said.

“We know from previous research that sleep loss affects the neural circuits involved in experiencing rewards or positive experiences, which likely plays a role,” she said. “We also see heightened reactions in areas of the brain that are involved in emotional experiences.

“At the same time, the connections between our brain’s emotional centers and our prefrontal cortex, which helps us properly control our emotional reactions, are impaired.”

Although all types of sleep disorders affected mood, the study found that reactions to emotional experiences were more negative after the loss of REM (rapid eye movement) sleep compared to the loss of slow-wave or “deep” sleep. .

During slow-wave sleep, the body removes potentially harmful materials from the brain – including beta-amyloid protein, a hallmark of Alzheimer's disease – while REM is the phase of sleep in which we dream and information and experiences are consolidated and stored in memory.

“Both are likely to be important, but in different ways,” Bower said. “For example, previous work has shown that REM sleep may be linked to the processing of emotional memories and therefore may have an effect on mood through cognitive processes.”

Slow-wave sleep, however, may be linked to the brain's reward centers, which could influence responses to positive emotional situations, she said.

Deep sleep is considered one of the best markers of sleep quality because typically a person must have relatively uninterrupted sleep to achieve it. Because each sleep cycle lasts approximately 90 minutes, most adults need seven to eight hours of relatively uninterrupted sleep to get restful sleep, according to the CDC.

Impact on anxiety and depression

Sleep loss also worsened symptoms of anxiety and depression, the study found, even in people with no known psychiatric or physical health problems.

“Longer periods of wakefulness resulted in more extreme depressive or anxiety symptoms,” Palmer said. “It is likely that sleep loss may affect people who are already depressed or who are at genetic risk for depression differently. For example, some of our previous work suggests that individuals who are already anxious may experience exaggerated responses to sleep loss.”

Difficulty sleeping can also be one of the first signs of an emerging mental disorder, Dasgupta said.

“Chronic insomnia can increase an individual’s risk of developing a mood disorder, such as depression or anxiety,” he said. “Lack of sleep can be an even greater risk factor for anxiety. The studies included in the meta-analysis show that individuals with insomnia were more likely to develop an anxiety disorder and that insomnia is also a reliable predictor of depression.”

Obstructive sleep apnea, in which the body may stop breathing for 10 seconds or more at a time, can also create fragmented, disturbed sleep, Dasgupta said. This type of sleep disorder “occurs more frequently in people with psychiatric problems and needs to be treated,” he said.

More research is needed to determine the impact of lack of sleep on people with existing mental health disorders, teens and children, but each person should be careful to prioritize sleep in their lives, Bower said.

“Allowing yourself to sleep is an important act of self-care, just like eating well and exercising, Bower said. “It is also important that we make systemic changes that support individuals’ ability to get good quality sleep.

“This includes considering policies related to school start times, work schedules, shift patterns, and access to healthcare that support the treatment of sleep problems.”

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