Sleepless nights sap joy and increase anxiety, major study reveals

It’s well known that lack of sleep not only makes you tired, but can also have a detrimental physical impact on your body too.

But a new study has revealed that those sleepless nights are having an even bleaker outcome – they sap your joy and increase the risk of anxiety.

In an analysis of more than 50 years of research on sleep deprivation and mood, researchers wanted to find out the psychological impact of what they called our “largely sleep-deprived society”.

Publishing the findings in the journal Psychological Bulletin, they analysed data from 154 studies that spanned five decades.

Across the studies, there were more than 5,000 participants whose sleep was disrupted for one or more nights. Some were kept awake for extended periods, while others were given shorter-than-normal amounts of sleep.

Another set of participants was periodically woken throughout the night.

The studies then measured at least one emotion variable following the disrupted sleep, with participants self-reporting their mood, and responding to emotional stimuli, as well as being measured for symptoms of depression and anxiety.

The researchers found all three types of sleep disruption resulted in fewer positive emotions, including joy, happiness, and contentment. They also increased symptoms of anxiety, such as rapid heart rate and increased levels of worry.

There were some findings for symptoms of depression, but these were smaller and less consistent. Similar results were found for an increase in negative emotions such as sadness, worry, and stress.

“In our largely sleep-deprived society, quantifying the effects of sleep loss on emotion is critical for promoting psychological health,” said study lead author Dr Cara Palmer of Montana State University.

“This study represents the most comprehensive synthesis of experimental sleep and emotion research to date, and provides strong evidence that periods of extended wakefulness, shortened sleep duration, and nighttime awakenings adversely influence human emotional functioning”.

Palmer added that the negative effects happened “even after short periods of sleep loss,” including staying up an hour or two later than normal.

“We also found that sleep loss increased anxiety symptoms and blunted arousal in response to emotional stimuli,” she said.

‘Largely sleep-deprived society’

The researchers noted that a limitation of the study was that the majority of participants were young adults with an average age of 23.

A more diverse age sample in future research could provide a better understanding of sleep deprivation’s effect on emotion.

They would also like to examine sleep loss effects in different cultures, as most of the research in this study was conducted in the United States and Europe.

“Research has found that more than 30 per cent of adults and up to 90 per cent of teens don’t get enough sleep,” Palmer said.

“The implications of this research for individual and public health are considerable in a largely sleep-deprived society. Industries and sectors prone to sleep loss, such as first responders, pilots and truck drivers, should develop and adopt policies that prioritise sleep to mitigate against the risks to daytime function and well-being”.