New study reveals the hidden emotional cost of sleep deprivation

In a world that never sleeps, cutting back on slumber has almost become a badge of honor. But what if the price of those extra waking hours is more than just a caffeine dependency and an occasional yawn? A new study published in the Journal of Sleep Research suggests that sleep deprivation could be robbing us of our ability to fully enjoy life’s happier moments.

By using a series of emotion-inducing film clips, researchers have unveiled a subtle yet significant effect: while our negative emotions seem to weather the storm of sleepless nights, our positive feelings take a hit, becoming less intense. This nuanced understanding of how sleep affects our emotional well-being could have profound implications, particularly for those burning the midnight oil in high-stress jobs or navigating the demanding schedules of college life.

The Drive Behind the Discovery

The motivation for this research sprang from a recognition of sleep deprivation as an unavoidable aspect of modern living. From the relentless demands of emergency services and transportation to the nocturnal schedules of the entertainment industry, the necessity for round-the-clock alertness spans across many sectors. Yet, while the cognitive downsides of sleep deprivation are well-documented, its impact on our emotional landscape remains less understood.

Previous studies have shown mixed results, with some suggesting that sleep deprivation amplifies emotional responses, while others indicate a dampening effect. The researchers aimed to clarify this ambiguity, particularly focusing on whether sleep deprivation affects positive and negative emotions equally and if these effects are observable outside the controlled environment of a lab.

“Sleep deprivation has effects on all kinds of biological and psychological processes. As a clinical psychologist, I have always been most interested in how poor sleep affects emotions because this seems to be most directly relevant to mental health,” said study author Jared Minkel, the chief science officer at PredictView and an adjunct psychology professor at the University of Rhode Island.

Unpacking the Study

Conducted at a large Northeastern university during the 2017–2018 academic year, the study drew participants from the university’s undergraduate student population, leveraging a dual recruitment strategy that involved soliciting volunteers from a larger ongoing survey as well as reaching out through flyers and emails within the university community. The final sample included 33 female and 2 male participants.

At the heart of the experiment were 16 film clips, curated for their validated emotional elicitation properties. These clips were categorized into positive, neutral, and mixed emotions, with scenes ranging from uplifting moments of joy and humor to everyday mundane activities, and even to complex scenarios that might evoke a blend of amusement and concern.

Participants viewed these clips in a sequence designed to prevent clustering of similar emotional stimuli, thereby minimizing the potential for emotional desensitization or bias in responses. This viewing took place in a controlled laboratory setting, designed to minimize distractions and standardize the testing environment across participants.

Emotional reactions to each film clip were recorded immediately after viewing, using a modified version of the Self Assessment Manakin to separately evaluate positive and negative emotions. This was followed by a post-film questionnaire that sought to quantify the intensity of specific emotions elicited by the clips.

Before and after the film clip viewing session, participants completed assessments of their mood and subjective sleepiness. Additionally, they engaged in a 10-minute Psychomotor Vigilance Task (PVT), a reaction time task designed to objectively measure attentional impairments attributable to sleepiness—a common consequence of sleep deprivation.

Findings: The Emotional Cost of Sleep Deprivation

The study’s findings paint a nuanced picture of the emotional toll exacted by sleep deprivation. Higher levels of subjective sleepiness reported by participants were significantly associated with diminished positive emotional responses, particularly to the mixed-emotion film clips. This indicates that sleep deprivation more severely impacts our capacity to experience positive emotions, as opposed to negative ones.

“I would like the general population to be aware that when they don’t protect enough time for sleep, it is likely to rob them of joy and humor,” Minkel told PsyPost. “What this study showed was that this loss is big enough to notice in a group of people who still got some sleep, just not enough to feel well rested. We also found that these positive feelings were lower in response to film clips that had a mix of positive and negative aspects, depending on how you look at them. This is more like what we experience in real life where every situation we experience has a mix of good and bad elements.”

“My main surprise was how incredibly sleepy these participants were in their day to day lives. I have worked in a number of sleep clinics and you expect to see those kinds of sleepiness scores there, but I was honestly pretty concerned to see them in a general students population. There is a growing understanding of the mental health challenges young people face today and I think the fact that so many people feel sleepy on any given day is part of that picture.”

Navigating the Limitations and Future Horizons

Despite its illuminating insights, the study acknowledges certain limitations. The sample size, though adequate for preliminary findings, was relatively small and not diverse enough to generalize the results across different demographics. Additionally, the naturalistic setting of the study, while offering real-world relevance, also introduced variables such as caffeine consumption and physical activity, which could potentially mask or amplify the effects of sleep deprivation on emotions.

“One really important caveat here is that this study was not about insomnia,” Minkel noted. “People with insomnia generally protect enough time for sleep, often too much. This study was about people who feel sleepy and was done in the context of other studies that have experimentally manipulated sleep.”

“We did not do that here; our participants slept as much or as little as they usually do, but I would not want people who are unable to get good sleep to have one more thing to worry about. I really hope that students, shift workers, and busy adults who are over-scheduled read this and consider protecting a little more time for sleep. Something in the 7 to 8 hours per night range.”

Looking ahead, the researchers advocate for a more controlled, larger-scale study to further investigate the asymmetric impact of sleep deprivation on positive versus negative emotions. Such future endeavors should aim for a more diverse participant pool to ensure the findings are universally applicable. Moreover, exploring the neural and physiological underpinnings of these emotional changes could provide deeper insights into how sleep deprivation fundamentally alters our emotional processing.

A Wake-Up Call on Sleep and Emotion

This study stands as a poignant reminder of the often-overlooked emotional toll of sleep deprivation. While the hustle culture may glorify the grind of extended working hours, the subtle erosion of our capacity to feel joy and satisfaction could be a high price to pay. As we continue to unravel the complex tapestry of sleep’s role in our lives, this research highlights the importance of prioritizing sleep not just for cognitive and physical health, but for preserving the vibrancy of our emotional experiences as well.

“I do this kind of research with the hope, and strong conviction, that it leads to better interventions,” Minkel told PsyPost. “There is an incredibly close connection between how well we understand a problem and how effectively we can deal with it. The pandemic showed this on a really accelerated scale. As our understanding of the structure and function the virus improved, we developed more effective behavioral and ultimately pharmacological interventions.”

“Our understanding of the emotional consequences of sleep deprivation is growing much slower of course, but as the scientific community studies it from different perspectives, including neurobiological as well as behavioral, we will see improved treatment. Sleep problems occur in a vast number of medical as well as mental health disorders, so understanding the extent to which sleep is responsible for changes in mood is quite important. It is possible that emotional changes due to poor sleep might be mistaken for depression until the science improves here.”

The researcher added: “thank you to my research mentor, Prof. David Dinges, who is now retired. He gave me incredible support and freedom to pursue this line of work when I was a new graduate student in his lab. Sleep deprivation and emotion was not a hot topic at the time and I am grateful for his guidance in navigating a new area of research.”

The study, “Insufficient sleep blunts positive, but not negative, affective response to emotionally complex film clips“, was authored by Jared Minkel, Emma Pascuzzi, Zoe Mushkat, Emily Gentes, and Sue K. Adams.