In a new study, researchers have looked at how loneliness and sleep are connected over many years and across different life stages.
They examined both long-term development and how loneliness and sleep were linked at specific points in time.
Over time, the pattern showed that lonely young people did not have a higher risk of sleeping poorly later in life. Poor sleep in youth, however, was associated with slightly higher levels of loneliness in adulthood.
Adults who felt lonely often experienced poor sleep at the same time. And those who slept poorly were more often lonely. The same pattern was observed among adolescents.
The researchers used data from the Trøndelag Health Study (HUNT), which is one of the largest health studies ever performed. The figures came from three different surveys conducted between 1995 and 2019.
Annonse
There were almost 2,200 participants in total. 60 per cent were women.
Became less lonely over time
The researchers also saw that the participants' loneliness decreased over time. Loneliness was therefore less common among adults than among adolescents.
"We chose a long-term perspective because both loneliness and sleep change over time and can have long-lasting consequences," Nayan Deepak Parlikar writes in an email to Science Norway.
She is the lead author of the new study.
"Loneliness can lead to increased mental strain such as anxiety, depression, and inner turmoil – factors that are closely linked to sleep problems," she writes.
"At the same time, poor sleep can make it harder to function socially, which may intensify feelings of loneliness. In other words, my findings point to a reciprocal and self-reinforcing relationship," she writes.
Until recently, Parlikar was a PhD candidate at NTNU. She is now a postdoctoral researcher at the National Institute of Occupational Health (STAMI).
More common among adolescents
Parlikar explains that it's primarily among young adults that poor sleep appears to have affected loneliness.
Those transitioning from adolescence into adulthood were most at risk. The researchers believe this is due to the major changes that occur during this stage of life.
Those who were entering adulthood were most vulnerable, says researcher Nayan Parlikar.(Photo: Anne Line Bakken / NTNU)
"People often leave established social circles and takes on new roles. Expectations for independence increase. Many lose structured daily meeting places, while demands increase," Parlikar writes.
This stage of life often involves education, new jobs, and changes in living situations.
"For some, this can lead to loneliness, which may in turn affect both mental health and sleep," she explains.
Annonse
Over time, loneliness tends to stabilise. This is often linked to becoming more settled in life, with work, family, and stable relationships.
"Nevertheless, it's important to stress that loneliness is not just a youth phenomenon. A significant proportion of adults also experience long-term loneliness," writes Parlikar.
She adds that this is especially true for those who do not establish stable social relationships during their transition into adulthood.
Self-reported information
There are some weaknesses in the methods used in the study, according to Parlikar.
She points to the long follow-up period and the large sample as strengths of the study.
"At the same time, the study is based on self-reported data," she writes.
She explains that this brings a certain degree of uncertainty.
Loneliness was measured with just one question, meaning the researchers could not explore different dimensions of the participants' experiences.
"We also cannot determine definitive cause-and-effect relationships. Still, the results strongly suggest important developmental patterns," she writes.
More young people are lonely. But it's not a youth phenomenon, says Nayan Parlikar.(Stock photo: Tyler Olson / Shutterstock / NTB)
Can not determine cause and effect
"Sleep and mental health are very closely linked," says Ingvild West Saxvig. She is a senior adviser at the National Centre for Sleep Medicine.
Saxvig explains that the researchers have conducted both cross-sectional and longitudinal analyses. The former explores information collected at a given point in time.
Sleep researcher Ingvild West Saxvig is not surprised by the findings.(Photo: Siw Ellen Jakobsen)
The latter examines information collected at multiple points in time. This type of data can reveal how patterns typically unfold for individuals over time, explains Saxvig.
"Neither of these approaches can definitively establish causal relationships. To do that, randomised controlled trials are required," she says.
Such studies allow researchers to ensure that the groups being compared differ only in the specific factor under investigation, making it easier to identify what actually causes any observed differences.
"Even so, longitudinal studies can indicate what occurred first and what followed later," she says.
Anxiety and worries cause sleep problems
"How might sleep problems and loneliness be connected?"
"One explanation may be that sleep and loneliness affect each other directly or indirectly. It can go both ways. Loneliness may trigger anxiety and worries, which can interfere with sleep. At the same time, poor sleep can can make it harder to participate in social interactions, and thereby lead to loneliness," says Saxvig.
She also notes that other underlying factors may create the impression of a direct link between sleep and loneliness, even if the relationship is more complex.
"For example, anxiety, depression, stress, lifestyle habits, health problems, and a lack of social support may contribute to both loneliness and sleep problems," she says.
Saxvig explains that earlier studies have shown a link between loneliness and poor sleep.
Connected to overall health
A meta-analysis conducted by American researchers in 2020 summarised the findings from 84 studies on the topic.
In the article, the researchers write that the relationship between sleep problems and later loneliness – and vice versa – was significant.
In another meta-analysis, American researchers concluded that there is growing evidence that loneliness is linked to other aspects of health. This review included 27 studies.
However, the long-term relationship between loneliness and sleep remains unclear, according to the researchers.
This is where researcher Nayan Parlikar believes their study adds valuable insight to the field.
"Need for early measures"
"This is yet another study showing how much can be gained by preventing and treating sleep problems. Not only for the individuals concerned, but also in terms of socioeconomic benefits," says Saxvig.
"There is a need for early and broad measures," writes Parlikar.
She believes the stigma surrounding loneliness is a problem:
"Loneliness should be viewed as a societal responsibility, not just an individual problem."
