A new US study reports this week that loneliness is linked to sleep disruption: people who scored themselves high on loneliness were also the ones whose monitored sleep patterns were most fragmented. Reporting their findings in the 1 November issue of the journal Sleep, lead author Dr Lianne Kurina, of the Department of Health Studies at the University of Chicago, and colleagues found however, that loneliness does not appear to be linked to duration of sleep.

In a press release from the American Academy of Sleep Medicine, Kurina said that:

“The relationship between loneliness and restless sleep appears to operate across the range of perceived connectedness.”

She and her co-authors were interested in further exploring reports that loneliness is linked to poor health. One theory is that lonely people don’t sleep as well as those who feel more connected to others.

“We wanted to explore one potential pathway … the theory that sleep – a key behavior to staying healthy – could be compromised by feelings of loneliness,” explained Kurina, adding that:

“What we found was that loneliness does not appear to change the total amount of sleep in individuals, but awakens them more times during the night.”

For their cross-sectional study, Kurina and colleagues recruited 95 adults of of a traditional, close-knit farming community in rural south Dakota. They compared self-reported levels of loneliness assessed through interviews with measurements of their sleep cycles.

The participants were aged 19 and over and their average age was 39.8 years. 55% were female. In the interviews they answered questions about loneliness, depression, anxiety, and stress, as well as subjective sleep quality and daytime sleepiness.

To measure objective sleep properties, the researchers gave the participants wrist actigraphs which they wore for a week.

None of the participants was socially isolated, yet their perceptions of loneliness varied, and the researchers found that higher loneliness scores were linked to significantly higher levels of sleep fragmentation. This was after taking into account potential confounders like age, sex, body mass index, risk of sleep apnea and negative mood (assessed from responses to questions about depression, anxiety and stress).

They also found that loneliness was not linked to total sleep duration, subjective sleep or daytime sleepiness.

The findings are similar to a study published in 2002 by the American Psychological Society that compared students’ perceptions of loneliness with their measured sleep quality. This found that the ones who reported feeling the most lonely had more broken night-time sleep.

Kurina said when you look at the similar results of the two studies, you realize that loneliness and social isolation are not the same thing.

Loneliness is about perceived social isolation, feeling like an outcast, and reflects the difference between what a person wants and what they actually have in their social connections with others.

“Whether you’re a young student at a major university or an older adult living in a rural community, we may all be dependent on feeling secure in our social environment in order to sleep soundly,” said Kurina, adding that the findings of studies like these help us further understand how social and psychological factors impact our health.

While these conclusions seem plausible we should however, remind ourselves that this was a cross-sectional study and thus at the most can only assert whether links are strong or not: it cannot establish the direction of cause and effect.

For example, an equally scientific explanation from these results could be as follows: disrupted sleep affects mood in a way that makes people less likely to engage with others to the level that they would like. This may seem less plausible, but the study is not of a design that can rule this out.

Written by Catharine Paddock PhD