Summary: A large study of British young adults finds a clear link between loneliness and poorer sleep quality — lonelier participants were more likely to feel tired and have trouble concentrating during the day.
Source: King’s College London
New research from King’s College London connects loneliness with reduced sleep quality among young adults.
Researchers analyzed data from more than 2,000 British young adults and found that people who reported greater loneliness were about 24% more likely to experience daytime tiredness and concentration difficulties. The findings were published in Psychological Medicine and highlight how social and emotional factors can influence sleep and daily functioning.
Loneliness, as defined by the research team, is the distressing feeling that arises when a person perceives their social relationships as inadequate. This differs from social isolation: someone can be surrounded by people and still feel lonely, or be socially isolated without feeling lonely.
Although loneliness has been widely studied in older adults, it is also common among younger people. National surveys have shown that loneliness is particularly prevalent between the ages of 18 and 34. Despite its frequency in younger groups, less is known about how loneliness specifically affects health and sleep in this age range.
The study used data from the Environmental Risk (E-Risk) Longitudinal Twin Study, a cohort of 2,232 twins born in England and Wales and assessed at ages 18–19. Loneliness was measured using four items adapted from the UCLA Loneliness Scale: how often participants felt they lacked companionship, felt left out, felt isolated from others, or felt alone. Sleep quality over the previous month was assessed with measures that included time to fall asleep, sleep duration, sleep disturbances, and daytime dysfunction such as difficulty staying awake during the day.
About 25–30% of participants reported feeling lonely sometimes, and roughly 5% reported frequent loneliness. The relationship between loneliness and poorer sleep quality persisted even after researchers controlled for depressive and anxiety symptoms, which are known to co-occur with both loneliness and sleep problems.
To explore why loneliness might disrupt sleep, the authors considered the role of perceived safety and past exposure to violence. They examined histories of crime exposure, sexual abuse, child maltreatment, and violent abuse by family members or peers. The association between loneliness and poor sleep quality was markedly stronger — nearly 70% greater — among participants who had experienced the most severe forms of violence. This suggests that a sense of threat or lack of safety may help explain why loneliness can lead to restless sleep.
Biological mechanisms may also play a role. Prior studies indicate that loneliness can alter stress-related systems, including changes in cortisol patterns, which reflect activation of the body’s stress response. Elevated physiological arousal tied to stress could interfere with the ability to fall and stay asleep, contributing to the sleep disturbances observed in lonely individuals.
Professor Louise Arseneault of the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London emphasized the clinical implications: “Poor sleep quality is one of the ways loneliness affects health. Our results highlight the need for early therapeutic approaches that target the negative thoughts and perceptions that can trap people in a cycle of loneliness.”
Professor Arseneault also noted that many participants were university students living away from home for the first time, a life transition that can increase feelings of loneliness. Early support in such settings may help prevent loneliness from escalating into more severe mental health problems.
Timothy Matthews (IoPPN) added that past victimization intensified the link between loneliness and sleep problems. “Feeling unsafe can make restful sleep more difficult, and this is particularly true for people who have experienced violence,” he said. Matthews recommended that clinicians and support services consider both loneliness and a person’s history of victimization when designing interventions.
Study source: King’s College London. The study analyzed data from the Environmental Risk (E-Risk) Longitudinal Twin Study and was published as “Sleeping with one eye open: loneliness and sleep quality in young adults” by T. Matthews, A. Danese, A. M. Gregory, A. Caspi, T. E. Moffitt, and L. Arseneault in Psychological Medicine (published online May 17, 2017).
Abstract (summary)
Feelings of loneliness are common among young adults and are hypothesized to impair sleep quality. Using data from a nationally representative twin cohort of 2,232 individuals aged 18–19, the study assessed loneliness with items from the UCLA Loneliness Scale and sleep quality with the Pittsburgh Sleep Quality Index. Analyses controlled for social isolation, mental health symptoms, employment status, and parenting of an infant. Twin-difference analyses accounted for unmeasured familial and genetic factors.
Loneliness was associated with worse overall sleep quality, especially poorer subjective sleep quality and greater daytime dysfunction. These associations remained after adjusting for covariates and were observed within identical twin pairs, indicating the link is not solely due to shared family background. Importantly, the association was stronger among those with histories of adolescent or childhood victimization.
Conclusion: Loneliness is robustly associated with poorer sleep quality in young people. Early interventions to reduce loneliness and to support those with a history of victimization could help mitigate sleep-related and longer-term health consequences.