Longitudinal study highlights the enduring toll of childhood loneliness and social isolation

A new study published in Development and Psychopathology indicates that experiencing loneliness during childhood does not help socially isolated youth reconnect with others later on. Instead, childhood loneliness and social isolation independently predict a range of mental health and socioeconomic difficulties in young adulthood. The findings challenge the idea that feeling lonely serves as a helpful biological alarm bell that pushes young people to repair their social bonds.

To understand the study, it helps to distinguish between two related concepts: social isolation and loneliness. Social isolation is the objective, physical reality of lacking positive social relationships and a support network. In childhood and adolescence, this often looks like social withdrawal and peer rejection. Loneliness, on the other hand, is the subjective, internal feeling of being dissatisfied with the quality or quantity of one’s relationships.

A person can be surrounded by peers but still feel lonely, or they can spend a lot of time by themselves without feeling lonely at all. For example, a study covered by PsyPost in 2026 found that teenagers who spend more time in physical solitude are not necessarily lonelier overall, highlighting the difference between temporary alone time and structural social isolation.

Past research has debated how these two social deficits influence one another. A 2013 paper proposed an evolutionary theory suggesting that loneliness acts as an adaptive warning signal, motivating individuals to seek out companionship and escape the dangers of isolation. At the same time, a 2018 study of middle-aged and older adults in Germany found that loneliness and social isolation interacted to predict mortality, with each amplifying the other’s effect.

The research team, led by Bridget T. Bryan and Louise Arseneault of King’s College London, wanted to directly test these competing ideas during the transition from childhood to adulthood.

“Although there is a large body of evidence that loneliness has negative consequences for health and wellbeing, some influential theories suggest that loneliness also serves a useful purpose by motivating socially isolated people to rebuild their social connections,” Bryan, a research fellow at King’s College London’s Social, Genetic & Developmental Psychiatry Centre, told PsyPost. “They argue that loneliness is a bit like hunger: an uncomfortable experience that signals to us that a basic need isn’t being met and motivates us to act on it. In this case, loneliness signals that we have unmet social needs, and pushes us to connect with others.”

“But few studies have tested whether this plays out in the long term, partly because loneliness and social isolation are rarely measured together,” Bryan said. To address this gap, the researchers designed a study to track whether loneliness actually helps isolated children reconnect over time, and whether facing both loneliness and isolation simultaneously creates a magnified penalty for a person’s future well-being. “We also wanted to better understand how loneliness and isolation work together and separately to shape a young person’s health, wellbeing, education and employment as they grow up,” she added.

To do this, the researchers used data from the Environmental Risk Longitudinal Twin Study, which follows 2,232 twins born in England and Wales in 1994 and 1995. The sample is nationally representative, covering a wide range of socioeconomic backgrounds, and consists of 49% male and 90% White participants. The team collected data on the participants at two key developmental stages: age 12 and age 18.

At age 12, the researchers gathered data on social isolation by asking mothers and teachers to rate the children’s social withdrawal and the extent to which they were rejected by peers. The 12-year-olds also filled out a questionnaire to self-report their own feelings of loneliness. At age 18, the participants self-reported both their loneliness and their level of social isolation, which was measured by asking about their access to supportive relationships with family and friends.

The team also assessed a wide array of life outcomes when the participants reached age 18. These included mental health indicators, such as depression and anxiety symptoms. They also measured general well-being, like life satisfaction and sleep quality, along with health behaviors such as smoking and alcohol use. Finally, they evaluated socioeconomic outcomes, tracking the participants’ educational achievements, employability, and whether they were currently out of school and out of work.

The researchers found that loneliness and social isolation feed into each other over time, rather than correcting one another. Children who felt lonely at age 12 tended to be more socially isolated at age 18, and this effect was about twice as strong as the reverse, where children who were socially isolated at age 12 reported higher levels of loneliness as young adults.

This does not support the evolutionary theory that loneliness acts as a helpful alarm bell. Isolated children who experienced high loneliness went on to experience high levels of social isolation as young adults, just like their peers who were isolated but not lonely. The distress of loneliness did not seem to help these youths successfully build or rebuild social connections over the six-year period. “Rather than assuming these children will find their own way through it, our findings suggest loneliness and social isolation may need to be tackled directly,” Bryan noted.

The study also evaluated how these two social deficits impact later life outcomes. Both loneliness and isolation at age 12 independently predicted poorer mental health, worse well-being, and lower socioeconomic standing at age 18. While most mental health links held even after accounting for childhood mental health and personality, childhood isolation’s link to depression and loneliness’s link to anxiety disappeared when these earlier factors were considered. However, childhood social isolation remained linked to every future socioeconomic outcome. “Each mattered in its own right, not just because they tend to occur together,” Bryan explained.

The impact on a participant’s future career prospects proved especially dramatic. “Social isolation was particularly important for education and employment outcomes – more socially isolated secondary school students went on to have fewer qualifications and be less employable in young adulthood than their less isolated peers,” the researcher continued. “The risk of becoming NEET (not in education, employment or training) was particularly striking: the most isolated children had around 2.4 times the odds of being NEET at 18, compared with their peers.”

Interestingly, the researchers did not find evidence of a compounded penalty. Young people who were both highly lonely and highly isolated struggled with similar levels of mental health and socioeconomic difficulties as those who experienced only one of the issues. For well-being and socioeconomic outcomes, the authors described this as a potential ceiling effect. For children who reported the highest levels of loneliness, being socially isolated did not add much extra damage to their well-being or socioeconomic outcomes, possibly because those outcomes were already heavily affected, or because loneliness and isolation work through similar pathways.

Despite this ceiling effect, the sheer impact of isolation alone stood out to the research team. “What surprised us most was the strength of the association between social isolation and poor education and employment outcomes,” Bryan said. “We didn’t expect it to be quite this strong – two to three times stronger than for other well-established risk factors, like childhood depression or anxiety.”

This finding highlights a potential blind spot in how society addresses youth employment. “Given how much public and policy attention youth employment is getting right now, it was striking to find social isolation playing such a large role, when most current strategies focus on skills and job opportunities instead,” she added.

These long-term impacts on mental health are in line with research covered by PsyPost previously. For example, a study covered by PsyPost in 2025 tracked youth into adulthood and found that adolescent loneliness predicted a higher risk for depression and stress-related conditions. In a similar vein, a meta-analysis covered by PsyPost in 2022 highlighted a steady link between youth loneliness and depressive symptoms across different ages and genders. However, while that review measured depressive symptoms at a single point in time, the new study tracked broader mental health longitudinally into young adulthood.

As with all research, there are some caveats to consider. The study measured loneliness and social isolation only at two points in time, separated by six years. This large gap makes it impossible to know if short, temporary bursts of loneliness might act differently than long-term, persistent loneliness. The evolutionary theory suggests that mild, fleeting loneliness might prompt social connection, but this study could not track daily or weekly fluctuations.

The researchers also used different measurement tools at age 12 compared to age 18. This was done to ensure the questions were appropriate for the participants’ changing developmental stages, but it makes it slightly harder to compare their social experiences directly across time.

There are a few things to keep in mind regarding the study sample. Because all participants are twins, their social experiences might look slightly different from those of single children. Twins grow up with a sibling of the exact same age, which could influence how they interact with peers and experience feelings of isolation or companionship.

Going forward, the team hopes to identify the mechanisms that prevent lonely youth from rebuilding their networks. “We’d like to better understand why loneliness doesn’t seem to help isolated children reconnect – for example, whether this is because they withdraw rather than reach out, or because other difficulties that often go along with loneliness (like social difficulties or anxiety) make attempts to reconnect less successful,” Bryan said.

The researchers also want to expand their timeline. “It would also be important to look at how loneliness and isolation relate to each other across different stages of life,” Bryan noted. “Our study focused on childhood and adolescence, but loneliness and social isolation matter at all stages of life.”

The study, “Investigating the interplay of loneliness and social isolation across adolescence: Findings from a nationally representative longitudinal study,” was authored by Bridget T. Bryan, Katherine N. Thompson, Helen L. Fisher, Timothy Matthews, Barry Milne, and Louise Arseneault.