The pervasive impact of social isolation and loneliness in young people
: An epidemiological, longitudinal and genetically-sensitive study

  • Timothy James Bentley Matthews

Student thesis: Doctoral ThesisDoctor of Philosophy


Several decades of research attest to the importance of social relationships for mental and physical health. Social isolation and loneliness have often been considered adversities associated with aging. However, dissatisfaction with one’s quality or quantity of social relationships is particularly common among young people. This thesis comprises four studies investigating the experiences of social isolation and loneliness in children and young adults, using a longitudinal, genetically-sensitive study design. Data were drawn from the Environmental Risk (E-Risk) Longitudinal Twin Study, a birth cohort of 2,232 twins born in 1994 and 1995. The first empirical chapter investigates associations between social isolation and mental health in the early school years. Longitudinal data from childhood to preadolescence is used to test whether social isolation predicts increases in mental health problems over and above pre-existing difficulties, and vice-versa. The second empirical chapter examines the relationship between social isolation, loneliness and depression in young adults. Behavioural genetic modelling using twin data is used to test the relative contributions of genetic and environmental influences to these associations. The third empirical chapter investigates childhood antecedents of loneliness, and broadly documents the profile of lonely young adults in multiple domains of functioning, including mental health, coping strategies, career prospects and interpersonal perceptions. The fourth empirical chapter analyses the associations between loneliness and aspects of sleep quality in young adults, using the monozygotic twin-differences method to control for familial sources of confounding. A potential exacerbating role of past exposure to violence victimisation on the association between loneliness and sleep is tested. Together, the findings underscore the pervasive role of loneliness in the well-being of young adults, and reinforce the importance of early intervention to prevent its persistence.
Date of Award2017
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorAndrea Danese (Supervisor) & Louise Arseneault (Supervisor)

Cite this