Using nationally representative data from Waves I, II, IV, and V of the National Longitudinal Study of Adolescent to Adult Health (Add Health), Dr. Kim et. al. examined the impact of loneliness during adolescence on health and well-being later in adulthood. Loneliness was measured with a survey question asking how often participants felt lonely in the past week, with response options ranging from “never” to “most or all of the time.” Investigators examined whether this loneliness increased between Waves I and II, when participants were approximately 15 years old. Including covariates, researchers assessed over 40 health outcomes in Waves IV and V, when participants were approximately ages 28 and 37, spanning physical health, behavioral health, mental health, social factors, and civic and prosocial behavior.
The research team found that the participants experiencing more loneliness in their adolescent years had worse mental health outcomes, psychological well-being outcomes, and social outcomes but not physical health outcomes, health behavior outcomes or civic and prosocial outcomes. These results suggest that increases in adolescent loneliness are associated with worsened mental and socio-emotional aspects of adult health. However, because follow-up occurred at relatively young adult ages, additional physical health complications may emerge later in life.
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Kim, Eric S., et al. “Loneliness During Adolescence and Subsequent Health and Well-Being in Adulthood: An Outcome-Wide Longitudinal Approach.” Journal of Adolescent Health, vol. 77, no. 1, July 2025, pp. 66-75. https://doi.org/10.1016/j.jadohealth.2024.12.011.