Impact of loneliness on depression among cancer survivors: a comparison between adolescents and young adults and other age groups

Numerous studies have suggested an association between loneliness and depression in cancer survivors, particularly adolescents and young adults (AYAs). This study aimed to develop a causal model linking loneliness to depression using structural equation modeling. A cross-sectional web-based survey was conducted to collect demographic information and psychosocial measures, including the UCLA Loneliness Scale, Patient Health Questionnaire-9, EQ-5D-5L, Multidimensional Scale of Perceived Social Support short form, Brief Resilience Scale, Comprehensive Score for Financial Toxicity, and a single item on cancer-related stigma. Structural equation modeling with observed variables was conducted, focusing on the pathway from loneliness to depression. Multiple-group analysis was used to compare AYAs and non-AYAs. The study included 3,565 cancer survivors, of whom 743 (20.8%) were AYAs. The final model showed a significant association between loneliness and depression (standardized coefficient = 0.214; 95% confidence interval = 0.184–0.243; P < 0.001). Perceived social support, resilience, financial toxicity, and stigma were directly or indirectly related to loneliness and depression. Female sex and having a spouse or partner were associated with perceived social support, whereas non-job-related social participation was associated with loneliness. The association between loneliness and depression was significantly stronger among AYAs than non-AYAs. The results suggested a significant link between loneliness and depression, with a stronger pathway in AYAs. Loneliness may serve as a modifiable mediator for interventions targeting depression prevention among AYA cancer survivors. The psychosocial variables identified could aid in screening high-risk individuals and developing effective interventions.