Loneliness and Bullying by Siblings in Gender-Diverse Adolescents: Results From the Population-Based Generation R Study

Objective: Gender-diverse individuals often face a burden of poor mental health. This study examined whether gender-diverse experiences were associated with higher levels of loneliness in adolescents, over and above depression and anxiety, and how family environmental factors, including maladaptive parenting, being bullied by a sibling at home (victimization), and bullying a sibling at home (perpetration), moderate the associations between gender-diverse and loneliness experiences among 4,424 adolescents in a population-based cohort. Method: This cross-sectional study was embedded in Generation R, a multiethnic population-based cohort from fetal life onward. Adolescents with information on self-reported or parent-reported gender diversity and loneliness at ages 13 to 15 years were included. Results: Adolescents who reported gender diversity had higher levels of loneliness compared with youth who did not report gender diversity (assigned female at birth: B = .67, 95% CI 0.49-1.23; assigned male at birth: B = .45, 95% CI 0.32-0.98). The associations remained after taking into account depression and anxiety, indicating a unique association of gender diversity with lonely feelings in adolescence (assigned female at birth: B = .38, 95% CI 0.24-0.51; assigned male at birth: B = .31, 95% CI 0.17-0.46). Being bullied by a sibling at home (victimization) modified the association of gender diversity with loneliness experiences (interaction p = .04). No evidence was found for interaction effects between gender diversity, maladaptive parenting, and any temperamental traits on adolescent loneliness (ps > .10). Conclusion: Gender diversity is associated with higher levels of loneliness in adolescents. Being a target of bullying modified the association of gender diversity with loneliness experiences, suggesting that gender-diverse adolescents who are bullied by siblings experience particularly higher levels of loneliness. Plain language summary: Gender-diverse youth experience substantial mental health disparities when compared to cisgender youth. This cross-sectional study examined how gender diversity related to loneliness in adolescents, finding higher loneliness levels among gender-diverse youth, independent of depression and anxiety. Sibling bullying—not maladaptive parenting or temperamental traits—was associated with higher levels of loneliness. These findings emphasize modifiable risk factors and the need for targeted support in family and social environments.