The effect of Loneliness on Suicidal Ideation in Adolescents: The Mediating Role of Depression and the Moderating Role of Hope

Objective Adolescents are particularly vulnerable to developing suicidal ideation during this critical developmental stage due to emotional dysregulation and interpersonal difficulties, which in turn increases the risk of suicide. Therefore, it is essential to identify the factors and underlying mechanisms that contribute to suicidal ideation. This study aims to investigate the relationship between loneliness and suicidal ideation in Chinese adolescents, focusing on the mediating role of depression and the moderating effect of hope. Methods Participants in this study included 4,498 adolescents from several middle and high schools in two urban areas in central China (Mage = 13.91, SD = 1.57; 2,418 boys, 2,080 girls). These adolescents completed surveys measuring loneliness, depression, hope, and suicidal ideation. Correlation analysis, mediation analysis, and moderation analysis were conducted using SPSS software and the PROCESS plugin. Results The results indicated that: (1) loneliness significantly positively predicted suicidal ideation in adolescents; (2) depression partially mediated the relationship between loneliness and suicidal ideation; and (3) hope significantly moderated both the first and second pathways in the mediation model. Specifically, when hope was higher, loneliness significantly reduced depression, which in turn lowered the risk of suicidal ideation; conversely, when hope was lower, this predictive relationship was significantly strengthened. Conclusion This study further elucidates the underlying mechanisms through which loneliness influences suicidal ideation in adolescents and confirms that this mechanism is moderated by hope. These findings offer valuable insights for mental health professionals in the prevention and intervention of adolescent suicide and have important practical implications.