Although social media provides a crucial platform for self-development in emerging adulthood, the link between online self-presentation and mental health outcomes remains unclear. Thus, the associations among real self, ideal self, different types of false self-presentations, and depressive symptoms were examined over time (T1–T3) in the present study, along with the mediating role of self-concept clarity. Participants (N = 1,217, Mage = 18.14, 71% female-identifying) completed a survey three times over one year. Random-intercept cross-lagged panel modelling indicated that individuals presenting themselves authentically tended to demonstrate stronger self-concept clarity and fewer depressive symptoms. Those engaging in false-deceptive, compare/impress, and ideal self-presentation tended to have weaker self-concept clarity and more depressive symptoms. A within-person bidirectional association was found between false-deceptive self-presentation and depressive symptoms. Within-person increases in false-explore self-presentation predicted increases in depressive symptoms, whereas increases in compare/impress self-presentation predicted decreases in depressive symptoms. Self-concept clarity was not a significant mediator. The findings suggest that promoting authentic online self-presentation may support self-concept clarity and reduce risk of mental health challenges in emerging adults. However, engaging in false-deceptive online self-presentation (both greater than typical levels and compared to others) may increase risk of mental health challenges, and vice versa.

尽管社交媒体为成年后的自我发展提供了一个重要的平台，但在线自我展示与心理健康结果之间的联系仍不清楚。因此，在本研究中，随着时间的推移 （T1-T3） 检查了真实自我、理想自我、不同类型的虚假自我呈现和抑郁症状之间的关联，以及自我概念清晰度的中介作用。参与者 （N = 1,217，M 年龄 = 18.14,71% 为女性）在一年内完成 3 次调查。 随机截距交叉滞后面板模型表明，真实展示自己的个体往往表现出更强的自我概念清晰度和更少的抑郁症状。那些进行虚假欺骗、比较/印象和理想自我展示的人往往具有较弱的自我概念清晰度和较多的抑郁症状。发现虚假欺骗性的自我表现与抑郁症状之间存在人内双向关联。虚假探索自我呈现的 Within 人增加预测了抑郁症状的增加，而比较/印象自我呈现的增加预测了抑郁症状的减少。自我概念的清晰度不是一个重要的中介因素。研究结果表明，促进真实的在线自我展示可能有助于清晰地实现自我概念，并降低新兴成年人面临心理健康挑战的风险。然而，进行虚假欺骗的在线自我展示（大于典型水平和与他人相比）可能会增加心理健康挑战的风险，反之亦然。