Abstract

This study investigated how childhood attachment trauma influences complex trauma symptoms in young adulthood, focusing on the mediating role of self-system damage and the moderated mediation effect of mentalization. A total of 172 non-clinical emerging adults, aged 18 to 32, who reported experiencing childhood attachment trauma completed self-report online questionnaires. We conducted descriptive statistics, correlation analyses, and conditional process analysis using PROCESS macro Model 14 (Hayes, 2018). The results revealed that childhood attachment trauma significantly increased complex trauma symptoms in early adulthood, with self-system damage identified as a key mediator connecting attachment trauma to complex trauma. Furthermore, the index of moderated mediation was statistically significant, indicating that mentalization played a moderating role in the indirect pathway through self-system damage. Specifically, when self-system damage was low or average, higher levels of mentalization were linked to reduced complex trauma symptoms. Conversely, when self-system damage was high, this protective effect diminished, leading to an increase in complex trauma symptoms. These findings suggest that the role of mentalization may differ based on the level of self-system damage, acting as a conditional moderator that can be either protective or maladaptive depending on self-system stability. The study emphasizes that enhancing mentalization does not provide uniform therapeutic benefits across varying levels of self-system impairment and highlights the need for a staged, developmentally informed intervention approach that prioritizes self-system stabilization in treating complex trauma related to developmental attachment trauma.