Yohei Sasaki

ABSTRACT Objective The current study aimed to investigate the mediating mechanisms linking adverse childhood experiences (ACEs) to anorexia nervosa (AN) and to examine whether distinct patterns of ACE exposure are associated with differential risks and mediation pathways. Method Data for 9746 female individuals were collected from nationally representative Japanese surveys. ACEs were assessed using a 15‐item Japanese ACE questionnaire, and AN was identified via self‐reported physician diagnosis. Causal mediation analysis and structural equation modelling were used to examine indirect pathways, while latent class analysis (LCA) was used to identify ACE patterns. Results Greater ACE exposure was significantly associated with a higher AN prevalence. In mediation analyses, loneliness, psychological distress, and brooding rumination were the most influential mediators, forming a latent “negative affectivity” factor that significantly mediated ACEs and AN. The LCA identified four ACE profiles: “low adversities”, “psychological abuse”, “poverty”, and “multiple adversities”. Relative to the “low adversities” group, other classes showed higher AN prevalence, although class differences in prevalence and mediators were modest. Discussion We demonstrated that the number of ACEs, rather than their patterns, increases AN risk. Negative affectivity was a consistent strong mediator across ACE patterns; thus, it can be an important target for intervention in trauma‐exposed individuals with AN.