Nonsuicidal self-injury (NSSI) and negative body image are both highly prevalent among adolescents, and there are theoretically proposed reciprocal associations between them. However, previous research has not differentiated between stable personal traits and time-varying state levels when examining these associations, and the underlying mechanisms remain unclear. To address these gaps, this study investigated the longitudinal associations between negative body image, self-disgust, and NSSI among Chinese adolescents, disentangling the between- and within-person effects by employing random intercept cross-lagged panel models (RI-CLPMs). A total of 515 Chinese adolescents (50.7% boys
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