Associations between adherence to 24-h movement guidelines and non-suicidal self-injury in adolescents: separate moderation by sex and mediation by psychological health.

Body dissatisfaction can be defined as an attitudinal construct that reflects individuals’ negative evaluations of their overall body, as well as specific aspects of one’s body such as body size, shape, muscularity, and weight (; ; ). Body dissatisfaction is closely linked to a range of negative health consequences and behaviors. For example, in adolescence it is associated with later anxiety and depression episodes (; ), as well as with risk factors for self-injurious thoughts and behaviors (; ), drug-use (), disordered eating behaviors (; ), and smartphone addiction (). For these reasons, body dissatisfaction is considered a serious public health concern. Height dissatisfaction has been identified as an important dimension of negative physical self among Chinese adolescents, with previous studies suggesting that concerns about stature are particularly salient during adolescence (; ). Unlike body weight or body shape, height is largely determined by genetic and developmental factors and is difficult to modify after puberty. Consequently, height dissatisfaction may persist once established and has become a prevalent psychological concern among Chinese adolescents, highlighting the need to better understand its underlying cognitive mechanisms and develop targeted intervention strategies. Cognitive schema theory posits that negative body self-schema drives abnormal attentional processing, which serves as a core mechanism maintaining persistent body dissatisfaction (; ; ). Individuals with negative physical self automatically prioritize schema-congruent negative body information, exhibiting typical attentional vigilance toward negative body cues and difficulty in attentional disengagement from negative stimuli (; ). Empirical studies have confirmed that high body dissatisfaction is closely correlated with implicit attentional bias toward negative body-related information (; ). Correspondingly, adolescents with height dissatisfaction tend to exhibit automatic attentional bias toward height-related negative stimuli, representing a stable implicit cognitive characteristic of height dissatisfaction. However, previous intervention studies have primarily focused on improving explicit body dissatisfaction, with little attention paid to changes in implicit attentional processing. Consequently, it remains unclear whether conventional cognitive-behavioral group counseling can effectively modify implicit height-related attentional bias.