S1 Dataset -

Body checking is a common behavior in both the general population and individuals with body image disturbances. Cognitive-behavioral theories postulate that body checking reduces negative emotions in the short term, but over time contributes to the development and maintenance of eating disorder pathology. So far, few experimental studies have assessed these longer-term consequences, mostly under laboratory conditions, yielding inconsistent findings, and without considering individual vulnerability and specific personality traits. In a naturalistic experimental cross-over design, women with low (n = 76) vs. high (n = 103) body concern completed an online survey on trait characteristics (e.g., intolerance of uncertainty). After a two-day baseline to assess the daily amount of habitual body checking, participants underwent two three-day experimental conditions in randomized order, in which they were asked to exhibit typical vs. threefold increased body checking. Before and after conditions, participants completed state measures of eating disorder symptoms, body dissatisfaction, affect, and general pathology online. In women with high body concern, body image-related symptoms (i.e., drive for thinness, body dissatisfaction) and negative affect worsened in the increased body checking condition, whereas in the typical body checking condition, positive affect increased and no negative impact emerged. Conversely, women with low body concern remained unaffected, except for higher drive for thinness following the increased condition. Bulimic and depressive symptoms did not change in either group. The inclusion of intolerance of uncertainty from an exploratory perspective generally did not impact the results. Our findings regarding the high-risk group underscore the potential etiological relevance of body checking for body image disturbances and eating disorders. For individuals at risk and those already affected by eating disorders, it seems important to address individual body checking as early as possible within psychoeducation to prevent a presumably harmful increase in this behavior. Personality factors influencing vulnerability to body checking need to be further examined.

身体检查（body checking）是普通人群与存在身体意象障碍（body image disturbances）个体共有的常见行为。认知行为理论认为，身体检查可在短期内缓解负面情绪，但长期来看会促进进食障碍（eating disorder）病理的形成与维持。迄今为止，鲜有实验研究评估此类长期效应，且此类研究多在实验室环境下开展，所得结果并不一致，同时未考虑个体易感性与特定人格特质的影响。本研究采用自然实验交叉设计，招募76名低身体关注女性与103名高身体关注女性，让其完成关于特质特征（如不确定性忍受力（intolerance of uncertainty））的在线问卷。在为期两天的基线评估阶段（用于评估日常习惯性身体检查频次）后，参与者被随机分配先后完成两个为期三天的实验条件：分别要求其保持常规身体检查频次，与将身体检查频次提升至原有三倍。在每个实验条件实施前后，参与者均在线完成状态层面的进食障碍症状、身体不满、情绪状态与一般病理状况评估量表。在高身体关注女性群体中，当身体检查频次提升至三倍时，与身体意象相关的症状（即苗条倾向（drive for thinness）、身体不满）与负面情绪均出现恶化；而在常规身体检查条件下，其正面情绪有所提升，未出现负面影响。与之相反，低身体关注女性未出现显著变化，仅在身体检查频次提升后，其苗条倾向得分更高。两组的贪食症状与抑郁症状均未发生变化。从探索性分析角度纳入不确定性忍受力变量后，整体结果并未受到显著影响。针对高风险群体的研究结果证实，身体检查与身体意象障碍及进食障碍的病因学存在潜在关联。对于存在进食障碍风险的个体与已罹患进食障碍的患者，在心理教育中尽早关注个体的身体检查行为，以预防该行为出现有害性增加，这一点尤为重要。影响身体检查易感性的人格因素仍有待进一步研究。