| 其他摘要 | Eating disorders are severe mental disorders which are characterized by persistent disturbances in eating or eating-related behaviors. Anorexia nervosa (AN) and bulimia nervosa (BN) are two common subtypes of eating disorders. Patients with AN or BN are often obsessed with and overvalue weight and body shape, accompanied by distorted body perception. Previous studies have pointed out that patients with AN or BN often overestimated own body size which have been linked to one key symptom of eating disorder, namely fear of fat. A related question is how patients with AN or BN perceive the body of others. The answer to this question is important since it will shed light on whether abnormal visual processing also contributes to their distorted body image, over and above those could be explained by fear of fat. In addition, concerns about weight and body shape are not only existed in patients with eating disorders, many young females also wish to have a thinner body, while drive for thinness is an known risk factor for eating disorders. Thus, how those with the willingness to be thin perceive own and other's body? Do they have shared features with patients with eating disorders when perceiving own and other's body? The present study aimed to explore these issues.
Study 1 aimed to investigate how patients with AN or BN perceive other's body by enrolling 34 patients with AN，15 patients with BN, and 56 matched healthy controls. Participants were asked to judge the height and weight (to calculate the estimated BMI) and to rate the attractiveness of 126 photo models (63 female and 63 male). Eating disorder symptomology were assessed by the self-reported Eating Disorder Examination Questionnaire 6.0. The results showed that: (1) Compared with the healthy controls, patients with AN or BN provided significantly lower BMI estimates of the photo models, especially for female photo models; (2) The two patient groups rated the attractiveness of photo models lower than healthy controls did, and also tended to gave higher attractiveness ratings to thinner body and lower attractiveness ratings to heavier body than healthy controls; (3) The attractiveness ratings to photo models were positively correlated with participants' disordered eating symptomology. The findings suggested that patients with AN or BN may have abnormal visual body perception. The findings also showed that patients' preference for a thinner body is not limited to own body, namely thinness is a very important criterion for attractiveness rating of other's body.
Drive for thinness is an known risk factor for eating disorders. In study 2, three experiments were designed to capture how female adolescents with the willingness to be thin perceive own and other's body. Experiment 1 aimed to explore whether their estimates to own and others' body size were accurate; Experiment 2 aimed to examine the relationship between their body size estimates and the severity of disordered eating symptomology; Experiment 3 aimed to study whether their features of body perception were temporally stable. Experiment 1 included the young females with the willingness to be thin(n=91) and their counterparts without such wish (n=88). Each participant was asked to use a rope to estimate the circumference of the arm, waist and thigh of themselves and their experimental female partner. The results showed that female adolescents with the willingness to be thin overestimated own and partner's body parts, which was similar to the findings previously reported among patients with eating disorders. Hierarchical regression analysis showed that (1) the estimates to experimental partner's body parts could significantly predict the estimates to own body parts, indicating that the overestimation of their own body parts could be partly explained by the abnormal visual perception process; (2) After controlling BMI and the estimates to experimental partner's body, their willingness to be thin could significantly predict the estimate to own body parts, indicating that the overestimation of own body parts was affected by body image attitude.
Experiment 2 recruited 86 female adolescents with the willingness to be thin. Their disordered eating symptomology was assessed by the self-reported Eating Disorder Inventory. Experiment 2 repeated findings in Experiment 1，namely those young females with the willingness to be thin did overestimate own body size, and further revealed that the estimates to own waist was positively correlated with scores on Eating Disorder Inventory, indicating that the overestimation of own body size was related to disordered eating symptomology.
Some of the participants (n=36) in Experiment 1 were invited to participate in Experiment 3 after four months二They completed the same experimental procedure as in Experiment 1 .It was found that the body size estimates to own and other's body had good temporal stability, indicating that body perception features of those at risk of eating disorders may be more trait-like than state-like. Additionally, majority of participants in the three experiments of Study 2 set an ideal weight in the underweight range.
The current study found that patients with eating disorders and individuals with desire for thinness showed abnormal body perception, and suggested body perceptual features may be a cognitive marker to used in the early identification of eating disorders. Additionally, among Chinese female adolescents, the proportion with the willingness to be thin is high, and their desire to be thin is strong, which may endanger their physical and mental health if keep unwatched. Therefore, it is necessary to pay attention to body image and related problems among Chinese adolescents. |
修改评论