Although it is thought that eating disorders result from the interplay of personal and sociocultural factors, a comprehensive model of eating disorders remains to be established. The aim of this study was to determine the extent to which the childhood factors and deficit in visuoperceptual ability contribute to eating disorders.
A total of 76 participants - 22 women with anorexia nervosa (AN), 28 women with bulimia nervosa (BN), and 26 healthy women of comparable age, IQ, and years of education - were examined. Neuropsychological tasks were applied to measure the visuoperceptual deficits, viz. the Rey-Osterrieth complex figure test and the group embedded figures test (GEFT). A questionnaire designed to obtain retrospective assessments of the childhood risk factors was administered to the participants.
The women with both AN and BN were less likely to report having supportive figures in their childhood and poor copy accuracy in the Rey-Osterrieth test. The women with AN were more likely to report premorbid anxiety, childhood emotional undereating and showed poor performances in the GEFT. In the final model, the factors independently contributing to the case status were less social support in childhood as a common factor for both AN and BN, and childhood emotional undereating and poor ability in the low-level visuospatial processing for AN.
Our results suggest the disturbance in the food-emotion relationship and the deficit in low-level visuospatial processing in people with AN. Lower social support appears to contribute to an increase in vulnerability to both AN and BN.
The aetiology of eating disorders is complex, with genetic, biological, psychological and sociocultural factors appearing to contribute significantly to their susceptibility.
There have been a number of studies which examined the role of developmental factors in predicting the onset of eating disorders and their results were summarized in systematic reviews.
We aimed at the development of coherent model of eating disorders including comprehensive childhood risk factors and visuospatial dysfunction. Thus the present study was designed to answer the following questions; To what extent do childhood risk factors contribute to eating disorders and what is their relative importance between AN and BN?: What are the detailed profiles of visuospatial impairment in AN and BN?: What is the comprehensive model consisting of both childhood risk factors and visuospatial deficit in AN and BN? The main hypothesis was that patients with AN and BN have certain risk factors in common and that both of them have an impairment of visuospatial ability, but that the pattern of impairment might differ. To test those hypotheses, we chose two neuropsychological tests, the Rey-Osterrieth Complex Figure Test
A total of 76 participants, including 22 women with AN and 28 women with BN as well as 26 healthy women, were recruited. The diagnoses of eating-disorder patients were as per the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria using the Korean version of the Structured Clinical Interview for DSM-IV Axis I disorders (SCID).
We matched the groups in terms of general intelligence ability and years of education, administering the Korean version of the Wechsler Adult Intelligent Scale
The questionnaire focused on the period before onset of eating disorders to ensure that the exposure preceded the development of the eating disorder. The questionnaire comprised 36 questions, divided into 8 domains which covered (i) Parents or adults concern about thinness (ii) Parents or adults teasing about weight or shape (iii) Social support (iv) Anxiety (v) Perfectionism (vi) Emotional overeating (vii) Emotional undereating (viii) Picky eating. The psychometric properties of the Korean version was assessed with 2 week test-retest reliability for the 8 factors ranging between 0.64 and 0.87, and Cronbach's alpha coefficient ranging between 0.70 and 0.91.
We applied the group version of the EFT
The Rey-Osterrieth Complex Figure Test
The three groups (AN, BN, controls) were compared in terms of their clinical variables using analysis of variance and t-tests, as appropriate for the measurements. Multinomial logistic regression with the independent variables consisting of the childhood risk factors, RCFT and GEFT was used to identify those factors which have an impact on the group membership, with the controls used as a reference group. We used multivariate logistic regression analyses using the forward variable selection strategy on the putative factors, in order to find those factors independently contributing to the case status. Two-tailed tests with a 5% level of significance were used throughout the analyses.
As shown in
The identified neuropsychological variables and childhood risk factors obtained from the univariate analyses were entered into the regression model analyses (
This study furthers our understanding of the aetiological model of eating disorders. In our study, the AN patients were more likely to report childhood emotional undereating and performed poorly on GEFT. Both the AN and BN patients were more likely to report lower social support, which factors appear to contribute to an increase in vulnerability to eating disorders case status.
Emotional eating involves integrated emotional regulation, reward processing, and interoception. In our retrospective study, childhood emotional undereating strongly contributed to AN case status, which supports the idea of a trait-related dysfunction in the brain appetite circuit in AN, as proposed by Kaye et al.
In the neuropsychological data, our findings are consistent with previous studies of poorer performance on GEFT in AN,
However, the present study contained a few limitations, which need to be considered. The first is the retrospective assessment of the risk factors. Although we carefully assessed the risk factors with a focus on the period of childhood before the onset of the patients' disorders, to ensure that the period of risk factor exposure preceded the eating disorder's development, such soft judgments as over-concern and expectations may be biased by retrospective recall or affected by the patient's current state. Second, we might not have included all of the risk factors relevant to a more comprehensive neurodevelopmental hypothesis, i.e., perinatal events. Third, we could not use more comprehensive tasks as measures of visuospatial ability. Fourth, the sample size was relatively small.
In conclusion, these findings add to the growing body of evidence for a complex etiological model of eating disorders. Our results suggest that the disturbance in the food-emotion relationship and the deficit in low-level visuospatial processing in people with AN. Lower social support appears to contribute to an increase in vulnerability to both AN and BN.
We wish to thank Drs Carolina A López and Amy J Harrison for their advice on the study. A Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2006-331-E00203) supported this work.
The clinical and demographic characteristics of the study population
Data are shown as means (standard deviation). Analysis was by ANOVA or t-test as appropriate. *p<0.05, †p<0.01 in post-hoc Tukey test, as contrasted with controls. AN: Anorexia Nervosa, BN: Bulimia Nervosa, WAIS: Wechsler Adult Intelligent Scale, STAI: State and Trait Anxiety Inventory, MOCI: Maudsley Obsessive and Compulsive Inventory, EDE: Eating Disorders Examination Interview, n/a: not associated
Comparisons of the retrospective childhood risk factors in the AN and BN patients and the healthy controls
Data are shown as mean (standard deviation). The likelihood ratio statistic, χ2 (with 2 df) and its p value are given for each variable, with the healthy controls used as a reference group. *indicate odds ratios that were significantly different from 1, according to Wald tests. AN: anorexia nervosa, BN: bulimia nervosa, CI: confidence interval
Comparisons of the visuospatial ability of the AN and BN patients with the healthy controls
Data are shown as mean (standard deviation). The likelihood ratio statistic, χ2 (with 2 df) and its p value are given for each variable, with the healthy controls used as a reference group. *indicate odds ratios that were significantly different from 1, according to Wald tests. AN: anorexia nervosa, BN: bulimia nervosa, CI: confidence interval, GEFT: group embedded figures test, RCFT: Rey-Osterrieth complex figure test
Factors independently affecting case status compared with healthy controls in final model
Low-level of visuospatial processing was derived from the group embedded figures test. Copy accuracy was from the Rey-Osterrieth complex figure test. *odds ratio (95% CI) was shown using forward selection in the regression analyses model. AN: Women with anorexia nervosa, BN: Women with bulimia nervosa, CI: confidence interval