The impact of theory of mind and neurocognition on delusionality in anorexia nervosa

Affective cognition in eating disorders: a systematic review and meta-analysis of the performance on the "Reading the Mind in the Eyes" Test

BACKGROUND

The Reading the Mind in the Eyes Test (RMET) is listed in the National Institute of Mental Health's Research Domain Criteria as a tool apt to measure the understanding of others' mental states. People diagnosed with anorexia nervosa (AN) showed poorer performances on the RMET than healthy controls. Less data are available concerning other eating disorders.

METHODS

Systematic review of four major databases from inception to July 15, 2021 following the PRISMA guidelines. Meta-analysis of cross-sectional observational studies comparing the scores of the RMET between patients with eating disorders and age- and-gender matched control groups.

RESULTS

Out of 21 studies, we retrieved 29 independent samples of patients diagnosed with an eating disorder. Patients with active AN (n = 580) showed worse performances on the RMET than controls (n = 1019). Year of publication accounted for 61% of the (substantial: I² = 81%) heterogeneity in the meta-analysis. Earlier studies were more likely to find worse performances on the RMET of patients with active AN than later studies. Patients with bulimia nervosa (n = 185) performed poorly as compared to controls (n = 249), but the results were not statistically significant on the random-effect model. Obese patients with binge-eating disorder (n = 54) did not differ on the RMET from obese controls (n = 52). Patients with eating disorder not otherwise specified (n = 57) showed minimal differences compared to controls (n = 96). Study quality was good in six studies only.

CONCLUSIONS

Patients with eating disorders do not suffer from an impaired understanding of others' mental states, except for a still-to-be-identified subgroup of patients with active AN.

LEVEL OF EVIDENCE

I, systematic review and meta-analysis.

Phonological working memory is adversely affected in adults with anorexia nervosa: a systematic literature review

PURPOSE

Cognitive restraint has potentiating and deleterious effects on working memory (WM) in anorexia nervosa (AN). Conflicting evidence may be due to heterogeneity of tasks examining different WM components (e.g., verbal/auditory versus visuospatial), and differences in adolescent versus adult AN. Additionally, differential cognitive profiles of restricting versus binge/purging subtypes, comorbid psychiatric disorders and psychotropic medication use may confound findings.

METHODS

To address these conflicts, 25 studies, published between 2016 and 2021, investigating WM in children, adolescents and adults with AN were systematically reviewed using PRISMA guidelines.

RESULTS

In 71% of WM tasks, no difference in performance between AN patients and age-matched controls was reported, while 29% of WM tasks showed worse performance. Adults with AN displayed deficits in 44% of the verbal/auditory tasks, while performance remained unaffected in 86% of visuospatial tasks.

CONCLUSION

Examining age groups and WM subsystems separately revealed novel findings of differentially affected WM components in AN. Comorbidities and psychotropic medications were common among AN participants and should be regarded as critical confounding factors for WM measures. Future studies examining different components of WM, acknowledging these confounding factors, may reveal specific deficits in AN to aid treatment improvement strategies.

LEVEL OF EVIDENCE

I, systematic review.

Distinguishing delusional beliefs from overvalued ideas in Anorexia Nervosa: An exploratory pilot study

BACKGROUND

Characterised by the belief that more weight needs to be lost-despite emaciation, failing organs, medical instability and prospect of death-Anorexia Nervosa (AN) is a condition in which irrational, and highly-skewed, beliefs can be of delusional intensity. However, the nexus between delusion and rational awareness and how this is related to body image acceptance and perception has yet to be examined in AN. The current study aims to investigate the relationship between body dissatisfaction and beliefs of delusional intensity in an adult AN inpatient sample.

METHODS

Twenty-one adults (n_(women) = 20; n_(men) = 1), with a mean age of 27 years old (SD = 10), presenting for inpatient treatment for AN (ranging in severity from mild to severe; M_{(Body Mass Index)} = 17 kg/m²; M_{(Length of Stay)} = 22 days) participated in the study. Participants' dominant beliefs (related to AN) and level of insight (delusional; overvalued idea; or fair insight) were measured using either the Brown Assessment of Beliefs Scale (BABS) or the Nepean Beliefs Scale (NBS). The degree of body dissatisfaction was determined by examining the discrepancy between "perceived" and "ideal" body perception. To determine subjective and objective beliefs both the Contour Drawing Rating Scale (subjective) and computerised Body Image Assessment Software (objective) were used.

RESULTS

Almost one quarter (23.7%; n = 5) of participants appeared to have beliefs of delusional intensity related to their body shape (M = 27.4; SD = 23.03). Although a positive linear trend was indicated, there were no significant differences in body dissatisfaction scores between level-of-insight. Individuals whose belief was categorised as delusional were more likely to hold a negative affective body image state based on their ratings on the body image state survey when compared to the group who had good/fair insight (95% CI [0.53, 18.19]; p = 0.03).

CONCLUSIONS

The current exploratory pilot study concurs with others in the published literature that demonstrate that approximately 25 percent of participants with AN may have delusional ideas. The implications for treatment in similar samples warrant attention. Future research should also seek to understand the clinical significance of this delusional categorisation, the benefits of its utility in this population, and its relation to the severity of AN or stage of illness.

Development and validation of the schedule for the assessment of insight in eating disorders (SAI-ED)

This study examined the reliability, validity and internal structure of the newly developed, interview-based Schedule for the Assessment of Insight in Eating Disorders (SAI-ED) and the relationships of insight with demographic and clinical characteristics in EDs. Ninety-four female patients - 44 with anorexia nervosa (AN) and 50 with bulimia nervosa (BN) - were assessed with SAI-ED. The Brown Assessment of Beliefs Scale was used to evaluate convergent validity of SAI-ED. Hierarchical cluster analysis and multidimensional scaling were used to identify insight components and assess their inter-relationships. The final 8-item SAI-ED demonstrated good psychometric properties. Inter-rater and test-retest reliabilities were high. Three subscales of SAI-ED were identified which measure major insight components: awareness of illness, awareness of symptoms, and treatment engagement. Patients with AN had significant lower score on SAI-ED than patients with BN. Impaired insight was associated with: (a) lower current and lowest lifetime BMI and more severe dietary restrain in AN, (b) illness duration, severity of overall ED symptoms, body-related concerns and obsessionality in BN. Insight is a multidimensional construct in EDs associated with different clinical aspects in AN and BN. The SAI-ED is a valid and reliable tool for the assessment of insight in EDs patients.