The role of interoception in the overlap between eating disorders and autism: Methodological considerations

Potential mechanisms underlying the association between feeding and eating disorders and autism

There is a reliable association between autism and Feeding and Eating Disorders. Concerningly, where these two conditions co-occur, clinical outcomes of Feeding and Eating Disorders are significantly worse, and treatment less effective, than when the Feeding and Eating Disorders occur in neurotypical individuals. Problematically, the reason for the association between autism and Feeding and Eating Disorders is poorly understood, which constrains advances in clinical care. This paper outlines several possible mechanisms that may underlie the observed association and suggests ways in which they may be empirically tested. Mechanisms are split into those producing an artefactual association, and those reflecting a genuine link between conditions. Artefactual associations may be due to conceptual overlap in both diagnostic criteria and measurement, Feeding and Eating Disorders causing transient autistic traits, or the association being non-specific in nature. A genuine association between autism and Feeding and Eating Disorders may be due to common causal factors, autism directly or indirectly causing Feeding and Eating Disorders, and Feeding and Eating Disorders being a female manifestation of autism.

Profiles of intuitive eating in adults: the role of self-esteem, interoceptive awareness, and motivation for healthy eating

OBJECTIVE

Intuitive eating is an eating behavior that has recently come to use mainly in the young population. Knowing that the Lebanese cultural diet differs from other countries, the purpose of this study was to investigate if there is a relationship between self-esteem, interoceptive awareness, and motivation for healthy eating in a sample of Lebanese adults using a Latent Profile Analysis approach.

DESIGN

Cross-sectional study.

SETTING

Lebanese governorates.

PARTICIPANTS

359 Lebanese participants enrolled in this study (mean age: 22.75 ± 7.04 years, 40.1% males), through convenience sampling in several Lebanese governorates. Participants were asked to fill anonymously the following scales: The Intuitive Eating Scale (IES-2), the Rosenberg Self-Esteem Scale, the Multidimensional Assessment of Interoceptive Awareness Scale (MAIA), and the Motivation for Healthy Eating Scale (MHES).

RESULTS

Our findings revealed four profiles: profile 1 (n = 67; 18.66%) characterized by high SE and intermediate interoceptive awareness and motivation for healthy eating; profile 2 (n = 86; 23.97%) presented high SE, interoceptive awareness, and motivation for healthy eating; profile 3 (n = 86; 23.96%) characterized by high SE, interoceptive awareness, and motivation for healthy eating; class 4 (n = 108; 30.08) described by low SE, intermediate interoceptive awareness, and motivation for healthy eating One-way analysis of variance did not observe a significant difference between the four profiles based on intuitive eating (F = 1.810; p = 0.145; ɳp2 = 0.015).

CONCLUSIONS

Among a sample of Lebanese people, four profiles of interoceptive awareness, motivation for healthy eating, and self-esteem were observed, with no difference concerning intuitive eating.

Sensory processing across eating disorders: A systematic review and meta-analysis of self-report inventories

OBJECTIVE

This review investigated the extant literature regarding the relationship between eating disorder diagnoses and sensory processing as measured by validated and reliable self-report inventories. Increasing evidence highlights the role of sensory processing in cognitive functions. Sensory processing is implicated in mental-ill health, including eating disorders (ED) and body image disturbances. However, the pathophysiological underpinnings of sensory processing, encompassing exteroception and interoception, in relation to ED remain underexplored.

METHOD

We included studies involving participants aged 15 years or older with an eating disorder diagnosis confirmed by semi-structured or structured interviews. We further limited inclusion to articles using validated and reliable self-report instruments to measure sensory processing. Our meta-analysis focused on studies using the interoceptive awareness subscale from the second version of the Eating Disorder Inventory. We used the Critical Appraisal checklist for quasi-experimental studies to assess the quality of included articles.

RESULTS

There were 19 studies that met our inclusion criteria. Most studies showed moderate-to-high quality. Anorexia nervosa (AN) and bulimia nervosa (BN) were associated with heightened exteroception. Moreover, people with AN reported a heightened sense of taste compared to those with BN. Our meta-analysis comprising 10 studies, 19 samples, and 6382 participants revealed that AN (binge-purge subtype) and BN were associated with increased interoceptive difficulties compared to AN (restrictive subtype) or binge-eating disorder.

DISCUSSION

Overall, this review emphasizes the need for a deeper investigation into sensory processing, spanning both exteroception and interoception, in relation to ED. This may prove important for individualizing person-centered care.

PUBLIC SIGNIFICANCE

How people process internal, for example, hunger, and external, for example, taste and sensations is known to influence cognition and mental-ill health, including ED and body image disturbances. However, the ways in which sensory processing may contribute to ED are incompletely understood. We found that individuals with AN or BN experienced heightened exteroception, while people with an eating disorder characterized by purging reported increased interoceptive difficulties. These patterns could inform the development of more personalized treatments.

Is Interoception Deficit Linking Alexithymia and Eating Spectrum Symptoms? Study on a Non-Clinical Sample of Young Adults

We investigated if interoceptive deficits could be the link between alexithymic traits and eating spectrum manifestations in a non-clinical sample. One-hundred sixty-one young adults (mean age: 23.2 ± 2.4 years) were evaluated with the Toronto Alexithymia Scale-20 (TAS-20), the Interoceptive Accuracy Scale (IAS), the Interoceptive Confusion Questionnaire (ICQ), and the Eating Attitudes Test-26 (EAT-26). Questionnaires were administered with an online procedure (Microsoft Form, Office 365 A1, Pisa, Italy) (Study Protocol #0012005/2023). We compared ICQ, IAS, and TAS-20 scores in subjects who met the threshold for a potential eating spectrum disorder according to EAT-26 scores ≥ 20 (n = 27) vs. subjects who scored <20 (n = 134), with an ANCOVA corrected for 'age' and 'gender'. Subjects with EAT-26 ≥ 20, scored significantly higher at ICQ (54.4 ± 13.2 vs. 50.2 ± 6.8; p = 0.011), TAS-20 'Total Score' (60.8 ± 11.9 vs. 58.1 ± 9.2; p = 0.006), and TAS-20 'Identifying Feelings' (21.5 ± 7.6 vs. 17.3 ± 5.8; p = 0.0001). A binary logistic regression analysis, with EAT-26 scores < 20 vs. ≥20 as the dependent variable, and ICQ, IAS, TAS-20 total scores and dimensions, age, and gender (categorical) as covariates, showed that the only variable predicting eating spectrum symptomatology was 'ICQ Total Score' (OR = 1.075, 95% CI: 1.016-1.139; p = 0.013). Interoceptive confusion was the dimension linking the occurrence of alexithymic traits and eating spectrum manifestations.

Introducing a Smart Toy in Eating Disorder Treatment: A Pilot Study

Individuals with eating disorders (EDs) often encounter challenges related to body image, emotional, and sensory difficulties during nutritional rehabilitation. To address these challenges, a novel technology-enabled smart toy, Purrble, designed for immediate assistance in emotion regulation, is being explored. A mixed-method approach involving workshops, diaries, and focus groups was employed to examine the feasibility of Purrble as a therapeutic tool and its impact on participants' daily routines, sensory experiences, and emotional states. The study results demonstrate the engagement and acceptability of this device. Qualitative analysis revealed that participants independently used and integrated Purrble into their emotional and sensory regulation practices. These pilot results support the potential for a shift in the delivery of adjunct therapeutic tools through technology, particularly for ED patients with complex presentations. Future research is necessary to further explore the psychological benefits of this intervention.

"It's not about wanting to be thin or look small, it's about the way it feels": an IPA analysis of social and sensory differences in autistic and non-autistic individuals with anorexia and their parents

BACKGROUND

Despite increasing evidence to support an overlap between autism and anorexia nervosa (AN), underlying mechanisms remain poorly understood. Social and sensory factors have emerged as promising targets in both autism and AN, however there remains scope to compare these differences across autistic and non-autistic experiences of AN. Drawing on dyadic multi-perspectives, this study explored experiences of social and sensory differences in autistic and non-autistic adults and their parents and/or carers.

METHODS

Using interpretative phenomenological analysis (IPA), dyadic interviews were conducted with 14 dyads, with seven autistic dyads and seven non-autistic dyads. Data analysis was subjected to a triangulation of interpretations: (1) the participants themselves; (2) a neurotypical researcher; (3) and an Autistic researcher with lived/living experience of AN.

RESULTS

IPA identified three themes in each group, with similarities and differences between autistic and non-autistic dyads. Similar themes were identified regarding the importance of social connectedness and socio-emotional difficulties, as well a common lack of trust in the social and sensory self and body. Autism-specific themes centred on feelings of social 'defectiveness', disparities between sensing and expressing certain cues, and lifelong, multi-sensory processing differences. Non-autistic themes reflected social comparisons and inadequacy, and sensitivities to the learning of ideals and behaviour through early experiences.

CONCLUSIONS

While similarities were observed across both groups, there appeared to be notable differences in the perceived role and influence of social and sensory differences. These findings may have important implications on the delivery and modification of eating disorder interventions. Specifically, they suggest that while treatment targets may look similar, subtle differences in underlying mechanisms and approaches may be required for Autistic individuals with AN across sensory, emotion and communication-based interventions.

Effects of chronic psychosocial stress on 'binge-like' sucrose intake in mice

Binge eating episodes are persistent and are essential features of numerous eating disorders (EDs). Susceptibility to EDs is largely presumed to be associated with early life stress. In fact, converging evidence from preclinical animal studies have implicated stress as a driver of binge eating. Still, literature examination indicates that vulnerability to EDs may depend on factors such as severity, time, and the type of stressor. Therefore, we aimed at exploring the link between chronic psychosocial stress and 'binge-like' sucrose intake in adolescent mice. To this aim, intruders' experimental mice were exposed to the chronic subordinate colony (CSC) housing, in the presence of a resident aggressive mouse for 2 weeks. At the end of the stress period, mice were tested for anxiety-like behavior then assessed for 'binge-like' intake of sucrose using a long-term drinking in the dark (DID) method that successfully replicates binge eating in humans. As expected, and compared to single housed colony controls (SHC), CSC exposure elicited an anxiogenic-like response in the open field (OF) and elevated-plus maze (EPM) tests and reduced weight gain. Most importantly, we report here for the first time, that mice exposed to chronic psychosocial stress displayed a 'binge-like' consumption of sucrose. However, neither quinine (bitter) nor saccharin (sweet) intakes were affected by CSC exposure. Finally, using Pearson's correlation, results showed a strong correlation between anxiety-like behavior parameters and sucrose intake. Overall these findings support the validity of our chronic psychosocial stress to model binge EDs and establish the long-term consequences of stress on 'binge-like' eating in male mice. These data suggest that chronic psychosocial stress is a risk factor for developing anxiety-associated EDs.

Is Alexithymia the Link Between Anorexia and Autism Spectrum Disorders?

Objective

Alexithymia main features include deficits in empathy, emotion recognition and regulation. Alexithymia has been recently proposed as a potential key to explain the presence of the so-called 'autistic spectrum disorder' signs (ASD), in patients with Anorexia Nervosa (AN). Objective of this review is to summarize current knowledge on the potential role of alexithymia in linking ASD and AN.

Method

A systematic search has been conducted on PUBMED database of the last 10 years, in accordance with PRISMA Guidelines, applying queries in the 'PubMed Advanced Search Builder'.

Results

We initially retrieved 18 papers; the final selection has led to seven papers. According to the available studies, alexithymia is widely represented in samples of AN patients and comorbid ASD traits. However, the specific load of alexithymia in AN with ASD features is still in debate, as well as the potential role of interoceptive deficits. We have found several limitations in the reviewed studies, which shared a cross-sectional design, with no comparison between a pre and a post-treatment condition (except for one study), small samples sizes and some heterogeneity of administered instruments.

Conclusions

the specific load of alexithymia in explaining the link between AN and ASD is still in debate. Interoception deficit has been proposed as having a crucial role. Further research should be devoted to longitudinal studies and not only to cross-sectional observations.