Assessing the relationship between eating disorder psychopathology and autistic traits in a non-clinical adult population

Weak central coherence, cognitive rigidity and disordered eating in a community sample

Recent evidence has highlighted that a moderate degree of disordered eating has become the norm among the general population. While previous research has demonstrated that individuals with eating disorders exhibit heightened weak central coherence (i.e., attention to detail) and cognitive rigidity, and this plays a key role in the development and maintenance of the disorders, less is known about the relationship between disordered eating and these cognitive styles in subclinical community samples. A community sample of females completed self-report measures of weak central coherence, cognitive rigidity and eating disorder pathology. Unlike previous studies in the area, we first excluded participants with a diagnosis of eating disorder and then confined the analyses to those without clinically significant disordered eating. In line with the clinical literature, we found both cognitive rigidity and weak central coherence to correlate with severity and frequency of disordered eating behaviours and cognitions, suggesting the relationship also exists in subclinical samples. If replicated and expanded upon, these findings may bear important implications for the prevention and early identification of disordered eating in the community.

Exploring the role of autistic traits and eating disorder psychopathology on mentalising ability in the general population

BACKGROUND

This study evaluated the role of overlapping traits and characteristics related to autism spectrum disorder (autism) and anorexia nervosa (AN) in the general population, and the impact of these traits on mentalising ability.

METHODS

A sample of young adults (N = 306), aged 18-25 years, was recruited to complete an online study that consisted of 4 measures: the Autism-Spectrum Quotient, Eating Disorder Examination Questionnaire, the Mentalization Scale, and the Reading the Mind in the Eyes task.

RESULTS

Higher levels of autistic traits, particularly difficulty with attention switching, were associated with increased eating disorder psychopathology. Overall, autistic traits and eating disorder psychopathology were related among females, but not males. Difficulty with attention switching, however, was related to eating disorder psychopathology among both females and males. Autistic traits also appear to have a greater role in mentalising ability than does eating disorder psychopathology.

CONCLUSION

The role of attention switching in overlapping traits of autism and eating disorder psychopathology needs to be more comprehensively evaluated by future research, as does the role of biological sex. Expanded knowledge in this field will help to better understand and evaluate symptoms at presentation, leading to clearer diagnoses and potentially better treatment outcomes.

Autistic traits distribution in different psychiatric conditions: A cluster analysis on the basis of the Adult Autism Subthreshold Spectrum (AdAS Spectrum) questionnaire

Increasing interest is being paid on full-threshold and sub-threshold autism spectrum conditions among adults. Sub-threshold autistic traits (AT) seem to be distributed in a continuum from the clinical to the general population, being particularly higher among subjects with other psychiatric disorders. The aim of the present study was to evaluate the distribution of AT in a sample of subjects with different psychiatric conditions by means of a cluster analysis on the basis of the score reported to the AdAS Spectrum instrument. A total of 738 subjects recruited by seven Italian Universities were divided in 5 groups depending on the clinical diagnosis: Autism spectrum disorder (ASD), subthreshold ASD symptoms (partial ASD), Bipolar disorder (BD), Feeding and eating disorders (FED), and controls (CTLs). All subjects were assessed with the AdAS Spectrum. The cluster analysis identified 3 clusters: the high, medium and low autism clusters. The Restricted interests and rumination domain reported the highest influence in forming the clusters. The high, medium and low autism clusters were respectively more represented in the ASD, partial ASD and CTL groups. The clusters were represented intermediately in the FED and BD groups, confirming the presence of intermediate levels of AT in these clinical populations.

Investigating the relationship between orthorexia nervosa and autistic traits in a university population

BACKGROUND

Orthorexia nervosa (ON) is an emerging condition featuring restrictive eating behaviors on the basis of subjective beliefs about food healthiness. Many authors have stressed the similarities between ON and anorexia nervosa (AN) in both cognitive and behavioral patterns. Despite that, while the link between AN and female autism presentations is well known in the literature, no study has yet investigated the relationship between ON and autism spectrum. This work aims to investigate the relationship between ON and autistic traits in a university population.

METHODS

An e-mail invitation was sent to all the students and University workers of University of Pisa. Subjects were asked to fulfill the ORTO-15 and the Adult Autism Subthreshold spectrum (AdAS spectrum) questionnaires.

RESULTS

A total of 2426 subjects joined the survey: 623 subjects (26.3%) reported a score associated with significant orthorexic symptoms according to ORTO-15 (ON group), while 1789 subjects (73.7%) did not report ON symptomatology and were considered as healthy controls (HC). The ON group scored significantly higher on almost all AdAS spectrum domains. Moreover, being female and scoring higher on AdAS spectrum were statistically predictive factors for the presence of ON symptomatology. Among AdAS spectrum domains, higher scores on AdAS spectrum inflexibility and adherence to routine and restricted interests and rumination domains, as well as lower scores on verbal communication domain, were statistically predictive of orthorexic symptoms.

CONCLUSIONS

Our findings highlight an overlap between ON and autism spectrum psychopathology. Further studies are needed to clarify the relationship between restrictive eating disorders and female autism phenotypes.

Eating disorders and autism spectrum: links and risks

In the last decades, increasing attention has been provided to socio-cultural and neurobiological factors involved in the psychopathology of feeding and eating disorders (FED), encouraging a multifactorial approach. In this framework, several authors stressed an association between FED and other kinds of psychiatric disorders from both a psychopathological and a neurobiological point of view. In particular, many promising contributions are focusing on the possible link between FED and autism spectrum disorder (ASD). Growing interest about this association rose from the frequently reported evidence of ASD-like traits amongst FED patients and abnormal eating behaviors amongst patients with ASD. This narrative review overview aims to summarize the most relevant findings about the overlap between different kinds of FED and the autism spectrum, taking into account the most recent hypotheses about the psychopathology of both these conditions. While most of the studies focused on anorexia nervosa, both ASD and autistic traits seem to be detectable also in other kinds of FED. In addition, the recently increased interest toward a dimensional approach to psychopathology led to progressively broadening the concept of ASD, focusing on its subthreshold and gender-specific manifestations and on its link with other psychiatric conditions, including FED. Globally the studies summarized here provide further support to theoretical models featuring a neurodevelopmental approach for mental disorders. In particular, FED have been conceptualized as a possible psychopathological trajectory of a neurodevelopmental alteration, toward which female gender would act as one of many predisposing factors.

The Association Between Autistic Traits and Disordered Eating is Moderated by Sex/Gender and Independent of Anxiety and Depression

Previous studies have reported positive correlations between autistic traits and disordered eating, though it is unclear whether the association is moderated by sex/gender or whether it is independent of anxiety or depression. We present the findings of an online survey of 691 participants who completed the Autism Spectrum Quotient (AQ), Hospital Anxiety and Depression Scale (HADS), and Eating Attitudes Test-26 (EAT-26). Following a pre-registered analysis plan, we observed positive correlations between AQ and EAT-26 in males and females, with the association being significantly stronger in females. AQ also remained a significant predictor of EAT-26 when anxiety and depression were controlled for statistically. These findings may be relevant when considering therapeutic interventions in disordered eating populations that exhibit autistic traits.

Prevalence of autism spectrum disorder and autistic traits in children with anorexia nervosa and avoidant/restrictive food intake disorder

BACKGROUND

Autism spectrum disorder (ASD) and feeding and eating disorders (FEDs) such as anorexia nervosa (AN) are strongly linked as evidenced by frequent comorbidity and overlapping traits. However, eating and social behaviors are shaped by culture, so it is critical to examine these associations in different populations. Moreover, FEDs are heterogeneous, and there has been no examination of autistic traits in avoidant/restrictive food intake disorder (ARFID).

METHODS

Therefore, we investigated the prevalence of ASD and autistic traits among Japanese children with AN (n = 92) or ARFID (n = 32) from a prospective multicenter cohort study using the Autism Spectrum Quotient Children's version (AQC) and Children's Eating Attitudes Test (ChEAT26).

RESULTS

ASD prevalence was high in both AN and ARFID (16.3 and 12.5%, respectively). The AN group exhibited significantly higher scores on all AQC subscales than an age-matched healthy control (HC) group, but there were no significant correlations between AQC scores and ChEAT26 scores. In the AFRID group, AQC scores did not differ from HCs, but significant correlations were found between total AQC and ChEAT26 scores and between several AQC and ChEAT26 subscales.

CONCLUSIONS

Both the AN and ARFID groups had high prevalence rates of ASD. The AN group showed a significantly higher degree of autistic traits than the HC group; however, no difference was found between the ARFID and HC groups. Clinicians need to be aware of these rates when working with children with ED.

Eating disturbances in adults with autism spectrum disorder without intellectual disabilities

There is a growing interest in the relationship between autism spectrum disorders (ASDs) and eating disorders (EDs), two relatively common conditions lying on a spectrum from mild to severe clinical features. However, only limited data are available about pathological eating behaviors throughout adults on the autistic spectrum. The aim of the present study is to assess dysfunctional eating behaviors, including EDs manifestations and ASDs-related eating disturbances, in a population of adults with ASDs without intellectual disabilities. We recruited 106 adults on the autistic spectrum, without intellectual disability and 103 neurotypical adults (NAs). Participants completed the "Eating Attitude Test" (EAT-26), to measure symptoms and concerns characteristic of EDs, and the "Swedish Eating Assessment for Autism Spectrum Disorders" (SWEAA), to assess eating behaviors frequently observed within the autistic spectrum. Participants with ASDs scored significantly higher than NA at the EAT-26 and at the SWEAA. Moreover, participants with ASDs scored higher than NA at the EAT-26 subscales Dieting and Bulimia. The difference between groups remained significant after controlling for the effect of age, biological sex, and BMI. These results suggest that adults with ASDs without intellectual disability presented not only a higher prevalence of eating disturbances typical of the autistic spectrum, but also other symptoms of EDs in comparison to NA. LAY SUMMARY: For both scales assessing eating disturbances (EAT-26 and SWEAA), participants with ASDs scored higher than NA, presenting a higher prevalence both of eating disturbances typical of ASDs and of ED symptoms (distorted body image, tendency toward bulimic behaviors, and self-control of eating).

Alexithymia may explain the relationship between autistic traits and eating disorder psychopathology

BACKGROUND

Autistic people are disproportionately vulnerable to anorexia nervosa and other eating disorders (ED), and within the general population, autistic traits correlate with ED psychopathology. A putative mechanism which may underpin this heightened risk is alexithymia, a difficulty identifying and describing emotional states which is observed in both autism and ED. In two experiments with independent non-clinical samples, we explored whether alexithymia might mediate the heightened risk of eating psychopathology in individuals high in autistic traits.

METHODS

Our first experiment used the PROCESS macro for SPSS to examine relationships between alexithymia (measured by the Toronto Alexithymia Scale (TAS-20)), autistic traits (autism quotient (AQ)), and eating psychopathology (Eating Attitudes Test (EAT-26)) in 121 participants. Our second experiment (n = 300) replicated and furthered this analysis by examining moderating effects of sex and controlling for anxiety and depression as covariates. We also included an additional performance-based measure of alexithymia, the Levels of Emotional Awareness Scale (LEAS).

RESULTS

Study 1 suggested that TAS-20 scores mediated the relationship between heightened autistic traits and eating psychopathology. Replication and further scrutiny of this finding, in study 2, revealed that this mediation effect was partial and specific to the female participants in this sample. The mediation effect appeared to be carried by the difficulty identifying feelings subscale of the TAS-20, even when depression and anxiety were controlled for. LEAS scores, however, were not significantly related to autistic traits or eating psychopathology.

LIMITATIONS

Cross-sectional data prevents any conclusions around the direction and causality of relationships between alexithymia, autistic traits, and eating psychopathology (alongside depression and anxiety), necessitating longitudinal research. Our non-clinical sample was predominantly Caucasian undergraduate students, so it remains to be seen if these results would extrapolate to clinical and/or autistic samples. Divergence between the TAS-20 and LEAS raises crucial questions regarding the construct validity of these measures.

CONCLUSIONS

Our findings with respect to autistic traits suggest that alexithymia could partially explain the prevalence of ED in autistic people and may as such be an important consideration in the pathogenesis and treatment of ED in autistic and non-autistic people alike. Further research with clinical samples is critical to explore these ideas. Differences between men and women, furthermore, emphasize the importance of looking for sex-specific as well as generic risk factors in autistic and non-autistic men and women.

Exploring Relationships Between Autism Spectrum Disorder Symptoms and Eating Disorder Symptoms in Adults With Anorexia Nervosa: A Network Approach

Over the past few decades, research has accumulated to suggest a relationship between anorexia nervosa (AN) and autism spectrum disorder (ASD). Elevated ASD traits are present in around one third of those with AN, and there is some evidence to suggest that ASD traits are associated with more severe eating disorder (ED) psychopathology. The current study aimed to examine relationships between ED and ASD symptoms in individuals with a lifetime history of AN using network analysis. One hundred and one participants completed the ED Examination Questionnaire (EDE-Q) and the Social Responsiveness Scale (SRS-2). A regularized partial correlation network was estimated using a graphical least absolute shrinkage and selection operator. Expected influence (EI) and bridge EI values were calculated to identify central and bridge symptoms respectively. Isolation, difficulties with relating to others, and feelings of tension during social situations were most central to the network, while poor self-confidence, concerns over eating around others, and concerns over others seeing one's body were the strongest bridge symptoms. Our findings confirm that interpersonal problems are central to ED psychopathology. They also suggest poor self-confidence and social anxiety-type worries may mediate the relationship between ED and ASD symptoms in those with a lifetime diagnosis of AN. Longitudinal studies examining fluctuations in symptoms over time may be helpful in understanding direction of causality.

Subthreshold autism spectrum disorder in patients with eating disorders

AIM

Increasingly data suggest a possible overlap between psychopathological manifestations of eating disorders (EDs) and autism spectrum disorders (ASD). The aim of the present study was to assess the presence of subthreshold autism spectrum symptoms, by means of a recently validated instrument, in a sample of participants with EDs, particularly comparing participants with or without binge eating behaviours.

METHODS

138 participants meeting DSM-5 criteria for EDs and 160 healthy control participants (HCs), were recruited at 3 Italian University Departments of Psychiatry and assessed by the SCID-5, the Adult Autism Subthreshold Spectrum (AdAS Spectrum) and the Eating Disorders Inventory, version 2 (EDI-2). ED participants included: 46 with restrictive anorexia (AN-R); 24 with binge-purging type of Anorexia Nervosa (AN-BP); 34 with Bulimia Nervosa (BN) and 34 with Binge Eating Disorder (BED). The sample was split in two groups: participants with binge eating behaviours (BEB), in which were included participants with AN-BP, BN and BED, and participants with restrictive behaviours (AN-R).

RESULTS

participants with EDs showed significantly higher AdAS Spectrum total scores than HCs. Moreover, EDs participants showed significantly higher scores on all AdAS Spectrum domains with the exception of Non verbal communication and Hyper-Hypo reactivity to sensory input for AN-BP participants, and Childhood/Adolescence domain for AN-BP and BED participants. Participants with AN-R scored significantly higher than participants with BEB on the AdAS Spectrum total score, and on the Inflexibility and adherence to routine and Restricted interest/rumination AdAS Spectrum domain scores. Significant correlations emerged between the Interpersonal distrust EDI-2 sub-scale and the Non verbal communication and the Restricted interest and rumination AdAS Spectrum domains; as well as between the Social insecurity EDI-2 sub-scale and the Inflexibility and adherence to routine and Restricted interest and rumination domains in participants with EDs.

CONCLUSIONS

Our data corroborate the presence of higher subthreshold autism spectrum symptoms among ED participants with respect to HCs, with particularly higher levels among restrictive participants. Relevant correlations between subthreshold autism spectrum symptoms and EDI-2 Subscale also emerged.

Maternal body mass index before pregnancy as a risk factor for ADHD and autism in children

The risk of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASD) may be influenced by environmental factors such as maternal obesity before pregnancy. Previous studies investigating those associations have found divergent results. We aim to investigate in a large birth cohort this association further in children with ADHD, ASD and comorbid ADHD and ASD. Our study population consisted of 81,892 mother-child pairs participating in the Danish National Birth Cohort (DNBC). Information about pre-pregnancy weight and height was collected in week 16 of pregnancy; the analysis was divided into groups based on BMI. Children with a clinical diagnosis of ADHD and/or ASD were identified in the Danish health registries at an average age of 13.3 years. Hazard ratios (HRs) were estimated using time-to-event analysis. Compared to normal weight mothers, the risk of having a child with ADHD was significantly increased if the mother was overweight (HR = 1.28 [95% CI 1.15;1.48]), obese (HR = 1.47 [95% CI 1.26;1.71]) or severely obese (HR = 1.95 [95% CI 1.58;2.40]). The same pattern was seen for the combined ADHD and ASD group. Regarding ASD, an increased risk was observed in underweight (HR = 1.30 [95% CI 1.01;1.69]) and obese (HR = 1.39 [95% CI 1.11;1.75]) mothers. Subgroup analysis revealed that the association in the ADHD group could mostly be attributable to the hyperactive group. Maternal obesity before pregnancy is a risk factor for ADHD in children. Maternal obesity as well as underweight may also be associated with an increased risk for ASD.

Investigation of Autism Spectrum Disorder and Autistic Traits in an Adolescent Sample with Anorexia Nervosa

This study aimed to examine the presence of Autism Spectrum Disorder (ASD) in a sample of female adolescents with Anorexia Nervosa (AN) during the acute phase of illness. We also compare the level of autistic traits, social perception skills and obsessive-compulsive symptoms in four groups: AN, ASD, and two gender- and age-matched control groups. Of the 30 AN participants, only three scored above the conventional ADOS-2 threshold for ASD. The AN participants were similar to their controls on autistic trait measures, and to the ASD group on obsessive-compulsive measures, and on theory of mind ability and affect recognition measures. Further longitudinal studies are needed in order to determine the association between these conditions.

Embedded Figures Test Performance in the Broader Autism Phenotype: A Meta-analysis

People with autism show superior performance to controls on the Embedded Figures Test (EFT). However, studies examining the relationship between autistic-like traits and EFT performance in neurotypical individuals have yielded inconsistent findings. To examine the inconsistency, a meta-analysis was conducted of studies that (a) compared high and low Autism-Spectrum Quotient (AQ) groups, and (b) treated AQ as a continuous variable. Outcomes are consistent with superior visual search forming part of the broader autism phenotype, but in existing literature, this is evident only when comparing extreme groups. Reanalysis of data from previous studies suggests findings are unlikely to be driven by a small number of high scorers. Monte Carlo simulations are used to illustrate the effect of methodological differences on results.

Adult Autism Subthreshold Spectrum (AdAS Spectrum): Validation of a questionnaire investigating subthreshold autism spectrum

AIM

Increasing literature has shown the usefulness of a dimensional approach to autism. The present study aimed to determine the psychometric properties of the Adult Autism Subthreshold Spectrum (AdAS Spectrum), a new questionnaire specifically tailored to assess subthreshold forms of autism spectrum disorder (ASD) in adulthood.

METHODS

102 adults endorsing at least one DSM-5 symptom criterion for ASD (ASDc), 143 adults diagnosed with a feeding and eating disorder (FED), and 160 subjects with no mental disorders (CTL), were recruited from 7 Italian University Departments of Psychiatry and administered the following: SCID-5, Autism-Spectrum Quotient (AQ), Ritvo Autism and Asperger Diagnostic Scale 14-item version (RAADS-14), and AdAS Spectrum.

RESULTS

The AdAS Spectrum demonstrated excellent internal consistency for the total score (Kuder-Richardson's coefficient=.964) as well as for five out of seven domains (all coefficients>.80) and sound test-retest reliability (ICC=.976). The total and domain AdAS Spectrum scores showed a moderate to strong (>.50) positive correlation with one another and with the AQ and RAADS-14 total scores. ASDc subjects reported significantly higher AdAS Spectrum total scores than both FED (p<.001) and CTL (p<.001), and significantly higher scores on the Childhood/adolescence, Verbal communication, Empathy, Inflexibility and adherence to routine, and Restricted interests and rumination domains (all p<.001) than FED, while on all domains compared to CTL. CTL displayed significantly lower total and domain scores than FED (all p<.001). A significant effect of gender emerged for the Hyper- and hyporeactivity to sensory input domain, with women showing higher scores than men (p=.003). A Diagnosis* Gender interaction was also found for the Verbal communication (p=.019) and Empathy (p=.023) domains. When splitting the ASDc in subjects with one symptom criterion (ASD₁) and those with a ASD, and the FED in subjects with no ASD symptom criteria (FED₀) and those with one ASD symptom criterion (FED₁)_, a gradient of severity in AdAS Spectrum scores from CTL subjects to ASD patients, across FED₀, ASD₁, FED₁ was shown.

CONCLUSIONS

The AdAS Spectrum showed excellent internal consistency and test-retest reliability and strong convergent validity with alternative dimensional measures of ASD. The questionnaire performed differently among the three diagnostic groups and enlightened some significant effects of gender in the expression of autistic traits.

Emotions mediate the relationship between autistic traits and disordered eating: A new autistic-emotional model for eating pathology

The aim of the study was to assess the extent of overlap between autistic traits, body dissatisfaction and disordered eating and to explore the mediating effects of negative attitudes towards emotional expression and emotion dysregulation. The sample comprised 416 university students (82% females, 17-48 years [M=19.76, SD=3.85]), who completed an online questionnaire assessing eating attitudes and behaviours (including dieting, bulimia and oral control), body dissatisfaction, and autistic traits (including the Autism Quotient [AQ] and its related subscales as well as the Empathising Quotient). Attitudes towards emotional expression and emotion regulation were also assessed. Results revealed that eating pathology correlated highly with all AQ subscales, with the exception of the attention to detail subscale. However, there was no significant relationship between empathising and eating pathology. Path-analyses indicated that emotion dysregulation, but not negative attitudes towards emotional expression, was a significant mediator of the relationship between AQ, body dissatisfaction and eating pathology. Direct relationships were also obtained for the AQ-bulimia and the AQ-oral control paths. Prevention and early intervention programs for eating pathology would likely benefit from addressing abnormalities in emotion processes in individuals who score highly on measures of autistic traits.