Abstract
Background:
Although research suggests a relationship between restrictive eating disorders (EDs) and autism, there is a lack of research in this area from the perspective of autistic men. Our aim was to explore whether ED symptoms are heightened in autistic men compared with nonautistic men.
Methods:
We recruited 103 autistic and nonautistic participants through an online study. We assessed ED symptoms, autistic features, anxiety, depression, and body mass index (BMI) using self-report measures.
Results:
Autistic men (n = 54) exhibited significantly higher levels of ED symptoms in the areas of eating (p < 0.001), shape (p = 0.005), and weight (p = 0.001) concerns, and the global score (p = 0.046) than nonautistic men (n = 49). However, autistic men scored significantly lower in the area of dietary restraint (p = 0.032). Global ED scores did not correlate with autistic traits, but did correlate with anxiety (p < 0.001) and BMI (p < 0.001) in the autistic group.
Conclusions:
This exploratory study suggests that heightened ED symptoms in autistic men may be related to heightened levels of anxiety and higher BMIs, rather than autistic traits. It also highlights that autistic men may experience symptoms not relating to dietary restraint. Future research should consider further exploring the relationship between anxiety, BMI, and disordered eating in autism.
Lay Summary
Why was this study done?
There is a lot of interest in the relationship between autism and eating disorders (EDs). Research suggests that as many as one in four people with anorexia could be autistic. However, most research has been done (1) on women and (2) looking at autistic traits in women with anorexia. There is less research looking at the relationship from the perspective (1) of men and (2) looking at ED symptoms in autistic people.
What was the purpose of this study?
We aimed to explore whether autistic men experience more ED symptoms than nonautistic men.
What did the researchers do?
This was an online study. We asked participants to fill out self-report measures of autistic traits and ED symptoms. We also asked participants to self-report whether they were autistic, and whether they had been previously diagnosed with an ED. We included 54 autistic men and 49 nonautistic men.
What were the results of the study?
We found that although autistic men did experience higher levels of ED symptoms than nonautistic men, this did not appear to be related to autistic traits. Instead ED symptoms were related to anxiety and higher rates of being overweight or obese. In addition, autistic men in fact experienced significantly lower levels of ED symptoms associated with dietary restraint than nonautistic men.
What do these findings add to what was already known?
Our findings reflect some previous research findings that ED symptoms may be heightened in autistic people. They also suggest that these symptoms are related to higher levels of anxiety or body mass indexes (BMIs) in autistic people, rather than autistic traits themselves. Also, most previous research has focused on symptoms of restraint in EDs and autism, for example, limiting the amount you eat or not eating certain foods. In our study, restraint was not found to be heightened, suggesting that focusing on restraint symptoms might be less relevant to autistic men.
What are potential weaknesses in the study?
One key weakness is our use of self-report measures, particularly asking participants to self-report their autism diagnosis. An additional limitation is the small sample size, which makes it hard to generalize findings.
How will these findings help autistic adults now or in the future?
More research is needed to understand the relationship between anxiety, BMI, autism, and ED symptoms. Our findings could help our understanding of disordered eating in autistic adults as they suggest we need to pay more attention to autistic adults experiencing ED symptoms that are not related to dietary restriction, such as binge eating.
Keywords: autism, eating disorders, co-occurring conditions, men, adults
Introd2uction
The relationship between autism and eating problems in children is well established.1,2 There is comparatively less research in adults, although there is a growing interest in the relationship between autism and eating disorders (EDs). Research suggests that women with anorexia nervosa (AN) exhibit higher rates of autistic traits than the general population, with around one in four women with AN qualifying for a diagnosis.3–5 However, less research has examined the relationship between autism and EDs from the opposite perspective: exploring the presence of ED symptoms in autistic adults.
A recent study found that ED symptomatology appeared to be heightened in autistic individuals.6 Of the participants in the sample reporting a current or previous ED, the male–female ratio was 1:2.5. In the general population, men are thought to represent around one in four to one in five people with EDs, suggesting that the gender ratio of EDs in autistic populations may be less skewed.7,8 Nonetheless, previous research on autism in EDs has been carried out almost exclusively on women only, whereas autism predominantly affects men.9 Therefore, the aim of our study was to explore whether ED symptoms are heightened in autistic men than in nonautistic men.
Methods
Procedure
We invited autistic and nonautistic people aged 18 years and above in the community to take part in an online study titled “Problematic Eating on the Autism Spectrum.” We recruited participants online through Twitter inviting participants to complete questionnaires on a survey website. Participants from any country were able to participate; however, they needed to be able to read and write sufficient English to complete the questionnaires. Ethical approval was received from King's College London Psychiatry, Nursing and Midwifery Research Ethics Panel, reference LRS-17/18-5292.
Participants
Participants were included in this analysis if they self-identified in the study as men. A total of 124 individuals (56 nonautistic men and 68 autistic men) completed the questionnaires. We identified participants as autistic in this study if they self-reported being on the autism spectrum, and the Autism Spectrum Quotient (AQ)-Short suggested heightened levels of autistic traits. Some men reported a formal diagnosis of autism, whereas others reported self-diagnosis. Self-diagnosed men were included in this study as some individuals experience barriers to formal diagnosis, and these participants scored above threshold on the AQ-Short.10 We identified participants as nonautistic if they reported having never been diagnosed as autistic, and if they scored below the cutoff indicative of heightened levels of autistic traits on the AQ-Short. Participants not meeting these group criteria were excluded, leaving a sample of 54 autistic men and 49 nonautistic men.
Measures
Participants self-reported demographic data and ED history. Participants were asked whether they were currently experiencing an ED, whether they had previously experienced an ED, and to provide information on illness duration. We calculated body mass index (BMI) from self-reported weight and height: an underweight BMI was defined as <18.5 kg/m2, an overweight BMI defined as ≥25 kg/m2, and an obese BMI defined as ≥30 kg/m2.
Eating Disorder Examination Questionnaire
The Eating Disorder Examination Questionnaire (EDE-Q) is a self-report measure of ED behaviors assessing the presence of disordered eating attitudes and behaviors for the past 28 days.11 This provides four subscale scores: Restraint, Eating Concern, Shape Concern, and Weight Concern, as well as a global summary score. A higher score indicates higher levels of ED pathology. In line with previous research in this area, a cutoff of ≥4 for each subscale was used as a marker of clinical significance.12 The EDE-Q has not previously been used in autistic populations.
AQ-Short
The AQ-Short is an abridged 28-item version of the AQ, a self-report measure of autistic traits in adults.13 The scale contains 28 descriptive statements, to which participants respond on a Likert scale. A higher score indicates higher levels of autistic traits, with a cutoff score of >65 potentially indicating autism.
Hospital Anxiety and Depression Scale
The Hospital Anxiety and Depression Scale (HADS) is a 14 item self-report scale designed to assess the presence of anxiety and depression in adults.14 Participants respond to descriptive statements on a Likert scale, with a higher score indicating higher levels of anxiety or depression. The HADS has previously been validated in autistic populations.15
Data analysis
We made statistical comparisons in Stata (Version 15) using nonparametric tests after Shapiro–Wilk tests indicated non-normal distribution. We calculated group differences using Mann–Whitney U tests. Owing to small cell sizes, Fisher's exact test was used to compare categorical group differences. We calculated Spearman's Rho coefficients to explore associations between EDE-Q global summary scores and autistic traits, anxiety, depression, and BMI for the autistic group.
Results
Participant characteristics are summarized in Table 1. Autistic participants were significantly older than the nonautistic group and reported significantly higher BMIs. Autistic men scored significantly higher on the AQ-Short, on the HADS anxiety scale, and on the HADS depression scale. There were no significant differences in race/ethnicity across groups, although 29.63% of autistic men did not respond to this question without giving a reason.
Table 1.
Participant Characteristics Across Groups
| Nonautistic M (SD) | Autistic M (SD) | Test statistic | p-Value | |
|---|---|---|---|---|
| Age | 32.81 (1.61)a | 38.80 (1.83)a | U = 986.5a | 0.027a |
| BMI | 24.44 (0.48)b | 27.77 (0.79)b | U = 817.5b | 0.001b |
| AQ-Short score | 9.49 (0.61)b | 22.41 (0.30)b | U = 0b | <0.001b |
| HADS anxiety | 6.88 (0.58)b | 12.28 (0.66)b | U = 529.5b | <0.001b |
| HADS depression | 4.43 (0.44)b | 8.76 (0.59)b | U = 530b | <0.001b |
| Race/ethnicity, n (%) | 0.202 | |||
| White | 39 (79.59%) | 35 (64.81%) | ||
| Asian | 4 (8.16%) | 0 (0%) | ||
| Black | 0 (0%) | 0 (0%) | ||
| Latinx | 1 (2.04%) | 2 (3.70%) | ||
| Mixed | 3 (6.12%) | 1 (1.85%) | ||
| No response | 2 (4.08%) | 16 (29.63%) |
p < 0.05.
p < 0.01.
AQ, Autism Spectrum Quotient; BMI, body mass index; HADS, Hospital Anxiety and Depression Scale.
No nonautistic man reported being currently diagnosed with an ED, but two did report having previously recovered. One autistic man reported having a current ED diagnosis, and six reported having recovered. However, autistic men were not significantly more likely to have any lifetime experience of an ED.
Group differences in ED symptomatology are summarized in Table 2. Autistic participants reported significantly higher mean scores on eating, shape and weight concern subscales, and the global score than nonautistic men. However, autistic participants reported significantly lower mean scores on the Restraint subscale. Although more autistic participants scored above the threshold for clinical significance on all subscales compared with nonautistic men apart from the Restraint subscale, differences were only significant on the Weight Concern subscale. Autistic men were not significantly more likely to regularly engage in eating disordered behaviors.
Table 2.
Group Differences on the Eating Disorder Examination Questionnaire
| |
Nonautistic |
Autistic |
|
|
|---|---|---|---|---|
| Subscale scores | M (SD) | M (SD) | Test statistic | p-Value |
| Restraint | 1.73 (0.21)a | 1.2 (0.21)a | U = 1004a | 0.032a |
| Eating concern | 0.49 (0.12)b | 1.13 (0.17)b | U = 801.5b | <0.001b |
| Shape concern | 1.54 (0.18)b | 2.52 (0.24)b | U = 888.5b | 0.005b |
| Weight concern | 1.22 (0.17)b | 2.28 (0.23)b | U = 829b | 0.001b |
| Global | 1.25 (0.14)a | 1.78 (0.18)a | U = 1021a | 0.046a |
| Number scoring above subscale thresholds (≥4) | n (%) | n (%) | p-Value (Fisher's exact test) | |
|---|---|---|---|---|
| Restraint |
3 (6.12) |
3 (5.56) |
— |
1.00 |
| Eating concern |
1 (2.04) |
2 (3.70) |
— |
1.00 |
| Shape concern |
2 (4.08) |
9 (16.67) |
— |
0.055 |
| Weight concern |
3 (6.12)a |
11 (20.37)a |
— |
0.045a |
| Global | 1 (2.04) | 4 (7.14) | — | 0.366 |
| Number endorsing specific behavioral items | n (%) | n (%) | p-Value (Fisher's exact test) | |
|---|---|---|---|---|
| Excessive exercise |
1 (2.04) |
0 (0.00) |
— |
0.48 |
| Dietary restraint |
0 (0.00) |
0 (0.00) |
— |
— |
| Binge episodes |
9 (18.37) |
17 (31.48) |
— |
0.173 |
| Self-induced vomiting |
0 (0.00) |
0 (0.00) |
— |
— |
| Laxative misuse | 0 (0.00) | 1 (21.85) | — | 1.00 |
p < 0.05.
p < 0.01.
There was no significant correlation between the EDE-Q global score and the AQ-Short total score, or the HADS depression score in the autistic group. There was a significant positive correlation between the EDE-Q global score and the HADS anxiety score (r = 0.44, p < 0.001) and BMI (r = 0.40, p = 0.047).
The direction of these findings was not found to significantly differ when only autistic men who self-reported a formal diagnosis of autism, rather than self-diagnosis, were included in the analysis.
Discussion
The aim of this study was to explore self-reported ED symptoms in autistic men. Autistic men scored significantly higher in the areas of eating, shape and weight concern, and the global summary score, as measured by the EDE-Q compared with nonautistic men. However, they scored significantly lower in the area of dietary restraint. Correlational analyses suggest that these heightened symptoms may be related to the heightened levels of anxiety in this population, and higher BMIs, rather than the degree of autistic traits.
That anxiety, and not autism, was found to relate to ED symptoms in autistic men is potentially positive for the prognosis for autistic men experiencing ED behaviors: although autism is a lifelong condition, anxiety can be treated with interventions specifically tailored to autistic individuals.16 This suggests that co-occurring ED behaviors may potentially improve with a reduction in anxiety. Approximately 50% of autistic adults experience an anxiety disorder at some point in their lifetime, and anxiety is also known to be heightened in AN.17–20 With this study supporting a potential relationship between autism, anxiety, and ED symptoms, future research should explore whether anxiety in autism could potentially act as a risk factor for the future development of an ED or as a shared mechanism: a recent systematic review indicates that the high prevalence of social anxiety seen in AN could also be linked to heightened autistic traits in this population.21
BMI was also found to correlate with higher global scores on the EDE-Q in autistic men. In nonautistic populations, heightened EDE-Q scores are similarly associated with higher BMIs.22 This may be particularly relevant for autistic people as previous literature suggests that autistic people are more likely to have a BMI defined as overweight or obese. This has led to suggestions that autism may be associated with eating behaviors relating to excessive energy intake.6,23–26 At present autism has been most explored in the ED literature from the perspective of co-occurring AN in women, an ED associated with low weight and dietary restriction. However, the finding that autistic men in fact scored significantly lower than nonautistic men on measures of dietary restraint suggests a need for research on nonrestrictive disordered eating behaviors in autism.
This report was intended as an exploratory study in the context of a lack of prior research in this area. Consequently, there are a number of limitations, including the reliance on self-report for the presence and validation of an autism diagnosis, demographic data (including height and weight), and ED history and symptomatology. In particular, the EDE-Q has not previously been used in autistic populations, and further examination of this measure in this community is required. In addition, the fact that the study was advertised as exploring “problematic eating” may have introduced selection bias by encouraging people experiencing eating problems to take part. Further research should consider exploring the issues raised in this report in the context of a more controlled study, including more accurate assessments of autism status, and a larger sample size.
Conclusions
Autistic men appear to experience elevated levels of ED symptomatology. However, this is not in the areas of dietary restraint highlighted by previous research into AN and autism.27 The elevated ED behaviors found in this sample may be related to the heightened levels of anxiety and higher BMIs seen in the autistic group, rather than autistic traits.
Author Confirmation Statement
E.K. and F.S. designed the study, supervised by C.S. and K.T. F.S. oversaw data collection. E.K. carried out the analysis. All authors contributed toward the drafting of the article. All coauthors have reviewed and approved of the article before submission. The article has been submitted solely to this journal and is not published, in press, or submitted elsewhere.
Author Disclosure Statement
No competing financial interests exist.
Funding Information
This study was supported by a Medical Research Council Doctoral Training Partnership PhD Studentship (Grant No. MR/N013700/1), the Medical Research Council and Medical Research Foundation Child and Young Adult Mental Health grant (the underpinning etiology of self-harm and EDs), and the Health Foundation, an independent charity committed to bringing better health care for people in the United Kingdom.
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