Anorexia Nervosa and Autism Spectrum Disorder: Is There an Association?

Background: Recent studies have reported a high level of autistic traits in population with anorexia nervosa (AN). Moreover, a number of cognitive features associated with Autism Spectrum Disorder (ASD) has been described in AN samples. However, it is unclear to what extent these are manifestations of ASD or whether they are the manifestations of the starvation phase of the illness. To date, few studies have used contemporary methods to confirm the diagnosis of ASD.

Objectives: The aim of the present study was to examine the presence of ASD in a group of AN during the starvation phase using the gold-standard diagnostic measure for autism (i.e., ADOS-2). We also compared the level of autistic traits and the performance on a common social perception task across four groups: AN, ASD, and two gender- and age-matched control groups (C-AN, C-ASD).   

Methods: 30 female AN participants in the acute phase of illness, 27 male ASD participants and two healthy, age and gender-matched controls groups (n=35 females; n=30 males) were enrolled in this study. Controls were screened for AN with the Eating Attitude Test-26 and the Eating Disorder Invenory-3. The ADOS-2 Module 3 was administered by a psychologist trained to research reliability to the AN and the ASD groups. Parents of all individuals completed the Autism Spectrum Quotient (AQ). Subjects completed the NEPSY-II social perception domain (i.e., Theory of mind-TOM and Affect Recognition-AR).

Results: Of the 30 AN participants evaluated using the ADOS-2, 1 was classified on the ADOS algorithm as having autism (Social Affect-SA=9, Restricted/Repetitive Behaviors or Interests-RRB=0, Overall Total-OT= 9); two scored in the ASD range (SA=7, RRB=0, OT=7 both participants)(Figure 1). The remaining participants scored below the ADOS threshold for ASD. Moreover, no similarity between the AN and the ASD groups were detected on the AQ (total and sub-scores) (AN: AQ Total: 18.17 ± 5.92, ASD:AQ Total: 29.6± 6.45, t=5,272, p<0.001) and the NEPSY-II domain. On the other hand, the ASD group had higher scores only on the AQ social skill subscale compared to the C-ASD group (t=3,927, p<0.001). Whereas the C-AN scored higher on the AQ attention to detail (t=-2,082, p=.043), communication (t=-1,138, p=.022) and imagination (t=-1,155, p=.020) subscales and on the NEPSY TOM domain (t=-,813, p=.012) compared to the AN group.

Conclusions: To our knowledge, this is the first study evaluating an AN sample during the starvation phase using the ADOS. Only 10% of subjects in the AN group scored above the conventional ADOS threshold. In these three AN subjects, none was rated above threshold for RRB. On the AQ, none of the AN subjects exceeded the threshold, suggesting low level of autistic traits. On the social perception domain tasks, the ASD group showed significantly greater impairment than the AN group. Our findings do not support the presence of autistic traits in individuals with AN. Further longitudinal studies are needed in order to determine the association between these conditions.