The impact of alexithymia on autism diagnostic assessments

Abstract

Alexithymia, a difficulty identifying and communicating one’s own emotions, affects socio-emotional processes, such as emotion recognition and empathy. Co-occurring alexithymia is prevalent in Autism Spectrum Disorder (ASD) and underlies some socio-emotional difficulties previously attributed to autism. Socio-emotional abilities are examined during behavioural diagnostic assessments of autism, yet the effect of alexithymia on these assessments is not known. In this study, two previously collected samples of Autism Diagnostic Observation Schedule (ADOS) assessments were used to examine the relationship between alexithymia and ADOS score. Participants included 96 women with anorexia, and 147 adolescents who were either high in autistic symptoms, or whose twin had high autistic symptoms. We examined 1) the impact of alexithymia on meeting the criteria for autism/ASD, 2) correlations between alexithymia and ADOS subscales, and 3) whether alexithymia predicted scores on specific ADOS items, selected a priori based on the literature. In the adolescent group, parent-reported (but not self-reported) alexithymia predicted autism/ASD diagnosis, correlated with both sub-scales, and predicted scores on ADOS items. Fewer associations were observed in the anorexic sample, but the presence of alexithymia predicted a near fourfold increase in the likelihood of meeting diagnostic criteria for autism/ASD in this sample.

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

“…Casting doubt on previous evidence of a direct relationship between autistic traits and eating psychopathology, our data is redolent of the recent findings from Hobson et al [92]. These authors found that anorexic patients were more likely to reach diagnostic cut-offs for autism if they also exhibited comorbid alexithymia (measured in TAS-20 scores).…”

“…Firstly, our cross-sectional design, though convenient for testing these initial hypotheses, disallows more rigorous scrutiny of causality and direction of these relationships. We cannot dismiss the alternative interpretation, for instance, that degree of alexithymia in our samples inflated the appearance of autistic traits (as might be supported by Hobson and colleagues [92]) and that autistic traits themselves predispose for eating difficulties. Neither can we dismiss the possible causal primacy of eating disordered behaviours giving rise to alexithymia (which, from then, might inflate autistic traits).…”

“…In a similar vein to studies disentangling the features of anorexia and autism from those of alexithymia, we query whether the relationship between the two, likewise, is in part a product of this comorbid condition. This has been precisely implied in recent, unpublished research with autistic individuals and a clinical anorexic sample, where Hobson and colleagues observed that alexithymia increased the chances of both groups meeting cut-off criteria for autism diagnosis [92]. In increasing the likelihood that anorexic individuals were more likely to meet ASC criteria on ADOS-2 items related to social affect and social insight, the authors suggest that "co-occurring alexithymia may be a potential explanation for the high proportion of patients with AN who exhibit symptoms of ASD" (p. 22).…”

“…Furthermore, whilst investigation at trait or subclinical level within the general population is useful for hypothesis testing, the findings of the present study cannot be presumed generalizable to clinical populations: in this case, individuals with diagnosed autism and eating disorders. In populations with ED, previous research has established that alexithymia (high TAS-20 scores) increases the likelihood of an autism diagnosis [92]. Therefore, it would be necessary to examine whether heightened autistic traits, as commonly found with the AQ [43], are maintained when alexithymia is controlled for.…”

How Closely Related Are Parent and Child Reports of Child Alexithymia?

“…Thus, parents higher in alexithymia might have more difficulty reporting on their child’s level of alexithymia. Because previous work has found a relation between alexithymia and autism symptomatology in adults (e.g., Berthoz et al, 2013 ; Aaron et al, 2015 ; Gökçen et al, 2016 ; but also see Hobson et al, 2018 ), we also considered the possibility that parents higher in autism symptomatology would have more difficulty reporting on their child’s level of alexithymia. We found no relation between parent levels of alexithymia and autism symptomatology and neither predicted parent report of child alexithymia, though these analyses were also underpowered.…”