"anxiety occurring as a consequence of ASD symptoms"

Although not necessarily a popular idea, I have for a while been coming around to the possibility that various 'comorbidities' associated with a diagnosis of autism or autism spectrum disorder (ASD) represent more than just 'comorbidity'. I'm not specifically talking about medical comorbidity such as epilepsy or seizure disorder being intricately related to autism (although there is evidence for such a relationship) but rather that co-occurring clinical and sub-clinical psychiatric issues such as depression and anxiety potentially 'come about' partially as a result of the presence of autistic traits and characteristics (see here and see here).

As I said, this is not a universally popular idea. In the age of the emergence of an 'autistic identity' and an increasingly vocal group of people wanting to discuss what role societal factors play with regards to quality of life in the context of autism (see here), the idea that autistic traits themselves might in some way predispose for various other, often very disabling conditions, is not easy to reconcile. Even more so if the implication for managing things like anxiety and/or depression might mean 'targeting' core autistic features for intervention...

The findings such as those reported by Elizabeth Shephard and colleagues [1] "testing the specificity of early-life (infant and toddler) predictors of mid-childhood ADHD [attention-deficit hyperactivity disorder] and anxiety symptoms compared to ASD symptoms" provide however, another tier of evidence that (a) autism rarely exists in some sort of diagnostic vacuum (see here), and (b) something like the symptoms of anxiety appearing alongside autism could "reflect the presence of common developmental pathways or convergence in early behavioural manifestations."

Shephard et al discuss results obtained from the British Autism Study of Infant Siblings (BASIS) initiative, a collaboration based here in Blighty aiming to "provide a platform for the study of infants at-risk for autism in the UK and to facilitate collaborative links between scientists working in the area." High-risk (i.e. having a sibling diagnosed with ASD) and low-risk infants were followed and tested for various symptoms and traits covering autism and also ADHD and anxiety at various points during their childhood development: "7, 14, 24 and 38 months, and 7 years of age." Importantly, because measuring things like anxiety in young children is still quite a challenge, researchers used other soft signs and symptoms - fearfulness and shyness - as "early-life predictors of anxiety symptoms." Some nifty statistical methods were applied to the collected data.

Results: "Increased activity levels and poor inhibitory control were correlated with ADHD symptoms and not ASD or anxiety; these associations were unchanged in path models controlling for risk-group and ASD symptoms." The authors interpreted these findings as evidence that "these disorders may have distinct developmental origins and are therefore unlikely to reflect a common condition" with a specific focus on autism and ADHD. Ergo, when one sees the data pointing to a rather large over-representation of ADHD in the context of autism (see here), this does not necessarily translate into autism being ADHD or vice-verse or them sharing a common developmental pathway.

Additionally: "early‐life markers of anxiety (without ASD) were associated with later anxiety..., but were also associated with later ASD symptoms." When looking at those early-life markers of [possible] anxiety, and how they *linked* to the symptoms of autism, authors highlighted how "these disorders are difficult to differentiate early in life, which could reflect the presence of common developmental pathways or convergence in early behavioural manifestations of these disorders." In other words, there may be some intricate links between them.

Of course, lots more research is needed in this area, as authors mention about the use of "parent‐rated measures of early‐life predictors and mid‐childhood symptoms of ADHD, anxiety and ASD" and what that could mean for the quality of the information obtained. Personally, I'd be inclined to suggest that parents are often 'under-rated' in their contributions to autism research (see here for example) including on the specific issue of anxiety and autism (see here). But I guess every study can be improved in some respect.

What's more to say on this topic? Well, I'm minded to bring in some other, rather 'left-field' evidence for how autism and anxiety might be more intricately linked than hitherto suggested, in the form of some work looking at selective mutism and autism (see here). How, a condition centrally identifying with anxiety (selective mutism), also seemingly heightens the risk of autism being subsequently diagnosed well beyond what would be expected. I don't doubt that there other examples of anxiety-related conditions also potentially increasing the likelihood of autism presenting clinically further strengthening the 'beyond just comorbidity' sentiments.

And set within this emerging research/clinical picture [2], we then go back to the idea that some autistic traits might be 'promoters' of something like anxiety in the context of autism, and back to the important question of what to do about them...

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[1] Shephard E. et al. Early developmental pathways to childhood symptoms of attention-deficit hyperactivity disorder, anxiety and autism spectrum disorder. J Child Psychol Psychiatry. 2018 Jul 2.

[2] Spain D. et al. Social anxiety in autism spectrum disorder: A systematic review. Research in Autism Spectrum Disorders. 2018; 52: 51-68.

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Selective mutism and autism

The findings reported by Hanna Steffenburg and colleagues [1] make for potentially important reading reporting: "In this study of a clinical group of children who were diagnosed with SM [selective mutism] and assessed at a center for neurodevelopmental disorders, 63% also met criteria for ASD [autism spectrum disorder]."

Selective mutism (SM) refers to an anxiety disorder typically manifesting during early childhood that affects the use of spoken language in certain social situations such as at school. 'Literally being unable to speak' is a phrase that follows SM in certain contexts, where speech and language skills are not typically affected when and where family or close friends are around. It's not surprising that there is 'overlap' between SM and autism given the characterisation of SM in terms of being "nervous, uneasy or socially awkward" and "stiff, tense or poorly co-ordinated" (minus any sweeping generalisations). And just before you question it, 'poorly-coordinated' is perhaps an under-rated aspect for many people diagnosed as being on the autism spectrum (see here).

Steffenburg and colleagues - including the notable ESSENCE-related name of Christopher Gillberg - sought to examine the possible 'overlap' of SM and autism on the basis that various diagnoses/labels can occur alongside SM; quite a few of them also recognised in relation to autism (see here). Approaching 100 children/young adults diagnosed with selective mutism were assessed at the premier 'autism spectrum conditions' clinic in Gothenberg, Sweden. The clinical assessment undertaken of course covered the diagnosis of autism but also various cognitive functions too.

Almost two-thirds of those with SM who were assessed also met criteria for an autism spectrum disorder (ASD). Added to that: "A further 20% (n=19) had autistic features that were “subclinical”, but, nevertheless, sufficiently marked to have an impact on everyday life." Only 17% were described as having no ASD symptoms. Those are pretty interesting percentages.

Authors also mention how: "The level of cognitive function was average in more than half of the study group but more than one-third of the study group had a borderline IQ or an ID [intellectual disability]." They use such a finding in the context of the ESSENCE term - Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations - where overlapping diagnoses/labels is the rule not the exception.

The implications? Well, screen and keep a continual eye open for autism in cases of SM seems to be an important first implication. That also includes keeping in mind those 'subclinical' signs and symptoms, which could be relevant to discussions about the broader autism phenotype (BAP) (see here) and also that curious DSM-5 diagnostic category known as social communication disorder (SCD) (see here). The focus on 'anxiety' in relation to SM might also be important given the pretty well-established connection between autism and anxiety (see here for example) following in the footsteps of some often forgotten autism research history (take a bow Mildred Creak and colleagues for including the term "acute, excessive and seemingly illogical anxiety"). I'm also minded to mention that given the pretty high rate of autism described in SM by Steffenburg and other researchers, further investigations perhaps need to be directed towards shared biology/genetics as well as shared behavioural presentation? Y'know, along the lines of whether 'comorbidity' might be something more 'core' (see here)?

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[1] Steffenburg H. et al. Children with autism spectrum disorders and selective mutism. Neuropsychiatr Dis Treat. 2018 May 7;14:1163-1169.

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