Saturday, 27 August 2016

On autism spectrum disorder [research] validity

Today I'm directing your reading attention to a really, really interesting paper by Lynn Waterhouse and colleagues [1] (open-access) whose review findings suggest that: "the ASD [autism spectrum disorder] diagnosis lacks biological and construct validity."

The paper is a bit of a long read but most definitely worth it as the quite complicated subject of exactly what goal the label of autism actually serves is discussed. The results of various questions posed by the authors suggest: "No unitary ASD brain impairment or replicated unitary model of ASD brain impairment exists. ASD core diagnostic symptoms are not uniquely linked and are only very rarely expressed without nondiagnostic symptoms. ASD has no reliable early predictor, no unitary developmental course, no unitary life outcome, no unitary recurrence risk, no unitary pattern of BAP [broader autism phenotype] features, and no standard homogeneous subgroups." They conclude that from a research perspective at least, disbanding the label of autism as it currently stands is the next logical step. Said disbanding "is likely to be reductive and uncomfortable" particularly when it comes to all those grand [sweeping] theories of autism put forward down the years. Feathers would not doubt be ruffled.

The authors do make reference to two important concepts when it comes how we might want to rethink autism: the Research Domain Criteria framework (RDoC) and Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations (ESSENCE). One is an attempt to move away from simple psychiatric labels as somehow denoting homogeneity, the other is the recognition that labels rarely appear in some sort of diagnostic vacuum. Both are in some way the future of autism research and indeed, the future is already now.

I'm impressed with the paper from Waterhouse et al. The authors have done a good job of basically saying that as things stand, one single label covering such a diverse and heterogeneous group is not fit for purpose. To see real progress in autism research, science needs to think more about those 'autisms' (see here) and stop using the label of autism as the starting point for research (see here). I struggle to disagree with both those sentiments and other authors appear to have reached similar conclusions [2]. Exactly what that means for the autism in the future - from both a research and clinical perspective - is still a little up in the air but the label has weathered change before and no doubt will continue to do so.

And if that isn't enough reading material for you, how about the latest instalment from the British Psychological Society here in Blighty when it comes to autism? Perhaps this will need a revision or two as the Waterhouse suggestions start to percolate through the research community?

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[1] Waterhouse L. et al. ASD validity. Review Journal of Autism and Developmental Disorders. 2016. Aug 10.

[2] Geier DA. et al. Examining genotypic variation in autism spectrum disorder and its relationship to parental age and phenotype. Appl Clin Genet. 2016 Jul 28;9:121-9.

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ResearchBlogging.org Waterhouse, L., London, E., & Gillberg, C. (2016). ASD Validity Review Journal of Autism and Developmental Disorders DOI: 10.1007/s40489-016-0085-x