the article posted by Joost Wiskerke and colleagues  suggesting that "camouflaging of RMs [repetitive movements] may contribute to under diagnosis of autism, at least in females and transgender people" is just a preprint ("a version of a scholarly or scientific paper that precedes publication in a peer-reviewed scholarly or scientific journal"). It has not been through formal peer-review yet, but rather the authors have bravely 'put it out there' for old farts like me to pore over.
Having glanced through the abstract first and discovered the use of the words "self-identified as autistic" my brow furrowed somewhat. Upon further reading of the paper in its entirety, the furrowing brow furrowed a little less as I understood why the authors mentioned use of a cohort that was "56% formally diagnosed participants and 44% who self-identified as autistic." But that's not to say that I was completely enamoured with the study write-up as it currently stands...
Before continuing and in order to repel any accusations that come my way, I'll mention that I don't have any particular issue with people without a formal diagnosis of autism thinking/believing they are on the autism spectrum. It's their right to do so and indeed, such self-realisation is often an important step towards getting a professional assessment for autism. For some people, their hunch about being autistic eventually turns out to be correct as per them reaching defined clinical cut-off points for autism on the various instruments of assessment that are available during said professional assessment. But that's not to say that every person who self-identifies as being autistic/having autism is always going to be right. As we are starting to realise from the wealth of peer-reviewed science on this topic, the label autism does not seemingly have any exclusive rights to the presentation of autistic traits (see here and see here for examples). And it is for that reason why we have so many good and knowledgeable diagnosticians when it comes to such professional assessments, combined with an important focus on: "Symptoms caus[ing] clinically significant impairment in social, occupational, or other important areas of current functioning" in order to receive a diagnosis. Access to such autism assessments is another issue, but shouldn't be used as an excuse...
Wiskerke et al started from the premise that repetitive movements (RMs) are common in autism but there are some potentially important differences in the expression of such issues between the genders. This follows other independent findings in this area (see here) detailing how stereotyped and repetitive behaviours may be less frequently observed in females  minus any sweeping generalisations. Researchers then moved on to suggesting that one of the reasons why such RMs may be less frequently observed is because they are actively being masked or camouflaged, and this could eventually lead to an under-diagnosis of autism among certain groups. 'Masking' or camouflaging in the context of autism is a bit of a hot [social media] topic at the moment (see here and see here).
"In this exploratory study, we took a first step... by using self-report measures from a large number of female and transgender adults, using recruitment on social media to an on line questionnaire." Ah yes, the on line questionnaire, which seems to becoming more and more popular in certain autism research circles  (see here also for another example). There's nothing wrong with using such tools for asking about opinions and the like, but they are typically open to anyone and everyone (who has access to the internet!), and not exactly great for authenticating complicated things like clinical diagnoses, behaviours and comorbidity for example. As for the incorporation of data from transgender adults, well, again this follows a theme in autism research recently (see here) where 'autistic identity' and sexual identity seem to be converging for some people/groups (see here).
"We assessed current RMs using a combination of visual analog scales for specific behaviors and textboxes for free-text responses." There's mention of using some of the DSM-5 criteria for autism in this section. Authors also talk about testing for camouflaging "using the matrix multiple-choice question “Did/do you hide these behaviors from others…” 1) “…as a child?”, 2) “…as an adolescent?”, 3) “…as an adult?”" Yet again (see here) a research priority needs to be the formulation of a valid and reliable questionnaire pertinent to 'measuring' masking/camouflaging with autism in mind. And finally there was the use of an old favourite - the autism spectrum quotient (AQ) - by the authors, but with some added caveats...
Results: "We found high rates of RMs in both diagnosed and self-identifying participants, and a striking prevalence of camouflaging" was one of the headlines. But... there were also some other important details observed too. So: "Higher scores in the diagnosed group were found for object fidgeting, repetitive hand movements, rocking, object spinning and hand flapping." I think most people would agree that such behaviours represent some of the more 'classical' manifestations included in the RM categorisation of autism. By contrast, other RMs such as scratching/rubbing skin, walking in circles and 'banging head' were not different between the diagnosed and self-identifying groups.
Based also on the strength of the camouflaging data presented by Wiskerke et al I have to say that I'm not yet altogether convinced by the evidence presented. It's not that I don't believe that 'self-inhibition' plays a role in such masking, nor that: "There were many references (47 participants) to having been bullied or disciplined for childhood RMs." It's just that methodologically speaking, offering up one question on such a complicated issue does not make for a scientifically compelling argument. As I previously said, autism science needs to invest in some high quality research on how to assess masking in the context of autism; perhaps including some important measure of self-monitoring for example. And one also needs to control for things like intellectual ability too and perhaps be open to other reasons why the presentation of autism between the genders/sexes might be subtly different.
I was also a little dismayed that the discussion of results by the authors did not seem to fully 'tally' with their findings. So: "The striking similarities between diagnosed and undiagnosed participants are consistent with a clinically relevant prevalence of autism in the undiagnosed group." As I've mentioned, the picture of 'striking similarities' was far from consistent when comparing RMs across the groups and those statistically significant differences reported on between diagnosed and self-identifying autism. Added to the fact that authors zoomed in on RMs without too much clinical focus on the other elements to autism, and the 'clinically relevant' picture is also far from complete based on this study alone. Indeed, other text in the discussion provide further clues as to the probable inclination of the authors: "We believe that this study in part reached the “lost generation” of autistic adults... many of whom appear to have turned to social media for support and kinship, sometimes after many disappointing encounters with clinicians and scientists." Emotive language such as 'Lost generation' really shouldn't be in a science paper without [strong] corresponding evidence.
What else? Well the authors did acknowledge some shortcomings in their study: "the on line format limited our ability to ascertain that robust diagnostic procedures had been used in all cases" and: "The self-report format also makes it possible that some participants erroneously reported an official diagnosis" (erroneously?) but perhaps more is needed to be said about participants ("the vast majority were indeed very cognitively able") and onward the applicability of results to other parts of the autism spectrum. It would also have been useful to include a few other (self-report) measures of other conditions/labels where autistic characteristics overlap, just to see...
I do think Wiskerke et al have tapped into a increasingly important research 'need' for some of those on the autism spectrum - masking - and how such behaviour does seem to impact on quality of life for quite a few people. We need a lot more research on this topic, and yes, there also needs to be some further analysis of what social accommodations could be made too, bearing in mind such understanding needs to come from lots of different quarters of society (see here). I'd also like to acknowledge the fact that one of the authors on the Wiskerke took the time to converse (on Twitter) with me about their paper, which was rather encouraging.
But still, I can't shake the idea that the methodological shortcomings of this study and the sweeping interpretations imply caution before any generalisations are made as a result. The fact also remains that self-identifying as being autistic/having autism is not the same as receiving a formal diagnosis of autism, however much people might want this to be true or find 'kinship' with the autism spectrum...
 Wiskerke J. et al. Camouflaging of repetitive movements in autistic female and transgender adults. bioRxiv. 2018. Sept 10.
 Mandy W. et al. Sex differences in autism spectrum disorder: evidence from a large sample of children and adolescents. J Autism Dev Disord. 2012 Jul;42(7):1304-13.
 Kupferstein H. Evidence of increased PTSD symptoms in autistics exposed to applied behavior analysis. Advances in Autism. 2018; 4: 19-29.