|The night is darkest just before the dawn.|
That was one of the primary conclusions made in the paper by Adam Helles and colleagues  who prospectively followed a group of males diagnosed with Asperger syndrome (AS) in childhood into adulthood covering a period of some 20 years. I believe the starting point of this study has been seen before in the peer-reviewed literature in the paper by Cederlund & Gillberg  (open-access here) (a paper which takes me back to my own PhD days with it's important influence to some of my work). Other follow-ups have also been reported .
Looking at the diagnostic stability of AS, Helles et al noted that compared with baseline where all participants fulfilled diagnostic criteria, at follow-up (two follow-ups actually) there was a "significant decrease in the rate of cases fulfilling any PDD diagnosis according to the DSM-IV, from 91% at T1 [time 1] to 76% at T2 [time 2] in the 47 cases followed up twice". The decline in cases according to the Gillberg criteria was even more stark (82% at T1 and 44% at T2).
Researchers also noted a few other potentially important points in their findings such that: "Severity of autism spectrum symptoms at T1 was the main predictor of diagnostic stability at T2" and a fifth of those who met criteria for DSM-IV criteria for a PDD diagnosis "did not meet DSM-5 ASD criteria although they had marked difficulties in everyday life". This last point has been mentioned by other authors (see here).
There are a few ways one could take the Helles findings. One could see it as further evidence of the fluidity of presented symptoms when it comes to the autism spectrum as per other discussions in this area (see here). You might even view it as an extension of all that chatter on something like differing developmental trajectories along the autism spectrum (see here) or 'optimal outcome' and autism (see here) albeit without the focus on early intervention as potentially being involved (see here) as far as we know. Indeed, one has to wonder whether for those not meeting the diagnostic criteria as they age and mature, this may in part be because of the various strategies learned over a lifetime to overcome some of the barriers posed by the diagnosis?
But I can also see how for some people such research might be less well-received particularly when added to the 'disappearance' of the term Asperger syndrome from the latest revision of DSM (DSM-V). The paper by Spillers and colleagues  described concerns about "identity, community, the cure movement, and services" following the DSM-5 changes when talking to people on the autism spectrum. I wonder how the Helles findings on 'falling out of the spectrum' diagnostically speaking for some, might have similar tones if and when discussed.
Accepting that the Helles findings were eventually based on quite a small participant group and their insinuation that not reaching the diagnostic thresholds for something like Asperger syndrome does not imply a life free of some of the more 'disabling' aspects on and around the diagnosis (yes, including various comorbidity), I do think there is more to see in this area. The realisation that we know so little about the autism spectrum in the long-term  and how behaviours ebb and flow, that our systems of diagnosis might not necessarily be as robust as we want them to be (see here) and the continued alliance between diagnosis and service receipt excluding many at the diagnostic periphery all come into play. With all the research data collected down the years, one suspects that with a little bit of organisation and willingness to plough some financial and other resources into this issue, further insight into exactly how stable an autism diagnosis might be and for who should be fairly readily available...
Music to close, and having enjoyed the impressive tones of Sheryl Crow last evening, a song most parents will have a heard a few times: Real Gone.
 Helles A. et al. Asperger syndrome in males over two decades: stability and predictors of diagnosis. Journal of Child Psychology and Psychiatry. 2014. 3 October.
 Cederlund M. & Gillberg C. One hundred males with Asperger syndrome: a clinical study of background and associated factors. Dev Med Child Neurol. 2004 Oct;46(10):652-60.
 Cederlund M. et al. Asperger syndrome and autism: a comparative longitudinal follow-up study more than 5 years after original diagnosis. J Autism Dev Disord. 2008 Jan;38(1):72-85.
 Spillers JL. et al. Concerns about identity and services among people with autism and Asperger's regarding DSM-5 changes. J Soc Work Disabil Rehabil. 2014;13(3):247-60.
 Howlin P. et al. Cognitive and language skills in adults with autism: a 40-year follow-up. J Child Psychol Psychiatry. 2014 Jan;55(1):49-58.
Adam Helles, Carina I. Gillberg, Christopher Gillberg, & Eva Billstedt (2014). sperger syndrome in males over two decades: stability and predictors of diagnosis Journal of Child Psychology and Psychiatry : doi: 10.1111/jcpp.12334