Sunday, 25 March 2012

Labels and lumping: is autism common in schizophrenia?

As a species, we love our labels. I'm not talking about your fashion labels or anything like that but rather our love of compartmentalising things; to divide them up into groups or categories, put them in a box and with the giant social marker pen of the time give them a descriptor.

Labels have had an absolutely vital relationship to autism and how it has been viewed down the years. Indeed the proposed changes to the way DSM labels autism (DSM-5) have been fodder for discussion after discussion in many an online and print forum. I might just throw this paper by McPartland and colleagues* into the mix given the column inches that some of the authorship team have created with certain soundbites.

It is with labels in mind that I would like to discuss this paper** by Unenge Hallerbäck and colleagues who asked: is autism spectrum disorder common in schizophrenia? Before going to work on the paper and its very interesting and possibly contentious findings, I did find the thesis of Dr Unenge Hallerbäck online (see here) which, if you have the time, is certainly worth a read.

A summary of the research:

  • The aim of the study was to look at the rates of autism spectrum conditions in a cohort of people diagnosed with schizophrenia and whether the presence of autism is more or less common in any sub-type of schizophrenia and vice-versa. I suppose to be accurate I should be using the term schizophrenia spectrum disorder (SSD) as per the realisation that health is not necessarily all about absolutes but rather degrees and spectrums.
  • A participant group of 46 young adults with a diagnosed SSD were included in the study. Their initial diagnosis was evaluated using the SCID. The parents of 32 participants agreed to complete the DISCO-11, a semi-structured interview covering a 'spectrum' of clinical domains with autism as a focus. Participants also completed the Autism Quotient (AQ) for a more personal view.
  • The results: most participants' diagnoses (and their variants) were corroborated by the SCID. Of the 32 parental reports via the DISCO-11, 41% of these participants had "an algorithm diagnosis of ASD". With specific regards to the confirmed diagnosis via the SCID and where parental data was available (n=23), 52% fulfilled the DISCO-11 diagnosis of ASD. Indeed the authors note that within the SCID diagnosis of paranoid schizophrenia, 60% of participants had an algorithm diagnosis of ASD too. Based on the Gillberg criteria for Asperger syndrome, five participants (all male) from the participant group could be diagnosed with Asperger syndrome (AS).

Agreeing with the authors, over 40% of their participants with schizophrenia also presenting with symptoms concordant to a diagnosis of autism spectrum disorder, is quite a high prevalence. Obviously the numbers of participants for whom complete data was available were relatively low. That combined with the use of retrospective interview introducing confounders like recall bias, means some caution needs to be applied to the current findings.

The first thought passing through my mind is the exclusionary criteria normally applied to the great label-givers like DSM-IV when it comes to autism and AS; as in, if schizophrenia is present, don't bother trying to diagnose an autism spectrum condition unless something like AS was clearly apparent before the onset of schizophrenia symptoms. Both Fitzgerald and Corvin*** (full-text) and Dr Tom Berney**** (full-text) provide quite good overviews of how this rule might apply in clinical practice alongside some of the potential pitfalls of mistaking AS for say, psychosis.

My second thought is not so much a scientific analysis but rather some cultural questions: how would people feel about autism being quite intricately linked to schizophrenia and vice-versa? Are we indeed seeing the diagnostic merry-go-round potentially reverting back to the 'olden days' and autism as childhood schizophrenia and beyond? What would happen to the rates of autism if the exclusionary clause on schizophrenia were no longer present in diagnostic manuals? I pass no opinion by the way, but will refer you to this paper by King and Lord***** as a possible clue to the future direction of the great psychiatric labeling machine.

As much as the current paper is interesting it is not the first time in recent research history that autism and schizophrenia have been 'overlapped' particularly as maturation kicks in and children progress through infancy into adolescence and adulthood and their behavioural presentation changes. Indeed outside of diagnosis, there is quite a bit of evidence to suggest that the overlap extends well beyond just diagnostic circles into areas such as genes and biochemistry. Do I even mention one of my real areas of interest on gluten- and casein-free dietary intervention for autism sprouting from the earlier work of the late Curt Dohan in schizophrenia?

We have to be careful when looking at any similarities and differences between labels like autism and schizophrenia. I've pretty much exhausted the times that I've said that autism is not seemingly protective of any other condition, which should surely also include schizophrenia with the current diagnostic caveats taken into consideration. If there is a positive side to any attempt to 'lump' the two conditions into some kind of 'spectrum' it would probably be the wealth of research undertaken on both conditions and how each could potentially inform the other. Staying out of the pharmacotherapy side of things (e.g. neuroleptic use), I'm thinking about the five serum (and one urinary) biomarkers study published not so long ago on schizophrenia and whether the diagnostic (and pathological) implications of that work might further inform at least some cases of autism?

To finish, Led Zeppelin ("who were they Daddy?") and a question: how long has it been since you've rock n' roll-ed? If the answer is too long, then clear a space and let Jimmy and the boys help with that 3 minute workout.

* McPartland JC. et al. Sensitivity and Specificity of Proposed DSM-5 Diagnostic Criteria for Autism Spectrum Disorder. Journal of the American Academy of Child & Adolescent Psychiatry. March 2012.
DOI: 10.1016/j.jaac.2012.01.007

** Unenge Hallerbäck M. et al. Is autism spectrum disorder common in schizophrenia? Psychiatry Research. March 2012

*** Fitzgerald M. & Corvin A. Diagnosis and differential diagnosis of Asperger syndrome. Advances in Psychiatric Treatment. 2001; 7: 310-318
DOI: 10.1192/apt.7.4.310

**** Berney T. Asperger syndrome from childhood into adulthood. Advances in Psychiatric Treatment. 2004; 10: 341-351
DOI: 10.1192/apt.10.5.341

***** King BH. & Lord C. Is schizophrenia on the autism spectrum? Brain Research. 2011; 1380: 34-41