Tuesday, 31 January 2012

How many adults have autism in the UK: part 2

A quick post this one based on some new data recently published estimating the prevalence of autism in adults in the UK. Regular readers might have seen this topic covered previously in this post and this report * from 2009 which estimated the prevalence of autism in adults in the UK to be 1%.

The revised report** (full-text) extends the dataset with the addition of further interviews and suggests that autism (or rather an autism spectrum condition, ASC) may be more widespread amongst people diagnosed with a learning disability living either at home or in 'communal care establishments'. The revised prevalence figure among adults aged 18 or over is 1.1%.

There are a few other interesting facts to come from this new information including:

  • Based on the combined prevalence data, the rate of ASCs in men was 2.0% and in women 0.3%. 
  • The reported prevalence of ASCs among people with learning disability based in either a home or residential setting was 35.4% and 31% respectively. 
  • When specifically looking at those with a learning disability and either home-based or in a residential setting, the rates according to gender were: home: men = 41.5% vs. women = 28.9% and residential: men = 31.1% vs women 30.9%.
  • There were no statistically significant differences across ethnicity, although prevalence rates between Whites and those of South Asian descent differed (1.2% vs. 0.8%).
  • Highest ASC prevalence was noted among people with more profound learning disability.

Noting that ADOS was used as part of this study and assuming that this did not include the most recent revisions to the scoring algorithm, the prevalence data produced in this study is based on DSM-IV criteria for diagnosis. In light of the various discussions on-going regarding what might happen if an unchanged DSM-V is rolled out, I do wonder how adult prevalence estimates of autism in future may pan out. I suppose the good thing about the current studies by Brugha and colleagues is that they potentially offer a direct comparison against the new DSM-V criteria, should anyone wish to undertake a reanalysis of this population in future.

*  Brugha T. et al. Autism Spectrum Disorders in adults living in households throughout England. Report from the Adult Psychiatric Morbidity Survey 2007. England: The NHS Information Centre for health and
social care, 2009

** Brugha T. et al. Estimating the prevalence of Autism Spectrum Conditions in adults: Extending the 2007 Adult Psychiatric  Morbidity Survey. England: The NHS Information Centre for health and
social care, 2012