Thursday, 21 August 2014

Autism, ADHD and allergy: Taiwan and big data (again)

"Children with ADHD [attention-deficit hyperactivity disorder] or ASD [autism spectrum disorder] had an increased risk of allergic comorbidities, and those with both ADHD and ASD had the highest".
"You built a time machine.. out of a DeLorean"

That was the conclusion arrived at in the paper by Ting-Yang Lin and colleagues [1]. For regular readers of this blog, this was yet another example of how Taiwan leads the way when it comes to the concept of 'big data' specifically employed with neurodevelopmental conditions in mind. That Taiwan National Health Insurance Research Database is proving to be a very valuable resource indeed.

A few details from the latest study:

  • "5386 children aged less than 18 years with ADHD alone, 578 with ASD alone, 458 with ADHD + ASD, and 25,688 non-ADHD/ASD age- and sex-matched (1:4) controls were enrolled in our study". I don't think anyone can say that this was an underpowered study.
  • The presence of various allergic diseases including asthma and atopic dermatitis were looked at among participant groups and compared.
  • Results: Odds ratios (ORs) suggested that the autism, ADHD and combined autism + ADHD groups were all more likely to present with comorbid allergic conditions compared to asymptomatic controls. This, taking into account "age, sex, and level of urbanization". The combined group seemed to be a greater risk of allergic disease than the autism or ADHD alone groups (OR: 2.2 95% CI: 1.83–2.79).
  • "ASD children with more allergic comorbidities were associated with a greater likelihood of ADHD". 

Quite a bit of this data taps into previous findings based on the examination of the Taiwanese insurance database insofar as the link between asthma (see here and see here) and neurodevelopmental diagnoses, so no real surprises there. The intriguing prospect that an increasing allergic burden in cases of autism seemed to elevate the risk of comorbid ADHD being present is the value-added part to the Lin study. What autism research is starting to understand is that comorbidity is quite a big issue (see here) and, outside of learning disability (see here) and epilepsy (see here), ADHD seems to figure quite prominently (see here). 

Bearing in mind that correlation is not the same as causation, I'd like to see quite a bit more investigation into that autism - allergy - ADHD relationship talked about by Lin et al. Genetics might be a good starting point as per the growing realisation about 'common ground' when it comes to various behaviourally-defined conditions (see here). The recent paper looking at the possible genetics of schizophrenia [2] linking into immune functions (see here) might set the tone for further inquiry in this area. Given the growing body of research looking at immune function and autism (see here and see here for examples) one might see how allergic diseases may show more than a passing connection to at least some cases.

I'd also be minded to suggest that environment might also be something to look at with this possible relationship in mind. Food is something of a potential common denominator when it comes to at least some autism and some ADHD (see here) so perhaps further investigation might be required there. The paper by de Theije and colleagues [3] talked quite a bit about food allergy and autism and ADHD for example. I don't know enough about how food might tie into something like asthma or atopic eczema as to present any knowledgeable information about links. I'd hazard a guess that looking at something like the gastrointestinal (GI) tract and things like the gut microbiota [4] might also be worthwhile.

Music to close, and something uplifting from The Smiths...

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[1] Lin T-Y. et al. Autistic spectrum disorder, attention deficit hyperactivity disorder, and allergy: Is there a link? A nationwide study. Research in Autism Spectrum Disorders. 2014; 8: 1333-1338.

[2] Schizophrenia Working Group of the Psychiatric Genomics Consortium. Biological insights from 108 schizophrenia-associated genetic loci. Nature. 2014; 511: 421-427.

[3] de Theije CG. et al. Food allergy and food-based therapies in neurodevelopmental disorders. Pediatr Allergy Immunol. 2014 May;25(3):218-26.

[4] Molloy J. et al. The potential link between gut microbiota and IgE-mediated food allergy in early life. Int J Environ Res Public Health. 2013 Dec 16;10(12):7235-56.

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ResearchBlogging.org Lin, T., Lin, P., Su, T., Chen, Y., Hsu, J., Huang, K., Chang, W., Chen, T., Pan, T., Chen, M., & Bai, Y. (2014). Autistic spectrum disorder, attention deficit hyperactivity disorder, and allergy: Is there a link? A nationwide study Research in Autism Spectrum Disorders, 8 (10), 1333-1338 DOI: 10.1016/j.rasd.2014.07.009

Wednesday, 20 August 2014

ADHD in DSM-5: what did you think would happen?

"Our results, combined with previous findings, suggest a 27% increase in the expected prevalence of ADHD [attention-deficit hyperactivity disorder] among young adults, comparing DSM-IV to DSM-5 criteria". So said the paper by Matte and colleagues [1] who as part of their study looked at "the prevalence of ADHD according to DSM-5 criteria".
Europa @ Wikipedia 

The changes to the diagnosis of ADHD in DSM-5 can be seen here. The main difference between DSM-IV and DSM-5 diagnosis seems to be a change in the maximum age of symptom onset; previously set at 7 years in DSM-IV, now 12 years in DSM-5. This change has been the topic of quite a bit of discussion [2].

I'm going no further in this discussion aside from bringing to your attention an article by Dr Allen Frances who has been more than a little critical of the changes made to DSM in this latest version. To quote: "DSM 5 will likely trigger a fad of Adult Attention Deficit Disorder leading to widespread misuse of stimulant drugs for performance enhancement and recreation and contributing to the already large illegal secondary market in diverted prescription drugs". Accepting that any rise in the use of nootropics is beyond the scope of this post, the increase in expected prevalence reported by Matte and colleagues is not a million miles away from Dr Frances' 2012 prediction...

Music then. Perfect Day by Lou Reed (the BBC version).

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[1] Matte B. et al. ADHD in DSM-5: a field trial in a large, representative sample of 18- to 19-year-old adults. Psychol Med. 2014 Jun 23:1-13.

[2] Cortese S. Are concerns about DSM-5 ADHD criteria supported by empirical evidence? BMJ. 2013 Nov 27;347:f7072.

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ResearchBlogging.org Matte, B., Anselmi, L., Salum, G., Kieling, C., Gonçalves, H., Menezes, A., Grevet, E., & Rohde, L. (2014). ADHD in DSM-5: a field trial in a large, representative sample of 18- to 19-year-old adults Psychological Medicine, 1-13 DOI: 10.1017/S0033291714001470

Tuesday, 19 August 2014

Family processes and trajectory in autism

The paper by Woodman and colleagues [1] looking at trajectory and autism in adolescents and adults is the source material for today's post (another micropost). Concluding that: "Overall, autism symptoms and maladaptive behaviors were observed to improve over the study period" of about 8 years, the authors also reported that "greater improvements were associated with higher levels of maternal praise (based on maternal speech samples) and higher quality mother-child relationships". If I remember correctly, that last sentence on maternal praise being linked to outcome was the topic of some discussion at IMFAR (2014) this year (see here). That alongside some concerns about healthcare provision for adults with autism (see here) which ties in well with the recent revision to the Treating Autism document on health comorbidity in autism (see here).
A word of warning from Alnwick Castle

Whilst treading a little bit carefully in this area, I find the Woodman paper to be intriguing. Not only because their findings provide further support for the fluidity of presentation in autism tied into the concept of stability (see here), but also because of that association between presentation and environment [2].

A quick trawl through the peer-reviewed literature on this topic reveals that family context is something previously covered by this authorship group as per other papers [3]. Some of their other discussions [4] looking at the role of families on autism carry some pearls of wisdom, as for example: "It is important to note that within any family system, transactions among family members are bidirectional. As such, in addition to risks for parental health due to stressful caregiving, high levels of family distress also can create difficulties for the individual with autism". That last paper also talked about the use of a "multi-family group psychoeducation" intervention model (see here) as a means to improve the family dynamic which is something I'd like to see quite a bit more research into.

Music to close, and what else but Praise You by Fatboy Slim...

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[1] Woodman AC. et al. Change in Autism Symptoms and Maladaptive Behaviors in Adolescence and Adulthood: The Role of Positive Family Processes. J Autism Dev Disord. 2014 Jul 29.

[2] Smith LE. et al. Symptoms and behavior problems of adolescents and adults with autism: effects of mother-child relationship quality, warmth, and praise. Am J Ment Retard. 2008 Sep;113(5):387-402.

[3] Smith LE. et al. The family context of autism spectrum disorders: influence on the behavioral phenotype and quality of life. Child Adolesc Psychiatr Clin N Am. 2014 Jan;23(1):143-55.

[4] Smith LE. et al. Adults with autism: outcomes, family effects, and the multi-family group psychoeducation model. Curr Psychiatry Rep. 2012 Dec;14(6):732-8.

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ResearchBlogging.org Woodman AC, Smith LE, Greenberg JS, & Mailick MR (2014). Change in Autism Symptoms and Maladaptive Behaviors in Adolescence and Adulthood: The Role of Positive Family Processes. Journal of autism and developmental disorders PMID: 25070471

Monday, 18 August 2014

ADHD in the prison population: a micropost

"Compared with published general population prevalence, there is a fivefold increase in prevalence of ADHD in youth prison populations (30.1%) and a 10-fold increase in adult prison populations (26.2%)".
"Mianly dry" apparently @ Paul Whiteley

That was the primary conclusion reached in the meta-analysis by Young and colleagues [1] looking at the collected peer-reviewed literature on "the variable prevalence of attention deficit hyperactivity disorder (ADHD) in incarcerated populations".

There is little more for me to say on this topic aside from the fact that as per the paper by Usher and colleagues [2], the presence of ADHD (including sub-threshold signs and symptoms) might have quite a few implications for things like comorbid mental health features [3] and issues like substance abuse [4]. That also: "ADHD symptoms were also found to predict institutional misconduct" is an important point to make without trying to make any sweeping generalisations.

Screening of the prison population for ADHD sounds like it might be a good idea on the basis of the collected data in this area, leading on to further discussions about possible management options. That being said, intervention might not necessarily just include the more traditional pharmacotherapy but as per the important work by Bernard Gesch and colleagues [5] overlapping with the studies from Julia Rucklidge and colleagues (see here), on how good nutrition might also be on the menu. In fact...

To close, the Foo Fighters and Learn to Fly.

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[1] Young S. et al. A meta-analysis of the prevalence of attention deficit hyperactivity disorder in incarcerated populations. Psychol Med. 2014 Apr 7:1-12.

[2] Usher AM. et al. Attention deficit hyperactivity disorder in a Canadian prison population. Int J Law Psychiatry. 2013 May-Aug;36(3-4):311-5.

[3] Kessler RC. et al. The prevalence and correlates of adult ADHD in the United States: results from the National Comorbidity Survey Replication. Am J Psychiatry. 2006 Apr;163(4):716-23.

[4] Harstad E. et al. Attention-deficit/hyperactivity disorder and substance abuse. Pediatrics. 2014 Jul;134(1):e293-301.

[5] Gesch CB. et al. Influence of supplementary vitamins, minerals and essential fatty acids on the antisocial behaviour of young adult prisoners. Randomised, placebo-controlled trial. Br J Psychiatry. 2002 Jul;181:22-8.

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ResearchBlogging.org Young S, Moss D, Sedgwick O, Fridman M, & Hodgkins P (2014). A meta-analysis of the prevalence of attention deficit hyperactivity disorder in incarcerated populations. Psychological medicine, 1-12 PMID: 25066071

Saturday, 16 August 2014

The epidemiology of autism spectrum disorders

A very short post for readers to ponder based on the paper by Amanda Baxter and colleagues [1] who talked about the global epidemiology of the autism spectrum disorders (ASDs).

"In 2010 there were an estimated 52 million cases of ASDs, equating to a prevalence of 7.6 per 1000 or one in 132 persons".

Aside from emphasising the word 'estimated' (I highlighted that), be prepared to see the Baxter paper and that quote cited quite a bit in the peer-reviewed literature in times to come.

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[1] Baxter AJ. et al. The epidemiology and global burden of autism spectrum disorders. Psychological Medicine. 2014. August 11.

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ResearchBlogging.org A. J. Baxter, T. S. Brugha, H. E. Erskine, R. W. Scheurer, T. Vos, & J. G. Scott (2014). The epidemiology and global burden of autism spectrum disorders Psychological Medicine : http://dx.doi.org/10.1017/S003329171400172X

Friday, 15 August 2014

Psychotic experience following childhood neurodevelopmental diagnosis

The paper by Golam Khandaker and colleagues [1] suggesting a higher risk of psychotic episodes (PEs) in early adolescence among those with a diagnosed childhood neurodevelopmental disorder (ND) makes for some interesting reading. Detailing several diagnoses as falling under the banner of neurodevelopmental disorder (autism spectrum, dyslexia, dyspraxia, dysgraphia, dysorthographia, dyscalculia), researchers concluded that: "The risk of PEs was higher in those with, compared with those without, NDs". IQ also seemed to show some connection to risk.
The Flower Seller @ Wikipedia 

A few further details:

  • Based on a cohort of over 8000 children, researchers reported that approximately 6% (487) were "reported to have NDs at age 9 years". By 'reported' they meant that parent's reported these via a questionnaire.
  • PEs "were assessed by semi-structured interviews at age 13 years". IQ and a specific focus on working memory "were measured between ages 9 and 11 years".
  • The authors suggested that the elevated risk of PEs accompanying a diagnosis of ND "is consistent with the neurodevelopmental hypothesis of schizophrenia".

With specific focus on autism as one of the NDs mentioned in the Khandaker study, I was taken back to some interesting work looking at both the overlap between the autism and schizophrenia spectrums (see here) and the initial data talking about Asperger syndrome and first-episode psychosis (see here). Both these areas of work seem to tie into the neurodevelopmental hypothesis talked about by authors, accepting that I am not trying to promote any reunification of the conditions nor making any sweeping generalisations.

I might also bring to your attention another piece of work by Khandaker and colleagues [2] which has been covered on this blog talking about the risk of psychotic episodes in cases of atopic disease such as asthma and eczema. Alongside other work by this group [3] talking about "Early-life exposure to EBV [Epstein-Barr virus]" and prenatal exposure to "a range of infections and inflammatory responses" [4] the emphasis is on how various somatic processes might be involved in bringing someone to a PE, particularly with the immune system as a potentially important player. Perhaps more evidence for a role for inflammation in psychiatry and possibly with overlapping issues [5]. As I've said before on this blog, autism and inflammation is a bit of a growth area in research terms.

I'd like to think that the latest Khandaker findings might be further investigated with a view to looking at both potential mechanism(s) involved in that neurodevelopmental hypothesis of schizophrenia [6] (including genetic and non-genetic factors [7]) and also how prevalent the range of factors the authors have previously identified as being linked to PEs are in conditions such as autism and dyslexia for example. The additional question of whether targeting something like the immune system during 'inflammatory' phases might offset the risk of PEs is a tantalising one.

And speaking of Khandaker, I'm minded to talk soon about even more recent findings from this group [8] on inflammation and psychiatry...

Music then to close. The late Amy Winehouse and Back to Black.

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[1] Khandaker GM. et al. A population-based longitudinal study of childhood neurodevelopmental disorders, IQ and subsequent risk of psychotic experiences in adolescence. Psychol Med. 2014 Apr 25:1-10.

[2] Khandaker GM. et al. A population-based study of atopic disorders and inflammatory markers in childhood before psychotic experiences in adolescence. Schizophr Res. 2014 Jan;152(1):139-45.

[3] Khandaker GM. et al. Childhood Epstein-Barr Virus infection and subsequent risk of psychotic experiences in adolescence: A population-based prospective serological study. Schizophr Res. 2014 Jul 18. pii: S0920-9964(14)00251-5.

[4] Khandaker GM. et al. Prenatal maternal infection, neurodevelopment and adult schizophrenia: a systematic review of population-based studies. Psychol Med. 2013 Feb;43(2):239-57.

[5] Meyer U. et al. Schizophrenia and Autism: Both Shared and Disorder-Specific Pathogenesis Via Perinatal Inflammation? Pediatric Res. 2011; 69: 26R-33R.

[6] Owen MJ. et al. Neurodevelopmental hypothesis of schizophrenia. Br J Psychiatry. 2011 Mar;198(3):173-5.

[7] Zavos HMS. et al. Consistent Etiology of Severe, Frequent Psychotic Experiences and Milder, Less Frequent Manifestations. JAMA Psychiatry. 2014. 30 July.

[8] Khandaker GM. et al. Association of Serum Interleukin 6 and C-Reactive Protein in Childhood With Depression and Psychosis in Young Adult Life. JAMA Psychiatry. 2014. August 13.

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ResearchBlogging.org Khandaker GM, Stochl J, Zammit S, Lewis G, & Jones PB (2014). A population-based longitudinal study of childhood neurodevelopmental disorders, IQ and subsequent risk of psychotic experiences in adolescence. Psychological medicine, 1-10 PMID: 25066026

Thursday, 14 August 2014

Learning disability in autism: how prevalent is it?

"Results showed that 36.8 % of the children met the criteria for ID [intellectual disability], with 60.2 % of these in the mild range (IQ 50-69) and 39.8 % in the moderate range (IQ 35-49)".

That was the finding reported by Mélina Rivard and colleagues [1] looking at the co-occurrence of intellectual disability (also called learning disability here in Blighty) and autism spectrum disorder (ASD) "in young children". Based on an analysis of over 200 children diagnosed with an ASD, researchers recorded various details before participants entry into an "early behavioral intervention program" including those relating to IQ and adaptive behaviours. Most of those children falling into the category of ID were in the 'mild' range (IQ 50-69) as opposed to the moderate range (IQ 35-49).
Roses @ Wikipedia 

This is an important paper insofar as presenting some further details about how widespread ID is in cases of autism. Indeed, a figure hovering somewhere around 30-40% of all cases of autism (accepting the issue of variations in subtypes on the autism spectrum) presenting with ID is pretty much what many people have discussed on the basis of other research in this area [2]. That being said, the recent CDC prevalence estimates (yes, estimates) of autism (see here) kinda hinted that the rates of ID in autism might be on the move as per their reporting: "31% of children with ASD were classified as having IQ scores in the range of intellectual disability (IQ ≤70)" [3]. We'll have to wait and see how this goes alongside the introduction of the DSM-5 diagnostic criteria (see here).

Having reliable data on the rate of ID in autism also goes beyond just knowing how many people fall into that category. When present alongside each other, one might assume that there may be shared factors at work in terms of aetiology as for example, discussed by Srivastava & Schwartz [4]. I've talked a few times on this blog about another triad of symptoms (autism, epilepsy & learning disability) appearing in some quite rare genetic conditions (see here) which provides some interesting details about possible onset and indeed intervention.

That there may also be a greater risk of autism and ID in specific populations is another detail to bear in mind. Take for example the 2013 report on autism in the Somali population in Minneapolis (see here) and the finding: "Somali children with ASD were more likely to also have an intellectual disability than children with ASD in all other racial and ethnic groups in Minneapolis". I say this acknowledging that inferring causation from such epidemiology is not necessarily going to be straight forward.

Perhaps also important is mention of the impact that comorbid ID can have on various other outcomes with autism in mind. Yes, we know that this probably means a greater requirement for service provision (see here) and inevitably this will have an economic cost attached to it (see here). But then there are issues like self-injurious behaviour (see here) and the topic no-one really likes to talk about, early mortality (see here) which might also be differentially affected by the presence of ID, or at least some behaviours which might place someone at greater risk of danger (see here). I personally see these as some of the more important effects of ID on autism.

Eliza Doolittle to finish, and Pack Up.

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[1] Rivard M. et al. Indicators of Intellectual Disabilities in Young Children with Autism Spectrum Disorders. J Autism Dev Disord. 2014 Jul 29.

[2] Chakrabarti S. & Fombonne E. Pervasive developmental disorders in preschool children: confirmation of high prevalence. Am J Psychiatry. 2005 Jun;162(6):1133-41.

[3] Developmental Disabilities Monitoring Network Surveillance Year 2010 Principal Investigators. Prevalence of autism spectrum disorder among children aged 8 years - autism and developmental disabilities monitoring network, 11 sites, United States, 2010. MMWR Surveill Summ. 2014 Mar 28;63(2):1-21.

[4] Srivastava AK. & Schwartz CE. Intellectual disability and autism spectrum disorders: Causal genes and molecular mechanisms. Neurosci Biobehav Rev. 2014 Apr 4. pii: S0149-7634(14)00077-3.

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ResearchBlogging.org Rivard M, Terroux A, Mercier C, & Parent-Boursier C (2014). Indicators of Intellectual Disabilities in Young Children with Autism Spectrum Disorders. Journal of autism and developmental disorders PMID: 25070470