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