This type of research - when it shows some positive correlation - kinda reiterates that when we talk about autism, we aren't so much talking about a single homogeneous condition, but perhaps rather a range of conditions which share some common behavioural characteristics summed up by the diagnostic label autism. I suppose its a bit like calling fizzy drinks (soda) and summer fruits 'sweet' but also realising that soda and fruit are quite different things outside of their sweet taste (if that makes any sense).
With this in mind, the publication of an interesting paper by Francisca van Steensel and colleagues** (full-text) on the presence of autistic traits in children with various anxiety disorders is quite an interesting read. The paper is open-access and suggests that whilst not necessarily fulfilling all the criteria for autism or the autism spectrum, children diagnosed with various anxiety-related conditions do seem to present more frequently with autism traits as described by their previous developmental history and current behaviour. There is another paper from the same authors*** which might also be relevant but I'm going to leave that for this post.
A short summary:
- Parental interviews made on behalf of 42 children (mean age 12 years) diagnosed with one or more anxiety disorder were compared with interviews for 42 asymptomatic control children (mean age 11 years) based on the Autism Diagnostic Interview-Revised (ADI-R) and Children’s Social Behavioral Questionnaire (CSBQ) probing offspring early and current autism traits respectively.
- Results: children with anxiety related disorders were reported to show/have shown an increased number of autism related behaviours compared with controls.
- Based on the ADI-R algorithm scores for the triad of core autism domains, over a third of children with an anxiety disorder surpassed one or more cutoff points for the presentation of autism-like behaviours during their developmental history. This was compared with none of the control group. Indeed, one child in the anxiety group surpassed thresholds on all 3 domains. Statistically speaking, the anxiety group scored significantly higher across all autism domains than the control group.
- Based on CSBQ scores, the anxiety group also presented with a greater number of current autism-like behaviours than the control group. Again, nearly a third of children with anxiety related conditions "had scores that fell in the ASD range".
- Interestingly, when looking at current anxiety symptoms based on the Screen for Child Anxiety Related Emotional Disorders (SCARED-71), several types of anxiety disorder correlated with scores of particularly current autism-like traits including panic disorder, generalised anxiety disorder, social anxiety disorder and separation anxiety disorder (all significant at p equal or less than 0.01).
I don't want to make too much out of this current paper bearing in mind the small participant group included. That being said however, this is not the first time that anxiety disorders have been looked at with autism traits in mind (see here).
Aside from important considerations such as (a) screening for autism in children with anxiety disorder brought about by this kind of research, assuming good validity of the instruments used, and not 'over-screening' and (b) the possibility of shared biochemistry, genes, etc., I started to wonder about what these results might mean for people with an autism spectrum condition. So for example, do the results work in reverse, and those with autism are perhaps more prone to an anxiety disorder? Certainly I don't think I can stress enough the effects that anxiety seems to have on many people with autism. In some cases dare I suggest that it is one of the most debilitating aspects to autism. The question is whether such issues merit a separate diagnosis of anxiety disorder and whether for example, managing the anxiety might have knock-on effects to other more core presentation?
On a final note, I couldn't help but raise a smile at the results presented by Pobbe and colleagues**** (full-text) on anxiety measurement in the Dangermouse that is the BTBR mouse model of autism. Not specifically relevant to the latest work but interesting insofar as the potential usefulness of the BTBR model.
Now, clear some space, break out the air guitar and let Bryan tell you all about his summer of '69.
* Coombs E. et al. An investigation into the relationship between eating disorder psychopathology and autistic symptomatology in a non-clinical sample. The British Journal of Clinical Psychology. 2011; 50: 326-338.
** van Steensel. et al. Autism spectrum traits in children with anxiety disorders. JADD. June 2012.
*** van Steensel FJ. et al. Anxiety and quality of life: clinically anxious children with and without autism spectrum disorders compared. Journal of Clinical Child & Adolescent Psychology. July 2012.
**** Pobbe RL. et al. General and social anxiety in the BTBR T+ tf/J mouse strain. Behavioral Brain Research. 2011; 216: 446-451.
van Steensel FJ, Bögels SM, & Wood JJ (2012). Autism Spectrum Traits in Children with Anxiety Disorders. Journal of autism and developmental disorders PMID: 22733297
I'm always a bit cautious about these papers.ReplyDelete
If you look for a correlation between any two psych symptoms or disorders, there is usually a correlation, people with X are more likely to suffer from Y, that's true 90% of the time.
So I wonder if it's specific to anxiety and autism? Is the correlation between autism and anxiety stronger than for, say, ADHD and anxiety; or autism and depression?
If not, the correlation is still true, but it's a bit misleading to focus just on this one correlation.
Many thanks for the comment Neuroskeptic.ReplyDelete
Correlation is generally a lovely way of 'putting the blinkers on' with regards to other potential effectors and seeing the bigger picture. Autism research is plagued by correlational research - paternal age, maternal obesity and metabolic disorder risk, gestational vitamin intake, etc, etc. I suppose most of it comes from just not knowing, and in particular not knowing where to start.
In terms of the anxiety link, I do believe this has an important connection with autism. Not necessarily exclusive it has to be said - but given that anxiety issues can often be one of the main factors affecting quality of life for people with autism, and as one commentator has noted, anxiety is perhaps expected as arising from the core diagnostic criteria of autism (resistance to changes / repetitive actions), this latest focus seems justified.
Indeed whether one day anxiety in some shape or form might even enter the diagnostic criteria for autism (in adults?) one day, is a question that I've pondered for quite a while.
Chicken and egg situation. This research from Robert Bransfield sheds more light on infectious origins with many illnesses but including ASD http://benthamscience.com/open/toneuj/openaccess2.htm The Psychoimmunology of Lyme/Tick-Borne Diseases and its Association with Neuropsychiatric Symptoms, 2012; 6: Pp. 88-93ReplyDelete
Robert C. Bransfield
Published Date: (05 October, 2012)
Disease progression of neuropsychiatric symptoms in Lyme/tick-borne diseases can be better understood by greater attention to psychoimmunology. Although there are multiple contributors that provoke and weaken the immune system, infections and persistent infections are significant causes of pathological immune reactions. Immune mediated effects are a significant contributor to the pathophysiological processes and disease progression. These immune effects include persistent inflammation with cytokine effects and molecular mimicry and both of these mechanisms may be present at the same time in persistent infections. Sickness syndrome associated with interferon treatment and autoimmune limbic encephalopathies are models to understand inflammatory and molecular mimicry effects upon neuropsychiatric symptoms. Progressive inflammatory reactions have been proposed as a model to explain disease progression in depression, psychosis, dementia, epilepsy, autism and other mental illnesses and pathophysiological changes have been associated with oxidative stress, excitotoxicity, changes in homocysteine metabolism and altered tryptophan catabolism. Lyme disease has been associated with the proinflammatory cytokines IL-6, IL-8, IL-12, IL-18 and interferon-gamma, the chemokines CXCL12 and CXCL13 and increased levels proinflammatory lipoproteins. Borrelia burgdorferi surface glycolipids and flagella antibodies appear to elicit anti-neuronal antibodies and anti-neuronal antibodies and Borrelia burgdorferi lipoproteins can disseminate from the periphery to inflame the brain. Autism spectrum disorders associated with Lyme/tick-borne diseases may be mediated by a combination of inflammatory and molecular mimicry mechanisms. Greater interaction is needed between infectious disease specialists, immunologists and psychiatrists to benefit from this awareness and to further understand these mechanisms. Bransfield has donme much work in the field of Autism and especially Lyme induced Autism.
Many thanks for the comment Joanne.ReplyDelete
I have talked about Lyme disease previously on this blog:
and indeed the potential double-edged sword that is antibiotics (used to treat such infections) and autism: