ADHD and chronic tic disorder

"Compared with controls, children with ADHD [attention-deficit hyperactivity disorder] were 4.1 (95% CI 1.1 to 14.1) times more likely to have CTD [chronic tic disorder] at age 7, and 5.9 (95% CI 1.6 to 17.9) times more likely at age 10."

That was one of the results observed by William Poh and colleagues [1] who set out to look at both the prevalence of chronic tic disorder (CTD) in their cohort of children diagnosed with ADHD (n=179) compared with asymptomatic (no ADHD) controls (n=212), and also any "additional psychiatric and functional burden of CTD in children with ADHD."

Chronic tic disorder (CTD) includes quite a bit under the label: "chronic motor tic disorder, chronic vocal tic disorder or Tourette syndrome" but the primary linking behaviours are quick, involuntary movements or sounds displayed/vocalised with seemingly no reason or goal. I've talked about tic disorder before on this blog (see here and see here); discussions that have also mentioned ADHD occurring alongside tic disorder so this isn't necessarily a new area of investigation [2].

Alongside finding that kids with ADHD are quite a bit more likely to present with CTD, researchers also found that ADHD + CTD seemed to be associated with other issues as per their experiencing "higher rates of internalising disorders and peer problems, and poorer quality of life than those with ADHD alone." I suppose, given the quite overt life-changing effects that a tic disorder can have, such observations are perhaps not unexpected.

"Clinicians need to consider CTD in both the initial assessment and ongoing management of children with ADHD, and address both the symptoms and the associated impairments." I don't think anyone would disagree with the concluding sentiments discussed by Poh et al. One area in particular that should not be neglected is the possibility that for some at least, tic disorder both inside and outside the context of ADHD might potentially have a bacterial origin (see here) and as such is testable and possibly treatable...

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[1] Poh W. et al. Chronic tic disorders in children with ADHD. Arch Dis Child. 2018 Jan 9. pii: archdischild-2017-314139.

[2] Martino D. et al. Tourette Syndrome and Chronic Tic Disorders: The Clinical Spectrum Beyond Tics. Int Rev Neurobiol. 2017;134:1461-1490.

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The PANDAS hypothesis is supported

PANDAS - pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection - is, as the name suggests, a condition / group of conditions? characterised by bacterial infection, or response to bacteria infection, leading to behavioural / psychiatric presentation(s).

Although fairly widely accepted (at least in the United States) there are some that still question this diagnosis and the idea that infection or response to infection can affect functioning in many more ways than just the somatic. There are, I might add, other examples of this in the clinical literature (see here).

The paper by Sonja Orlovska and colleagues [1] should put a few minds at rest with their 'large-scale' findings that "individuals with a streptococcal throat infection had elevated risks of mental disorders, particularly OCD [obsessive compulsive disorder] and tic disorders"; both key facets of a diagnosis of PANDAS. The additional finding that "nonstreptococcal throat infection was also associated with increased risks, although less than streptococcal infections for OCD and any mental disorder" adds something further to this area.

So, examining one of those oh-so important Scandinavian population registries - this time in Denmark - individuals with "registration of a streptococcal test" were followed up for "a diagnosis of any mental disorder, OCD, or tic disorders." The numbers of participants eventually included were in the hundreds of thousands (+600K) about half of whom at evidence of at least one positive strep test. The authors found that: "Individuals with a positive streptococcal test result had an increased risk of any mental disorder..., particularly of OCD... and tic disorders..., compared with individuals without a streptococcal test."

These are important results. Reiterating the title of this post, the concept of PANDAS is supported by the Orlovska findings. Noting the name Michael Benros on the authorship group of this current paper - someone who has previously explored the possibility that immune function/dysfunction can impact on psychiatry - I daresay that the previous ideas on how infection can affect cognitive abilities for example, (see here) are further extended by this work. Not least that possible identification of bacterial infections as one *cause* of issues such as OCD or tics gets a boost; as does the idea that treating said infections might lead to some rather interesting outcomes. There could also be tie-ups with specific diagnostic labels too (see here)...

To close, there is an election here in Blighty today, so here is party political broadcast for the largest party in the country: The ‘Can’t Be Arsed’ Party. Please exercise your democratic right.

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[1] Orlovska S. et al. Association of Streptococcal Throat Infection With Mental Disorders. JAMA Psychiatry. 2017. May 24.

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Orlovska, S., Vestergaard, C., Bech, B., Nordentoft, M., Vestergaard, M., & Benros, M. (2017). Association of Streptococcal Throat Infection With Mental Disorders JAMA Psychiatry DOI: 10.1001/jamapsychiatry.2017.0995

Siblings of probands with autism: preferential screening suggested?

"Psychiatric and neurodevelopmental disorders cluster among siblings of probands with ASD [autism spectrum disorder]."

That was the research bottom line presented in the paper by Elina Jokiranta-Olkoniemi and colleagues [1] who extracted data from the Finnish Prenatal Study of Autism and Autism Spectrum Disorders (FIPS-A). FIPS-A has been mentioned previously on this blog (see here) but this time around the aim was to look not at the various risk factors potentially associated with receipt of an autism diagnosis, but rather how siblings of those with autism might require some preferential screening for a variety of potential psychiatric and/or neurodevelopmental labels. I know that might not make great reading but burying ones head in the sand is not likely to do anyone any good.

With a starting participant sample in the thousands - "31, 2005, who received a diagnosis of ASD" - researchers matched cases with asymptomatic (not autism) controls to a ratio of 4:1. "This nested case-control study included 3578 cases with ASD with 6022 full siblings and 11 775 controls with 22 127 siblings from Finnish national registers." Various psychiatric and behavioural diagnoses were searched for among siblings of those with autism and compared with rates among control participant siblings. An adjusted risk ratio was generated; authors also taking into account the various ASD sub-diagnoses (many of which have been subsumed under the latest DSM-5 definition of autism).

Results: as per the opening sentence, siblings of those diagnosed with autism were at a significantly increased risk of various psychiatric and neurodevelopmental outcomes. Around 10% of siblings of those with autism were diagnosed with an ASD tallying with what has been previously reported in the peer-reviewed literature on familial recurrence (see here). This compared with the similarly standard 1% of siblings of asymptomatic controls who were diagnosed with an ASD. Actually, 1% might not be the standard any longer...

Other associations were also noted; so learning and coordination disorders were reported in around 15% of siblings of those with autism compared with 6% in control siblings. Similar patterns were noted with regards to attention-deficit hyperactivity disorder (ADHD) and interestingly, tic disorders too (a particular interest to this blog). The bottom line again being that siblings of those with autism might have something of an increased risk of receiving various developmental or behavioural diagnoses.

The authors conclude that when it comes to discussions about aetiology, there may be some common risk factors that predispose to the various labels included for study. Of course this is not necessarily new news as per other research looking at 'overlapping' structural genetics for example (see here) and the realisation that a diagnosis of autism is by no means protective against other conditions occurring (see here). Indeed, other research published in the same journal hints at some important genetic overlap when it comes to autism and other diagnoses [2] which may be particularly relevant (see here). If there is anything that I would add to any future research agenda it would be some way of incorporating the concept of the broader autism phenotype (BAP) into proceedings (see here) and also the inclusion of more somatic diagnoses (see here) as well as neurodevelopmental and psychiatric as a means to search for overlapping variables. As for clinical practice, well to reiterate again, the implication is to potentially offer preferential screening for a variety of neurodevelopmental and/or psychiatric labels when autism appears in the family...

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[1] Jokiranta-Olkoniemi E. et al. Risk of Psychiatric and Neurodevelopmental Disorders Among Siblings of Probands With Autism Spectrum Disorders. JAMA Psychiatry. 2016. May 4.

[2] Goes FS. et al. Exome Sequencing of Familial Bipolar Disorder. JAMA Psychiatry. 2016. April 27.

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Jokiranta-Olkoniemi, E., Cheslack-Postava, K., Sucksdorff, D., Suominen, A., Gyllenberg, D., Chudal, R., Leivonen, S., Gissler, M., Brown, A., & Sourander, A. (2016). Risk of Psychiatric and Neurodevelopmental Disorders Among Siblings of Probands With Autism Spectrum Disorders JAMA Psychiatry DOI: 10.1001/jamapsychiatry.2016.0495

9-12% of those with autism also have a tic disorder

The title of this brief post reflects the findings reported by Efrosini Kalyva and colleagues [1] who undertook a review looking at the co-occurrence of autism spectrum disorder (ASD) and Tourette syndrome (TS) including the presence of tic disorder (part and parcel of the diagnosis of TS). The authors concluded that although the overlap rates might, to some degree, be tied into the "level of ASD severity" there may be quite a bit more to do research-wise to look at the hows and whys of the overlap.

I was not surprised to read such results. As per musings on this topic before on this blog (see here) tics - vocal or physical that can be both simple and complex - have been reported in about one in ten children and young adults diagnosed with ASD. Further: "Tic awareness is limited in ASD." [2] I might add that as and when autism appears with certain other comorbidities, the likelihood of tic disorder appearing jumps even further (see here).

Kalyva et al also suggested that anywhere between 4-20% of those with autism may also present with TS (reiterating the issue of 'level of ASD severity' as being a mediating factor). Again, one can only assume that such reporting should have implications for preferential screening where autism is diagnosed and onwards an appropriate assessment of the necessity of intervention (and not just of the pharmacological kind). I might also add that to talk about autism and TS appearing together does not necessarily mean that this reflects a homogeneous phenotype [3]. The concept of 'autism plus' [4] marches on...

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[1] Kalyva E. et al. A review of co-occurrence of autism spectrum disorder and Tourette syndrome. Research in Autism Spectrum Disorders. 2016; 24: 39-51.

[2] Kahl U. et al. Tic Phenomenology and Tic Awareness in Adults With Autism. Movement Disorders Clinical Practice. 2015. March 30.

[3] Zappella M. Early-onset Tourette syndrome with reversible autistic behaviour: a dysmaturational disorder. Eur Child Adolesc Psychiatry. 2002 Feb;11(1):18-23.

[4] Posserud M. et al. Autism traits: The importance of "co-morbid" problems for impairment and contact with services. Data from the Bergen Child Study. Res Dev Disabil. 2016 Jan 27. pii: S0891-4222(16)30002-6.

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Kalyva, E., Kyriazi, M., Vargiami, E., & Zafeiriou, D. (2016). A review of co-occurrence of autism spectrum disorder and Tourette syndrome Research in Autism Spectrum Disorders, 24, 39-51 DOI: 10.1016/j.rasd.2016.01.007