The Essence of Christopher Gillberg’s E.S.S.E.N.C.E. Theory

“While in the past, child psychiatry had little interest in operationalised diagnosis, recent trends have made categorical diagnosis an integral part of everyday clinical and research practice. So focused are we now on the dichotomous distinction between disorder and not disorder that clinics become more and more specialised and cater to the needs of children with ‘autism only’, ‘attention-deficit/hyperactivity disorder/ADHD only’ or ‘Tourette syndrome only’. This has led to a situation in which the diffuseness of disorder has come to be underestimated.

“At the same time, rather belatedly, there is a growing realisation that co-existence of disorders and sharing of symptoms across disorders (so called comorbidity, a misnomer if ever there was one) is the rule rather than the exception” (Gillberg, 2010, p. 1543).

I had the pleasure of meeting and speaking with Dr. Christopher Gillberg earlier this month at a conference on Brain Disorders in La Ciotat, France. Of my own personal history, Gillberg’s book, A Guide to Asperger Syndrome, marked the start of my personal and professional autism journey back in 2003. Alongside Tony Attwood’s book, they were the first two books I read which introduced me to this complex group of conditions known as “autism”. At the time, I was studying psychology and was a low-level ABA therapist working part-time with a one-and-a-half year-old autistic boy. I picked those books up in order to try and better understand him, however I also started my own journey towards diagnosis.

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So needless to say, I was a little awestruck at the prospect of meeting Dr. Gillberg. And I must say, he’s an exceptionally congenial and kind gentleman. I specifically wished to ask him about his opinion on the co-occurrence of schizophrenia in autism, given his extensive clinical experience– but I’ll save that for a later post!

In any case, in my present stage of research, with a manuscript currently under review which focuses on the overlapping genetics of autism, epilepsy, and schizophrenia, the idea of a group of inter-related rather than “comorbid” conditions is appealing. The acronym “ESSENCE” means Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations and refers to:

“the reality of children (and their parents) presenting in clinical settings with impairing child symptoms before age 3 (-5) years in the fields of (a) general development, (b) communication and language, (c) social inter-relatedness, (d) motor coordination, (e) attention, (f) activity, (g) behaviour, (h) mood, and/or (i) sleep” (p. 1543).

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Christopher Gillberg.

Gillberg posits that, while it’s difficult to accurately diagnose a child in the early years of life who comes to a diagnostician’s attention with deficits in any of the above categories, and these difficulties are not specific to ESSENCE alone, they nevertheless may be reliable early markers for later development and diagnosis of any of the following related conditions:

  • Autism
  • ADHD
  • Oppositional Defiant Disorder (ODD)
  • Specific Language Impairment (SLI)
  • Intellectual Disability (mental retardation, otherwise known as “learning disability” in Europe)
  • Nonverbal Learning Disability
  • Tourette’s Syndrome/Tic Disorders
  • Bipolar Disorder
  • Genetic Syndromes (otherwise known as “Behavioural Phenotype Syndromes”)
  • Rare Epilepsy Syndromes
  • Reactive Attachment Disorder

I would imagine, though it’s not listed, it could also include other specific learning disabilities, such as dyslexia and dyscalculia.

What Gillberg suggests is that many of these conditions may exhibit similar and overlapping symptoms early on such that when a child is 3-5 years of age, it might not be possible to predict the diagnostic outcome, only that the individual will likely develop symptoms of any number of these inter-related conditions. For instance, a child at age 3 may exhibit symptoms of specific language impairment, but by adolescence and adulthood present as full-fledged ADHD inattentive type with combined Generalized Anxiety Disorder. Or consider the child at age 4 who fulfills the criteria for autism yet by adolescence may lose the label yet attain diagnoses of OCD, Tourette’s, and ADHD. The point being that the semantic divisions we’ve created in order to diagnose, treat, and better understand these conditions may not accurately reflect the hodge podge of traits that typically occurs in real life across individuals and across a single lifetime.

The idea that these may often be divergent yet overlapping phenotypes, each sharing a similar theme, is appealing considering the extensive genetic overlap scientists are noting amongst these “separate” conditions. If genetic and environmental risk factors are similar, maybe that’s a good indication that what we’re looking at aren’t actually individual “disorders” but different faces to a single die. That doesn’t mean that they share identical etiologies; in fact, the greatest divergence in “cause” may lie at the molecular level (more on this later). However, different effects may funnel into just a handful of phenotypes, and these are the neurodevelopmental conditions with which we’re so familiar today.

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4 responses to “The Essence of Christopher Gillberg’s E.S.S.E.N.C.E. Theory

  1. Gillberg just published his fascinating study on co-existing conditions seen in people diagnosed with an ASD:

    Here is another study that may interest you that doesn’t quite fit the UK and US ‘autism’ is the most heritable of developmental disorders’ claim promulgated by child psychiatrists and molecular geneticists. Genetic influences do operate in Hansen’s disease (Leprosy). Like autism, leprosy is multifactorial involving genetic influences (susceptibility risk factors) but is always only caused by exposure to the mycobacterium leprae pathogen. A study of families in a small island with a high leprosy infected population was published. A small study but eye-opening findings were reported. They calculated a heritability estimate of 57% similar to many autism twin studies. The recurrence risk for siblings under 21 was 6.4%, similar to the autism recurrence risk seen in some Scandinavian sibling recurrence risk estimates. You won’t find anyone who might claim that leprosy is the most heritable infectious disease. Is it time to drop ‘heritability’ from the autism scientific jargon promoted by child psychiatrists and molecular geneticists?

  2. That’s extremely interesting, Robert. And eerily similar. I’ll definitely have to read through both of those articles. Great find especially on the leprosy one; will definitely be pouring through that one. 🙂

    By the way, given your background, you should consider writing a post for SoaC.

  3. One of the autism research study initiatives that also bother me is the recurrance risk for siblings. All of the recurrance risk studies in the UK and in the US (baby sibs) are clinic based studies based on voluntary participation. Clinic based volunteer research studies are not epidemiological studies. They are subject to inflating sib recurrance risk mostly via the well documented bias of ascertainment factor. There is only one population based sib recurrance risk study based on 1.5 million cases residing in the Danish health registries. The sib recurrance rate was 6.9% eerily similar to the leprosy study (6.4%) which is also a population based study.

    • Very good point. Will look over the Danish study. I have to say that the Danes have done an excellent job in regards to some of their large scale epidemiology studies. I’ve used one in my work recently regarding co-occurrence of schizophrenia and epilepsy.

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