In defense of childhood disintegrative disorder
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Diagnostic pattern: Children with Childhood Disintegrative Disorder have severe loss of skills after 2 years of age, leading to symptoms of autism such as repetitive behaviors.
Regression, or the loss of skills, has been associated with autism since Leopold Kanner first used the word ‘autistic’ to describe a group of children with abnormal sociability and repetitive patterns of behavior in 19431. Kanner described one of his patients as having “gone backward mentally” for two years. Today, any of the five autism spectrum disorders, as listed in the Diagnostic and Statistical Manual of Mental Disorders IV, Text Revised (DSM-IV-TR), may be associated with regression. But one in particular, childhood disintegrative disorder, is defined by it.
A diagnosis of childhood disintegrative disorder requires that a typically developing child over 2 years of age undergo a severe and mostly irreversible regression of developmental gains, including speech, sociability and self-help skills. Theodor Heller first described the disorder as dementia infantilis in 19082. Despite significant changes in classification systems since 1908, the clinical features Heller described remain the backbone of today’s definition of childhood disintegrative disorder, which was introduced in the DSM-IV in 1994.
But there is controversy in the autism field about whether childhood disintegrative disorder really is a distinct entity, worthy of its own diagnostic category.
In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), due to be published in 2013 and now in draft form, childhood disintegrative disorder will be subsumed into a larger autism spectrum disorders category. The committee responsible for drafting the new criteria writes, “We believe that children meeting the DSM-IV-TR criterion [sic] for childhood disintegrative disorder will now fit well within the new diagnostic criteria for autism spectrum disorders.” The committee explains this further when discussing changes to the autism spectrum disorders criteria in general: “previously, the criteria were equivalent to trying to ‘cleave meatloaf at the joints.’”
Perhaps the existing diagnostic utensils are akin to gilded spoons, able to scoop out a serving of meatloaf but incapable of the precise cuts necessary to address empirical questions. But we believe that the late-onset, well-defined regression found in childhood disintegrative disorder is an example of a well-differentiated phenomenon. Any muddiness about the diagnosis is related to the diagnostic tools rather than the disorder itself.
We believe that childhood disintegrative disorder represents a process sufficient to cause autism, but that it is different from the mechanism that leads to autism in children without regression. As such, it is an important example of the heterogeneity of the autism spectrum. Doing away with a separate diagnosis of childhood disintegrative disorder would hinder research efforts into better understanding autism.
Distinct development:
As the DSM-5 committee recognizes, it has been unclear whether individuals with childhood disintegrative disorder have a late-onset or regressive form of autism, or whether this diagnostic category captures a truly distinct condition that affects certain children.
To examine this, Fred Volkmar and Donald Cohen compared a group of children with childhood disintegrative disorder, diagnosed using the International Classification of Diseases-10 criteria, to a group of children who were diagnosed with autism after 2 years of age3. They found that the children with childhood disintegrative disorder had accumulated more skills than the children with autism prior to regression and had worse speech and intellectual disabilities subsequent to it.
From this, they concluded that childhood disintegrative disorder merits a separate diagnosis from late-onset autism. Subsequent studies supported these findings4,5,6. However, there are also children older than 2 years of age who gradually regress, and the rare children younger than 2 years who experience rapid and dramatic regressions like those that occur in childhood disintegrative disorder7.
Other clinical evidence also supports the distinction between childhood disintegrative disorder and late-onset or regressive autistic disorder. Childhood disintegrative disorder is accompanied by deterioration across multiple domains8, whereas in autistic disorder, regression is often isolated to language. The onset of childhood disintegrative disorder is rapid in comparison to autistic disorder, which is insidious3. Children with childhood disintegrative disorder have seizure disorders and encephalography, or EEG, abnormalities more frequently, and also have higher levels of anxiety and stereotyped patterns of behaviors9,10,11.
The fact that these variables are not directly related to the diagnostic criteria for childhood disintegrative disorder supports the clinical validity of the disorder, by suggesting it has distinguishing characteristics in addition to those criteria.
All in the timing:
Psychologist Cheryl Hendry contends, as does the DSM-5 committee, that the diagnostic continuity between autistic disorder and childhood disintegrative disorder undermines the argument that childhood disintegrative disorder and autism are distinct: “Childhood disintegrative disorder should not yet be considered distinct from [autistic disorder], as not enough information exists to justify it as a separate diagnostic category,” she writes in a review published in 2000. Hendry further argues that the diagnosis is an unwarranted division of a cohesive group, pointing to a fundamental problem with categorical diagnostic systems12.
It is true that to re-conceptualize the autism spectrum disorders along behavioral dimensions, as will happen in the DSM-5, will draw attention to the fact that many of the factors that distinguish childhood disintegrative disorder from autism are differences of degree, rather than kind. These differences of degree might even illustrate the similarities between autism and childhood disintegrative disorder, rather than the differences.
But the unique and dramatic development of the children currently described by childhood disintegrative disorder suggests that there is more to be gained from first recognizing the disorder as a distinct category and then looking at its overlap with other conditions, than from eliminating the diagnosis altogether.
Research conducted by our team at the Yale Child Study Center emphasizes two points relevant to this discussion. First, children with diagnoses of childhood disintegrative disorder undergo severe, rapid regressions. In the group we study, 70 percent have bouts of terror and agitation preceding regression. In our recent translation (in press) of Heller’s 1908 paper, Über Dementia Infantilis, we found multiple references to anxiety, terror, motor agitation and generally bizarre behavior, all preceding the loss of adaptive function.
For example, of one of his subjects he wrote: “In the third year of life the child underwent a psychosis. Attacks of severe [night terrors] occurred several times. Later on he seemed to be nervous during the day as well, he talked gibberish, seemed to be afraid and often didn’t recognize his parents.”
Second, children with childhood disintegrative disorder undergo very substantial losses of adaptive function and end up far more disabled than their counterparts with autism and no regression.
The symptoms that precede regression and the devastating nature of the regression itself may reflect the timing of the process: The later you regress, the more you have to lose, and the more dramatic and severe the regression is. After all, we know that the behavioral changes associated with autism are cumulative. For example, cognitive researchers Warren Jones and Ami Klin observe that “failure to look at the eyes of others during critical windows of development, and looking at other parts of the world instead, suggests an altered path for learning about the world, with cascading effects on further socialization13.”
An explanation for childhood disintegrative disorder that depends on an altered path for learning about the world and the cascading effects that this has on subsequent development is not easy to reconcile with its precipitous onset. It seems likely that although childhood disintegrative disorder and autism are, eventually, clinically similar, the natural history of childhood disintegrative disorder marks a unique mechanism, the elucidation of which could inform us about autism in general.
Because of this possibility, childhood disintegrative disorder deserves a high degree of research scrutiny. Without a distinct diagnostic category, clinicians would be less likely to bring unusual, late-regressing children to the attention of researchers. The science will suffer as a result.
From this point of view, not enough information exists to take the risk of eliminating childhood disintegrative disorder as a separate category in the DSM-5. We hope that a more complete understanding of the biological basis of childhood disintegrative disorder will eventually lead to its removal from the DSM-5, as with Rett syndrome, but removing the disorder now will hinder efforts to discover the pathophysiology of this unique and devastating neurodevelopmental disorder.
Kevin Pelphrey is Harris associate professor in the Yale Child Study Center. Alexander Westphal is a clinical fellow in the department of law and psychiatry at Yale University.
References:
1: Heller T. Zeitschrift für die Erforschung und Behandlung des Jugendlichen Schwachsinns 2, 17-28 (1908)
2: Kanner L. Nervous Child 2, 217-250 (1943)
3: Volkmar F.R. and D.J. Cohen J. Child Psychol. Psychiatry 30, 717-724 (1989) PubMed
4: Siperstein R. and F. Volkmar. J. Autism Dev. Disord. 34, 731-734 (2004) PubMed
5: Malhotra S. and N. Gupta Eur. Child Adolesc. Psychiatry 11, 108-114 (2002) PubMed
6: Volkmar F.R. et al. Am. J. Psychiatry 151, 1361-1367 (1994) PubMed
7: Volkmar F.R. and M. Rutter J. Am. Acad. Child Adolesc. Psychiatry 34, 1092-1095 (1995) PubMed
8: Wohlgemuth D. et al. (1994). Childhood disintegrative disorder: Diagnosis and phenomenology. Paper presented at the American Academy of Child and Adolescent Psychiatry: Annual Meeting, New York.
9: Kurita H. et al. J. Autism Dev. Disord. 22, 175-188 (1992) PubMed
10: Mouridsen S.E. et al. Psychiatry Clin. Neurosci. 54, 441-446 (2000) PubMed
11: Rogers S.J. Ment. Retard. Dev. Disabil. Res. Rev. 10, 139-143 (2004) PubMed
12: Hendry, C.N. Clin. Psychol. Rev. 20, 77-90 (2000) PubMed
13: Jones W. and A. Klin J. Am. Acad. Child Adolesc. Psychiatry 48, 471-473 (2009) PubMed
Comments
It is interesting that as in autism, in CDD the researchers are looking at the cognitive and social impairments first, when they are so obvious and leave no other interesting pathway to do research.
Why aren't they looking at the autonomic systems in relation to the immune and endocrine systems of these children?
Every blurb out there on these CDD problem reports that they loose their bowel and bladder control and that they have enormous difficulties transitioning from sleep to awaken states. These two problems which occur with a sudden onset according to what is reported out there should be sufficient to cue people to look into these more 'primitive' vital systems. But instead they continue to describe the obvious: cognitive and social impairments -and argue forever about the discrepancies that no subjective inventory could ever resolve.
These cognitive and social impairments are the byproducts of something more fundamental. Cognitive and social skills of the kinds that they lose (in CDD) or fail to acquire (in autism -whatever that is) are late acquisitions in the evolution of humans. The autonomic and automatic systems controlling the brain-body coupling had to be in place way before we could manage to develop language, and abstract thoughts. They had to function with the systems that guaranteed our survival and reproduction.
Why isn't anybody examining the immune and endocrine systems of these children in relation to the autonomic and automatic centers of the brain?
And why aren't any reports out there on gender differences at the clinical level?
I fail to understand the approach to autism and related problems. To outsiders like myself there are basic questions that I would like to have answers for before settling on a definite diagnosis criteria. There is data to answer these fundamental questions already. But even asking them can be problematic for newcomers into the autism phenomena. Too much politics...
Kevin and Alexander
Thanks for a brilliant and informative article. Perhaps there's one thing you could clarify for me.
In the recent paper from the Amaral group, looking at brain size in autism, the authors made a distinction between autism with and without regression. I was surprised to read that roughly half of the kids in their sample were considered to have regressed. And that this was considered to be parr for the course based on previous studies. Admittedly, given that the children necessarily had to be diagnosed very early for inclusion in the study, this is not an entirely representative sample. But it still suggests that some sort of regression is relatively common.
There seem to be two possibilities. Either CDD is very common (certainly far more common than I'd ever appreciated), or there is a distinction between the kind of regression you're talking about here in the context of CDD and the kind of regression that Amaral et al are talking about.
Jon
Nordahl, C., Lange, N., Li, D., Barnett, L., Lee, A., Buonocore, M., Simon, T., Rogers, S., Ozonoff, S., & Amaral, D. (2011). Brain enlargement is associated with regression in preschool-age boys with autism spectrum disorders Proceedings of the National Academy of Sciences, 108 (50), 20195-20200 DOI: 10.1073/pnas.1107560108
I agree with Liz that there are many things to be looked at in CDD and that the immune system, for example, may have an answer. But CDD is so rare that and poorly understood that even the most basic things are important to clarify, and any question that is tackled is better than no tackling at all! With respect to Jon's question, if the distinction between the populations is made on the basis of regression alone, rather than on age at onset, which really is the cleanest way of doing it, then CDD becomes part of a much larger group. On the other hand, there seems to be something so different about children with very substantial periods of typical development who suddenly have catastrophic losses. Be sure that as we study CDD, we will look at people with less dramatic losses, using the same experimental paradigms, to try to sort this out.
Thanks Alexander
As the mother of a child with CDD and having worked with people with autism for over twenty years, I totally agree with your article. It is great to see some research being conducted on this rare disorder. Hopefully, the people who are writing the new DSM will take not.
I have a son (who is a fraternal twin) who was struck with CDD at aprox. the age of 3 and a half. He is now 21 years old. We live in a fairly remote part of northern Canada. I have only been able to connect with one other parent with a child with CDD, and she was in the USA and this happened more than 10 years ago. I would love to become acquainted with other parents or caregivers of individuals with this disorder. Please contact me at therchak@sasktel.net.
Thank you very much!
You have my support in resisting the blanket diagnosis, I also agree that the unique detail of the exceptional case is vital to the wider understanding we need. But hese complexities are in the nature of every individual, the special case is also every unique individual.
I realize also that the 'diagnosis' relates only to symptoms and has little to do with root cause. You naturally seek the root cause or causes. In any complex system there are always multiple causal pathways to the same outcome criteria, and hence here we have (understandably) a converging blanket diagnosis. I see a weakness in your subgroup argument though- because your stated wish to study the isolated subgroup carries the same defect admittedly to a lesser extent- (diagnostic definition). Solving(or understanding) these complex problems may require a different tack (complexity is never knowable). My experience has been that specific detail at the individual level, leads directly to evidence ( say gut fauna)There are treatment programs which take the individual, and treat the whole life symptoms using a range of specific test and diagnosis of his /her systems. With specific treatments normal development has the opportunity to re establish. Without the individual diagnosis of subsystems, and their treatment- autism retains it's confounding presence. This complex model for autism means that current research techniques cannot succeed in say 'finding a cure for all autism'. They will however highlight segments of the causal routes like highways on a road map. Good medicine treats the person, not just the symptom. Those pathways are not yet politically enabled in commercially civilized economies, and indeed such an alternative must challenge the established health management provision.
My 20 year old son has a diagnosis of CDD. I am concerned that the new DSM-5 will subsume this disorder under the broader category of ASDs. This is particularly true since the DSM-5 specifies that signs of the disorder "must be present in early childhood". My son was first diagnosed with PDD-NOS (or HFA) at the age of 11. By age 15, he had regressed to the point that he better met the criteria for autistic disorder. He wasn't diagnosed with CDD until age 17. He DID NOT show signs of autism in early childhood. Where would he fall under this new system?
Wow, Elaine. Maybe Autism, like epilepsy, can come at any time. Your son's case could guide science by it's uniqueness. Have you allowed him to be studied? (I say this as a mom who lived in fear my son would regress from PDD-nos diagnosis at age 3, not a scientist. I mean no disrespect to you or your son.)
I can't find anyone who is interested in studying his case! I know how unique he is. I don't know what else to do.
My son began his regression at about age 2 1/2. Before he regressed, he had hundreds of words, spoke in full sentences, used spontaneous and appropriate language, etc. His gross motor skills were also developmentally appropriate. For Christmas that year (he was 2 1/2 at the time), he got a baseball tee, bat and ball. He loved it, could put the ball on himself, swing and hit the ball all by himself. Just a few months later, he had no idea what to even do with the ball or the bat. He had no clue what the purpose of the entire exercise and could not even swing the bat. He lost almost all of his language. He was diagnosed with autism the month after he turned 3. His speech had dropped dramatically, he was saying fewer and fewer words, mostly mumbling, but he still had real words in there. At the time of diagnosis, the doctor diagnosed him as mildly autistic. I think he was just one point over the threshold on the CARS for an autism diagnosis. She said she thought he would be more of an Aspergers as he got older. Shortly after that appointment, he had lost ALL language, and his fine and gross motor skills went down the tube. We saw a neurologist maybe a month after his diagnosis, and she said he was severely autistic.
I have no doubt there is a distinct difference between children with late, severe regressions and autism.
My son was diagnosed with CDD right before his fourth birthday. At about three and a half, there were some social areas (soccer and gymnastics) that became a little more difficult. Then, we went on a wonderful vacation to Hawaii with two sides of the family and hit two islands. A vacation we couldn't take for literally sixy seconds in this life. We came home and he started to display severe seperation anxiety from me. The questions I usually asked him about shapes and colors seemed more difficult for him. His stories seemed a little different. Then, he was struck and lost most all language. He screamed in the night, and one night clawed my face and yelled "help me." He was able to blurt out sentences once in awhile, but eventually lost that ablity. He'll get a word or forming of a word once in awhile, right now it's "up." It drives my husband crazy, but I remind him if you only had one word how many times a day would you use it. My son's EEG is irregular and he has autoimmune issues that don't fall into a specific catagory. He also has a varying amont of infammation on his brain. We have gone through bladder and bowel control scares and are in one know. I just know there is so much more research to do on kids like my son.
I hated the diagnosis of CDD in the beginning, but later sought comfort that there was something tangible to read (if only tangible in print). I have beautiful videos of him before his onset, but I never had the heart to continue documenting his life; although, it is the strangest journey every imagineable. I am a Marriage and Family Therapist, and I work out of the DSM. I am bothered professionally and personally, because the main tenet of therapy and diagnosis is "Do no harm." Even my daughter, who is two years older than him, does not want to use autism to describe him. She knows her family's journey has been different and deserves a name of it's own. My email is mchaley931@att.net if anyone is interested in connecting.