Ask the Experts: David Evans on spectrum disorders
November 11, 2010
LEWISBURG, Pa. — Professor of Psychology David Evans, a developmental neuropsychologist, talks about repetitive, ritualistic behavior in children and the interplay between normal development and pathological behavior.
Q: You study the relationship between so-called normal behavior and ritualistic and repetitive behavior such as obsessive-compulsive disorder. Can you explain more about this relationship?
A: There is an often-cited quote by psychologist Dante Cicchetti, who is a professor at the Institute of Child Development at the University of Minnesota. He said, "We can learn more about the normal functioning of an organism by studying its pathology, and likewise more about its pathology by studying the normal condition."
Traditionally, in psychology and psychiatry, it was thought that the studies of normality and pathology could not inform each other so the idea that someone with a mental illness could be understood by understanding normal processes was pretty radical. I believe in order to study what is abnormal, you need to know what's normal.
Some of the early work that drew parallels between normal and atypical development was conducted by one of my mentors at Yale University — Edward Zigler, who was a major figure in research on mental retardation (now referred to as intellectual disabilities). Ed was one of the first people to suggest that children with mental retardation take essentially the same path in their development as do their typically developing age-mates; they just go through development more slowly. There are essential similarities between children who might be considered "abnormal" and typically developing children. This places typically and atypically developing children on a spectrum, rather than viewing them as qualitatively different from each other. So by studying one group we are studying the other.
Q:How does your research approach help us learn more about neuropsychiatric disorders?
A: My specific interests involve the development of repetitive behavior. I draw parallels between the normal development of repetitive behavior and the kinds of repetitive behavior that appear in disorders like obsessive-compulsive disorder, Tourette's syndrome and autism spectrum disorders.
On the face of it, these disorders may appear to have little in common with normal development. With OCD for example, people feel compelled to engage in repetitive behavior like hand-washing or ordering and arranging, and the behaviors make them confused and upset. Tic disorders like Tourette's syndrome are different from obsessive-compulsive disorder, but they still involve strange habits and uncontrollable movements. And children with autism spectrum disorders have strong preferences for sameness in their everyday routines and are often sensitive to minute changes in the environment.
But, interestingly, typically developing children also experience similar behaviors, albeit maybe less severe. For example many two-, three- or four-year-old children "need" to engage in a bedtime ritual or routine; they have strong preferences for certain foods and certain articles of clothing. They might even go through a period of body rocking, or head rolling — behaviors that resemble some aspects of autism.
My work examines the parallels between normally developing rituals and habits, anxieties, fears and phobia, and how they relate to normal cognitive and brain development. So far it seems that there are many parallels — much more than previously thought.
Q: Awareness of autism and spectrum disorders seems to have increased in recent years. Has there also been an increase in diagnoses of these cases?
A: It's indisputable that there's an increase in diagnoses of autism spectrum disorders. The issue is why? Autism was first described in 1943 by Leo Kanner, a psychiatrist. He wrote the first paper on it that identified 11 children who had what we would now call autism. He took the disease entity approach, though. That is, either you have autism or you do not, and the symptoms he identified were restricted or repetitive behaviors, severe social impairment and language delay. In fact, historically about 75 percent of kids diagnosed with autism had no language at all. So the early definition of autism was probably what we would think of now as being pretty severe and limiting, and autism was considered quite rare.
During the past 20 years, the concept of the autism spectrum has come into the fore of our culture. With the introduction of the concept of spectrum approach to disorders like autism, we look at things on a continuum. So a child who is a little bit socially awkward, who's got some kind of peculiar interests, we would say is "on the autism spectrum." Thirty years ago, we might have said that same child was kind of geeky or odd, but there would have been no diagnosis of autism.
What's happened is that there has been a kind of heightened cultural awareness of themore subtle variants of these kinds of behaviors. Parents more and more are saying, "Something may be wrong. We need and want a diagnosis so my child can get the clinical and educational attention he or she needs." This may lead to over-diagnosis.
Q: What are some of the reasons for increased or over-diagnosis?
A: Increases in diagnoses of autism are likely due to increased awareness of the signs of autism, parental willingness to look for a diagnosis, and a loosening of the criteria on the part of clinicians to diagnose more subtle versions of what may or may not be autism.
Part of the growth in diagnoses — not just of autism but a number of other clinical conditions as well — has been engendered by a growing appreciation for the importance of early intervention. So we want to identify problems as early as possible. By definition, autism has to emerge by age 3. But because it involves things like social development and language development, you are obviously not going to see many of the symptoms until language and social development start to emerge.
All of these facts converging have created a cocktail for a movement that has resulted in what seems like an explosion of autism spectrum disorders in the effort to identify the earliest signs and symptoms — some of which may be part of normal development.
Our understanding of what constitutes normal language development has far outstripped our understanding of what is normal in terms of other aspects of disorders like autism — repetitive behavior, for example. We don't really know what the standards for normal rituals, habits, routines, or even behaviors like head-banging or self-injury are. There is some risk therefore that we may be taking a child and diagnosing him or her when what we are seeing is normal variation in behavior.
Q: In recent years, there has been a lot of talk about whether vaccines cause autism. Do they?
Many studies have been conducted testing the "vaccination" hypothesis, and the evidence is clear: vaccinations do not cause autism. The agent that is used to bind multiple vaccines together —Thiomersol — was removed from the vaccinations administered to large populations of children, and the diagnosis of autism spectrum disorders continued to increase.
Something else is responsible for increases in the prevalence of the disorder, and this "something else" is likely is that there have been changes in the ways that diagnoses are being made and an increased awareness of the disorder.
Q: There has been an emergence recently of reality television shows examining the phenomenon of hoarding. What is hoarding and is it a good thing to draw attention to?
A: Hoarding is one manifestation of obsessive-compulsive disorder, and it is not a new disorder. The fascinating thing about hoarding as a form of OCD is that one person can be an animal hoarder; one can hoard meaningless scraps of paper, pieces of string, newspapers, you name it. These are not people who have normal collections, and yet we know very little about what they do (or do not) have in common with "normal" collections.
The American Psychiatric Association publishes a book called the Diagnostic and Statistical Manual of Disorders (DSM), which is the guideline for clinical psychiatrists to diagnose mental illnesses. In order to have OCD, the DSM says you have to have two things: obsessions and compulsions. Whether a given behavior is clinically significant depends less on what the behavior is, and more on the degree to which it interferes with your life.
I consider OCD to be a hidden epidemic in that I think it's everywhere, and everyone's got some of it. In fact, I believe that some OC-tendencies may have had some evolutionary advantage in that they favored traits that keep us ordered, organized, clean and free from germs. But in OCD these normal adaptive tendencies have run amok.
I think anything that brings public awareness such that people may feel more comfortable identifying that they might have a problem or that someone they know has a problem, is good.
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