Plain Talk about PDD and the Diagnosis of Autism
Written by Bernard Rimland, Ph.D.
Autism Research Institute
4182 Adams Avenue
San Diego, CA 92116
Let's start with the obvious: the label PDD (Pervasive Developmental
Disorder) is a poorly understood, uninformative, confusing, disliked,
and should be abandoned. The sooner the better. In fact, it should
never have been adopted in the first place.
Over the years I have talked and corresponded with thousands of
parents who have told me their child "has PDD." I often
respond by saying something like, "Your child doesn't have PDD. There is no such thing as PDD. Your child may be autistic,
or have a condition like autism, or many characteristics of autism,
but he doesn't have PDD because there is no such thing. PDD is
a label concocted by psychiatrists to cover up the fact that they
don't know what your child does have."
If any parents have been distressed by this blunt, unexpected
harangue on my part, I would be surprised. The vast majority seem
relieved to at last hear someone giving them straight talk about
PDD. Parents live with their child 24 hours a day, 7 days a week.
These parents realize that their handicapped child will in all
likelihood be the central focus of their lives for the rest of
their lives. They want to know the truth, insofar as the truth
is known. They don't want to be misled or misinformed by sugar-coated
verbiage masquerading as informed fact. If we don't know the right
label for their child, let's tell them that up front, rather than
hide our ignorance behind the mystique of a pseudo-scientific
label, presuming knowledge we don't have, like PDD.
I am very much aware that creating suitable names for "psychiatric"
or "behavioral" disorders is a difficult and thankless
task. Look at what we have now: Schizophrenia is Greek for "split
mind." Mental retardation is a euphemism for low intelligence.
Hyperactivity merely describes what everyone knows too well--the
person is too active. Autistic means "day dreaming."
Until we know what causes these things we are stuck with using
a somewhat descriptive term to characterize them. I'll agree to
that, as a matter of necessity, but where does PDD come in?
The passage of time has led to widespread usage of the terms,
schizophrenia, mental retardation and autism. There is little
or no likelihood that PDD will be afforded similar acceptance.
In the Autism Research Review International (ARRI) (1991,
Vol. 5, No. 2), we summarized an excellent statement, signed by
16 prominent European and U.S. professionals in the field of autism,
titled "Autism is not necessarily a pervasive developmental
disorder." The authors noted that although the term PDD was
introduced well over a decade ago, it has not really caught on,
and is unfamiliar not only to lay people, but to the politicians
and administrators, most of whom--thanks probably to Rain Man--are
aware of autism. The article observes that the term "pervasive"
is particularly inappropriate, since severely retarded persons,
many of whom have chromosomal defects which affect every cell
in their bodies. Autism, they point out, rather than being a pervasive disorder, is in fact a specific one, characterized by deficits
in social and cognitive functioning.
Quite apart from the misleading and inappropriate semantics of
the term PDD is a practical matter: autistic children and adults
unfortunate enough to have the PDD affixed to them have often
been--and continue to be--excluded from programs and services
designated for those with autism, and which would benefit them.
Clearly, the PDD designation, along with its cumbersome bureaucratic
baggage (i.e., PDD-NOS: "Not Otherwise Specified") should
be relegated to the Archives of Failed Attempts, where it will
have plenty of company, while we go on about our business.
There are many more children with autistic-like disorders than
there are children with autism itself. When I founded the Autism
Society of America in 1965, I urged, and my recommendation was
followed for many years, that all ASA stationery, brochures, and
other printed materials carry the wording "Dedicated to the
welfare of all children (later 'children and adults') with severe
disorders of communication and behavior." The need for an
encompassing title for this group was evident even then.
Of the various labels that have been suggested, the one I like
best is "autistic spectrum disorder," which, I believe,
was first suggested by Wing and Gould in 1979. The advantages
of this term are obvious. For one, it acknowledges that there
is a range of problems and of subtypes, and it does not pretentiously
claim to be based on knowledge that is not yet available to us.
At the Autism Research Institute we have been working for over
a quarter of a century on the development of more objective scientific
means of diagnosing children with autism and related disorders.
When my book Infantile Autism was published in 1964, it
contained, as an appendix, a checklist designated "Form E-1"
(E for experimental). Within a year E-1 was replaced by the Form
E-2. As of June 1993, the Autism Research Institute has collected
over 16,800 E-2 forms, completed by parents of autistic and possibly-autistic
children in over 50 countries. (Form E-2 is available in eight
languages.)
Form E-2 is designed for completion by the child's parents, and
asks questions about the child's early development and about language
and behavior through age five an a half. (After age five an a
half, autistic children begin to change in many ways, so it is
better to rely on behavior prior to that age.) Once we receive
a completed E-2 form from a parent or professional, we enter the
data into our computer, derive a score which tells the child's
position to the continuum ranging from "classical autistic"
at one end to "not autistic" on the other, and mail
a report to the sender. We have performed this service, free of
charge, for well over a quarter of a century for thousands of
parents and professionals world-wide. (Readers of the ARRI are invited to request E-2 forms and avail themselves of this
free service.)
A major purpose of this effort is to collect data for statistical
analysis. There is no doubt that the "spectrum of autistic
disorders" contains numerous subtypes, some of which are
large enough to be identified by as our database of almost 17,000
E-2 Forms. We are already aware of some of these types, such as
classical--Kanner's Syndrome--autism, fragile X autism, Rett syndrome,
and candida-caused autism. My colleague, Dr. Stephen Edelson and
I are conducting factor analyses and cluster analyses of the E-2
database, in order to identify and characterize these and other
subtypes. The database is large enough so that subtypes identified
by cluster analysis within one segment of the database can be
confirmed by cross-validation on E-2 data which was not used in
the original identification of subtypes.
As this work advances we will report on progress in the ARRI,
and in other places. Subtypes identified through this means of
statistical analysis can be validated in a number of ways, independent
of the E-2 database, including family history variables, clinical
laboratory tests, and differential responses to drugs and other
treatments. It is thus hoped to place the diagnosis--as well as
the treatment--of "autistic" children and adults on
a more scientific basis. I believe that progress in this field
will proceed faster if we rely on the identification of subgroups
through the analysis of statistical data, rather than on constructs
based on speculation, conjecture, surmise and subjective impressions.
In the meantime, let's get rid of "PDD!"