Science is certainly far from infallible. That’s especially true of studies related to human beings, on whom any sort of research is notoriously difficult to perform and evaluate. The variables are myriad and uncontrollable, and ethics ordinarily prevents the sort of callous manipulation of subjects that would yield somewhat better results.
When evaluating a disease or syndrome, it helps if the vector of disease is singly determined. This is rarer than one thinks; even in diseases caused by microbes, for example, in which exposure to the microbe is a necessary cause of the illness, it is rarely a sufficient cause. There’s the poorly-understood problem of resistance—why do some people come down with the disease when exposed and others do not?
And even many problems that seem to have a strong genetic component (schizophrenia comes to mind) commonly have only about 50% concordance in identical twins, which indicates that some unknown environmental factor or factors must account for half the variance.
The scientific method was a triumph of human thought, but it took a while to develop because certain things about it are counterintuitive. It requires that we suspend judgment on the causes of a phenomenon even though we may think we can come to conclusions about it on the evidence of our eyes. But often the results run counter to what we would have predicted based on observations and/or intuition. And sometimes, of course, research yields incorrect or ambiguous results because of methodological or observational problems.
And so we come to the case of the autism epidemic. Statistics indicate that the incidence of autism has increased dramatically in the last twenty years or so, most particularly since the early 1990s. Autism is a complex syndrome of disordered childhood development marked by a variety of delays and oddities, a plethora of subcategories, an unknown etiology, lack of a cure, disagreement on the best treatments, and a decades-long history (reversed only recently and imperfectly) of blaming the parents.
It doesn’t take much imagination to see how this particular set of circumstances would lead not only to frustration for parents and professionals alike, but to a tremendous drive to explain what’s happening and what to do about it. But typical of research with human subjects, studies of autism have a long way to go before reaching that particular goal.
Patients and their families have access to a great deal more information these days than previously. Medicine was once limited in most cases to giving comfort and offering a prediction as to the course of the illness; no one knew a whole lot. Then, as knowledge advanced and treatment improved, the doctor became a sort of oracle proclaiming from on high about a source of extremely esoteric knowledge. The patient needed to follow and not to question.
In recent decades this has changed. Patients’ rights have become greater, and access to information has been revolutionized by the internet. Some patients may be so overwhelmed by the choices and responsibilities facing them that they wish their doctors would tell them exactly what to do more often. But most people seem pleased with their new power and knowledge.
I’m in favor of this greater knowledge on the part of patients. But I’m also aware that evaluating medical research is difficult enough for professionals, and can be especially difficult for lay people. It’s not that it requires such enormous intelligence, but it usually requires an understanding of research methods and statistics—and their pitfalls—that ordinarily only comes with a certain amount of specialized training.
For example, in order to get my undergraduate degree in psychology from a university that specialized in research rather than clinical work I had to take a course in statistics and several in research methods. I also had to design and perform a small research project of my own. Then, at the Master’s level, it happened again: a much more complicated course in statistics, one in research ethics, another in evaluating research, and then the design of a far more rigorous study (this one didn’t have to be performed, but it had to be planned in such detail that it could have been).
Even then, I’m no expert on the subject. But all that background gave me more ability to analyze research involving human subjects than I would otherwise have possessed, and more knowledge on the subject than the average person.
There is no question that there is an autism epidemic if one studies the figures. But there’s also no question that diagnosis of the syndrome has changed utterly from what it used to be. “Autism” is now a very big tent. Not only that, but services have expanded exponentially since the early 90s, providing further impetus for the diagnosis of those who formerly would not have received the label, in order for them to be eligible for the benefits they need.
An indication of how difficult it is (and how misleading it can be) to try to compare pre-1990′s statistics to current ones is the change in how statistics are compiled:
In 1990, Congress added the word “autism” as a separate disability category to a federal law that guarantees special education services, and Education Department regulations have included a separate definition of autism since 1992. Before that, children with autism were counted under other disabling conditions, such as mental retardation, said Jim Bradshaw, an education department spokesman.
And yes, just as one might expect, as autism diagnoses have risen, mental retardation diagnoses have declined.
Parents faced with the difficulty of wading through the stress and confusion of labels, treatments, and prognoses naturally turn to other parents, support groups, and the internet and other reading matter. This represents progress, too; in earlier times, parents were very much alone with their sorrows and their challenges (see Clara Claiborne Park’s remarkable book The Seige for a description of what this used to be like, written by the mother of a profoundly autistic child during the 1960s).
Many parents of autistic children are understandably frustrated not only by the difficulties of dealing with their troubled children, but by epidemiologists who question even the existence of the epidemic. How could it not be real? Anyone with a brain can see the profound increase in incidence. What’s wrong with these doctors, anyway?
As commenter TalkinKamel, parent of a child diagnosed with autism, has written in a comment here:
Unfortunately, whether or not there is a real epidemic (I incline towards this view), or whether it’s simply something else, or even just increased diagnosis—-all three of these are depressing prospects.
If there is an epidemic of autism, or something very like autism, then what is causing it, and can anything be done about it?
If it’s an increase in diagnosis, this raises troubling questions about the medical industry’s competence: are, say, educable mentally retarded kids being thrown in with the truly autistic, because it’s just easier to lump them all in together?…Either way it’s troubling, and I’m afraid I have little faith in the experts being able to sort it out, or come up with a solution.
My response is that the entire world of autism is troubling, and although it’s natural to wish for solutions it’s more realistic to expect them to come only slowly and laboriously. It does make a difference, however, in the long struggle towards more effective treatment and even prevention, to know what is actually happening—real epidemic or statistical artifact?—so that precious time, money, and energy is not wasted in efforts directed at the wrong target.
Vaccines are a common focus of concern. As I wrote in Part I, their very success in eradicating (at least for the time being) the diseases they were designed to combat has made their use seem arbitrary, unnecessary, and dispensable, and has made the small but real risks inherent in receiving them seem less bearable. It happens to also be the case that the MMR vaccine is commonly administered at around the time in emotional and cognitive development that many children who are autistic begin to show the signs of their illness. That leads to many reports that a decline began or was noticed after vaccination, and this leads to the understandable conclusion that the vaccine was responsible.
Correlation, of course, is not causation; that’s one of the hallmarks of the scientific method. Nor is simultaneity. Both can be coincidences, or the result of other causes occurring at the same time. But to tease out the truth is not an easy task.
I am not going to present all the pros and cons of the research involved; that would require a book. But I will say that, having read a good deal of it, I come down fairly strongly at this point on the side of thinking the epidemic is almost entirely an artifact of statistics and diagnostic changes. In this I am helped by the fact that most epidemiologists—the experts most likely to be able to come to conclusions on this topic—agree (and the just-linked NY Times article is one of the best summaries on the topic, for those who would like to do some reading on their own.)
The problem of better diagnosis vs. actual increase in incidence is hardly limited to autism, by the way, although autism is an especially good example of the dilemma.
Another excellent article summarizes the issues in the autism epidemic controversy, stating:
Tellingly, around three-quarters of all diagnoses of autism today are for Asperger’s and PDD-NOS, both of which are much less severe than the autism of old….[T]here are other reasons to believe that autism is simply being diagnosed more often now than in the past. One is the “Rain Man effect” – the huge increase in the public awareness of autism following the 1988 film starring Dustin Hoffman. Awareness has also increased massively among healthcare workers….Another factor is that one of the stigmas of autism has largely disappeared….Finally, while some parents still have to fight for help for their autistic children, far more services are now available. This has encouraged doctors to label borderline or ambiguous cases as autism…
[A]n epidemiological study carried out in the 1980s simply cannot be compared with one done last week. There will be so many differences in diagnostic procedures and in the willingness of doctors and parents to label a child autistic that comparisons are meaningless….
As an example of the type of data that leads people to believe the epidemic is real, and the sort of research required to tease out whether this might be true or not, the article offers the following study, among others:
Perhaps the strongest case against the “better diagnosis” theory is that, if true, there should be a “hidden hoard” of autistic adults who were never properly diagnosed in childhood. To parent Richard Miles, this is compelling. “My doctor cannot believe that he could have missed so many cases in the past,” he says. But Taylor disagrees. As a former general practitioner, he says there are many children today diagnosed with autism who would not have been labelled as such in the past.
This view is difficult to substantiate, but in 2001 a team led by Helen Heussler of Nottingham University, UK, had a crack. They re-examined the data from a 1970 survey of 13,135 British children. The original survey found just five autistic children, but using modern diagnostic criteria Heussler’s team found a hidden hoard of 56. That’s over a tenfold rise in numbers, which puts the California figures in perspective. Heussler and her colleagues concluded that “estimates from the early 1970s may have seriously underestimated the prevalence”.
And then there’s this, concerning the vaccine connection:
A recent study from Japan may prove the final nail in the coffin for the MMR theory. It found that diagnosed cases in that country continued to rise even after the triple jab was withdrawn.
Science is no panacea, although we might want it to be. Medicine doesn’t usually progress by leaps and bounds. More often it limps along, or meanders, or moves in fits and starts. But the general course is in the direction of greater knowledge, slow though the accretion of that knowledge may be, desperate though the desire for more immediate answers.
In the meantime, we must be very careful not to expect too much of science—and, in our frustration with it, trust too much in hypotheses and explanations that don’t hold up under scrutiny. The irony is that, imperfect though science is, it is still the best tool we have right now for finding the answers we seek.