Sensory processing disorder is one of those peculiarly modern diseases caught in the purgatory between legitimacy and quackery. It’s widely accepted that some children have difficulty handling external stimuli. Kids diagnosed with autism and ADHD have trouble managing sensory experiences that others deal with easily. They cover their ears on the playground, for example, or complain that their clothing is intolerably scratchy. That much is uncontroversial. In the 1970s, however, a UCLA psychologist claimed that sensory processing failure is not merely a symptom of other disorders but is more often a freestanding disease with its own neurologic basis. After 40 years of debate, we still don’t know whether she was right.
This debate sounds like a medical technicality, but the distinction between symptom and disorder matters a great deal. It matters because tens of thousands of parents are convinced that their children’s behavioral issues are the result of sensory processing difficulties. They don’t believe, or can’t believe, that the real problem is anxiety, ADHD, or autism. It also matters because barrel-loads of money are on the line. Advocates claim that up to 16 percent of American children suffer from SPD, but few insurance companies will pay for therapy until mainstream doctors are convinced that the disease is real and treatment works.
Official recognition seems distant, however, because the good ship SPD has come upon choppy seas of late. Two years ago, the American Academy of Pediatrics issued a position paper concluding that there was insufficient evidence that sensory processing challenges represent an independent disorder. The organization warned pediatricians against diagnosing children with the disease and advised parents that there is limited evidence to support existing therapies. SPD experienced a more significant setback in 2013, when the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders excluded the disease on the basis of inadequate evidence.
The series of rejections has set up a pitched battle between the medical “establishment” (if that term can be used non-pejoratively) and angry families. The current standoff is a good example of why the Internet is a terrible medium for debating medical issues. The stakes are highest, and the need for a resolution most urgent, for the people who are least able to understand the science. That’s not a dig at families who are struggling with major behavioral problems—it’s simply a fact of modern life and scientific practice. Doctors need time and money to untangle complicated psychiatric issues.
A brief look at the literature reveals why these issues are impossible for laypeople to adjudicate. There are dozens of papers addressing the disorder in peer-reviewed journals. Quality and quantity are not the same thing, though. Even Lucy Miller, director of the Sensory Therapies and Research Center and one of the leading advocates for SPD, acknowledges that the early research was “not rigorous.” Those shortcomings put advocates in a hole, as major journals and many medical experts came to think of SPD research as unscientific.
SPD research has unquestionably improved in recent years. Advocates have better outlined categories of sensory processing problems, improving the framework for research. The National Institutes of Health have funded some of the research, granting it no small degree of legitimacy. Last year, a paper in the journal Neuroimage: Clinical purported to identify structural brain abnormalities in children with clinical evidence of sensory processing issues.
Many hopeful parents think that means victory, but it’s not even close. Despite 40 years of discussion, SPD researchers have yet to agree on a proven, standardized diagnostic tool. This undermines researchers’ ability to define the boundaries of the disease. It makes correlation studies, like the one about structural brain abnormalities, less convincing. It also makes it impossible to test the effectiveness of the therapies, many of which, to be frank, look a little loopy to stuffy scientific types. (Spinning? Swinging?) If you can’t prove that the therapies work, insurance companies are not going to pay for them.
Larry Desch, a pediatrician and co-author of the 2012 report that declined to recognize SPD, acknowledges that some of the recent research, which uses a blinded approach to distinguish between SPD and other disorders, is of a high quality. But, he muses, “Has there been enough clear data to determine that what we are seeing in some children is truly a disorder and not just a temporary issue or a variation of normal?” That question will take many more years to answer.
There have also been some public relations setbacks for SPD. In 2007, New York Times science writer Benedict Carey described sensory processing disorder as belonging to “the special-needs vernacular,” which also included attention deficit hyperactivity disorder. It’s not clear whether Carey intended to be critical, but it’s bad press for a childhood psychiatric disorder to appear in a sentence with ADHD, the stand-in for our national preoccupation with over-medicalizing childhood behavioral problems.
Backers of the disorder also haven’t helped themselves. The checklist of symptoms on the website of the SPD Foundation, one of the primary advocacy groups for the disorder, is almost impossibly broad. It includes such warning signs as “My infant/toddler has problems eating,” “My child has difficulty being toilet trained,” “My child is in constant motion,” and “My child gets in everyone else's space and/or touches everything around him.” These read more like the day-to-day complaints of an average parent than a symptom screen for a legitimate psychiatric disorder. The estimate that 16 percent of children suffer from SPD also seems hard to accept, contributing to the perception among skeptics that the SPD diagnosis stigmatizes children who are simply sensitive to noise or poorly behaved.
Desch uses the word waiting when describing the state of play. Pediatricians and psychologists are waiting for more studies, waiting for a standardized diagnostic tool, waiting to learn whether the therapies heal behavioral issues better than the passage of time alone. Thousands of concerned parents are waiting, too.
It’s difficult to predict where SPD will go from here. It could become the next fibromyalgia, a once-mocked diagnosis that has achieved general—if begrudging—acceptance. Or it could go the way of chronic lyme, a would-be disease that saw its proponents’ hopes for official recognition effectively ended in a comprehensive debunking by the Infectious Diseases Society of America in 2006. Even so, chronic lyme advocates continue to accuse physicians of colluding with insurance companies to deny them needed coverage.
There have already been similar rumblings among devotees of sensory processing disorder. “Probably paid off by the insurance companies,” grumbled one commenter beneath a story about the 2012 report.
Don’t join these conspiracy theorists. There’s no evidence of corruption, bias, or incompetence on either side. Give the professionals time to do their work. You may know your child, but they know the science.