When I tell parents that I've been writing about autism for 15 years, it doesn't take long to get to the questions. They lean in close and ask, "It's the vaccines, isn't it?" Or, "It's the pesticides, am I right?" Or, "I heard it's the GM foods?" It, that is, being the mysterious X factor responsible for the dramatic rise in autism diagnoses since the early 1990s.
Fundraising organisations in America routinely refer to this increase as an autism 'tsunami', or even an 'epidemic', as if your child could catch it in the playground. Meanwhile, health officials - wary of making blanket statements about hot-button issues before all the facts are in - cautiously attribute the rise to factors such as broadened diagnostic criteria and greater public awareness. But these bureaucratic phrases are cold comfort to a young mum wondering why her three-year-old insists on lining up his toys in strict queues.
As I peeled back layers of medical history to write NeuroTribes, I found a number of issues at play behind the increase in diagnoses. Among them was the story of a very determined young mother named Lorna Wing, who was a psychiatrist at University College London.
When Lorna's daughter, Susie, was diagnosed in the 1960s, autism was considered to be a very rare condition. There was no concept of a broad autism spectrum that includes both chatty Doctor Who fans and intellectually disabled adults who require assistance in daily living. Instead, autism was widely considered to be a rare form of infantile psychosis caused by 'refrigerator mothers' who were unable to offer their children adequate love and affection.
This tragically misguided theory had a catastrophic effect on families as children were sent away to custodial care facilities that were little more than warehouses for the 'severely subnormal', while many parents like Lorna and her husband John bore unspeakable burdens of guilt, shame, and grief.
When I interviewed Lorna, she told me that she thought the theory that autism was caused by neglectful parenting was "bloody stupid" from the start. She and John were both warm and affectionate people who doted on their daughter, but Susie didn't respond in the ways that a typically developing child would. She never directed her mother's gaze toward an object of mutual interest by pointing, for example. And when Susie had an imaginary tea party, she always sipped her imaginary tea alone.
Lorna wanted to spare other families the anguish of raising an autistic child in a world that offered few forms of support and resources for special education. In the 1970s, Lorna and her assistant Judy Gould undertook an ambitious survey for the Medical Research Council to locate all the children with cognitive disabilities whose families needed assistance in Camberwell, south London. The two researchers found many more children who exhibited the characteristic traits of autism than the prevailing theories would have predicted. They also found that the range of clinical presentations was much broader and more colourful than most clinicians believed. In other words, Judy told me, "these children didn't fit into nice, neat boxes."
Lorna and Judy lobbied their peers to replace the narrow conception of autism - which made it impossible for many of these children to get the help that a diagnosis would make available - with a much broader and more inclusive model that they named the autism spectrum. They also introduced a new diagnostic category, Asperger's syndrome, to make services available to highly verbal teenagers and adults. And the surge of new diagnoses began - just as Lorna and Judy predicted it would.
To them, this was good news; it meant help was more readily available to those who needed it. Unfortunately, people who were ignorant of their work were quick to attribute the rising numbers to the MMR vaccine, pesticides, mercury, wi-fi, and any number of other factors in the modern world.
Lorna knew, however, that people like her daughter have always been part of the human community - hidden behind other psychiatric labels, confined behind the walls of institutions, or struggling to get by with no diagnosis at all. This is not just a theory: in recent years, two major studies (one in the United Kingdom and one in Sweden) confirmed that the prevalence of autism hasn't gone up in recent years. The 'tsunami' of autism diagnoses is actually an epidemic of recognition. We now know that there are a large number of autistic people in our communities - needing help, education, housing, psychological services, reasonable accommodations in the workplace, and ways of making meaningful contributions with the special gifts of their atypical minds.
The problem with seeing people on the spectrum as a historical anomaly - as tragic victims of the toxic modern world - is that society will squander scarce and precious resources on hunting for causes and conspiracies, when what we should be doing is building more support systems for autistic people and their families. The fact that families in the UK still often have to wait years for a diagnosis indicates that the work of changing the world that Lorna and Judy embarked upon in Camberwell 40 years ago has barely begun.
Steve Silberman is the author of NeuroTribes: How to Think Smarter About People Who Think Differently.