Experts now believe that humans have had autism for millenia. But the history of autism is one of misunderstanding, with profound and often negative impacts on an untold number of lives.

The first written description of a person with autism appeared circa 1800. Dr Jean-Marc-Gaspard Itard, a French physician, took interest in a boy who had been found naked, scarred and abandoned in a forest. The boy did not speak, seemed deaf to speech, and spent time rocking and shelling beans. Against contemporary medical opinion, which dismissed the boy as a imbecile, Itard cared for the boy and experimented with behavioural programs to help him, later publishing his notes in a book called The Wild Boy of Aveyron. It outlined a compassionate approach to care that would rarely be heard of again in the decades to come.

The modern articulation of autism as a spectrum disorder emerged in the late 1930s. Dr. Hans Asperger, an Austrian pediatrician, articulated Autismus as a “natural entity” with distinctive characteristics and yet huge variation, appearing frequently in both the most gifted people and those with severe challenges for socialization and learning (Silberman, 98). His ideas were informed by his observation of over two hundred children in care at Vienna’s Children’s Clinic.

The political climate of the times, however, ensured that Asperger’s research findings would not be communicated in full for a long time. Nazi eugenics policies targeted people with cognitive or physical disabilities, so Asperger selectively focused his public presentations on four unsually gifted children whom he called “little professors.” They seemed oddly in their own world, but their apparent weaknesses, Asperger argued, were also the source of their high intelligence and creativity in sciences and maths. Accordingly, the breadth of Asperger’s work was obscured, says Steve Silberman in his history of autism, NeuroTribes. It became known internationally in a limited way, as Asperger’s syndrome, an autism profile that entails high intelligence (Silberman, 123–130).

Meanwhile, Nazi oppression led some of Asperger’s close colleagues to flee to America, where they met and started working with Leo Kanner, an Austrian child psychologist at Johns Hopkins University. Like Asperger, Kanner noticed he had eleven patients who seemed to live in their own worlds, not speaking or repeating limited speech, and taking amusement from activities such as spinning pot lids. Publishing his findings in American medical journals, Kanner’s ideas about autism became the conventional wisdom.

Unlike Asperger, Kanner believed autism was a rare phenomena of early childhood. He also took from contemporary academic ideas about toxic parenting, and developed the view that autism is caused partly by cold, hostile parents. As a result, mothers of autistic children suffered blame and stigmatization, while people with autism were institutionalized and given experimental behavioural treatments such as electric shocks and anti-psychotic drugs. And although awareness of autism grew, many cases were never diagnosed, or wrongly diagnosed as other mental health disorders that led people to be improperly medicated for decades.

It took parents of autistic children to change things. An important one was Dr. Bernard Rimland, an American doctor who in the 1960s convincingly overturned the thesis that cold parenting caused autism. In his published research, he showed that autism is biological. He developed a checklist for identifying autism, and turned the attention of medical researchers to the role of the brain.

More controversially, Rimland supported new treatments for autism, including Applied Behavioural Analysis. Developed by Ivar Lovaas, a psychologist at UCLA, the learning-theory based program of rewards and punishments aimed to get children with autism to act more “normal” and acquire everyday life skills, and to get parents involved in teaching this at home. Versions of it are still practiced today. Rimland also experimented with special diets and vitamins, particularly the gluten- and casein-free diet, which many parents found effective and has given rise to a plethora of biomedical interventions available today.

In 1980, a tight definition of autism spectrum disorder was included in the Diagnostic and Statistical Manual of Mental Disorders (DSM) for the first time. But with the accrual of more research, later versions of the DSM loosened the diagnosis criteria. Consequently, the number of diagnoses began to expand dramatically—leading to greater awareness, but also new misunderstandings. Data from the United Kingdom shows the number of autism cases leaping from 4 in 10,000 in the 1966 to 110 in 10,000 in 2011. Reacting to what appeared to be an explosion of autism in the 1990s, media reporting incited parental fears and researchers looked again for environmental causes.

In response, a movement of adults living with autism started to organize against popular misconceptions. The Autistic Self Advocacy Network, aligning itself with the disability rights movement, put forth the idea that autism is not a disease in need of a “cure,” but a disability in need of accommodation and understanding.

Today this point of view exists in conjunction with more and varied research seeking to discover the neurological and biological mechanisms that underly autism and related disorders. A long list of therapies to ameliorate the physical ailments associated with autism and encourage social and cognitive skills continues to develop. Autism is much more widely recognized and accepted than it once was, though scientific research has much yet to uncover, and many experts would say it is still society, not people with autism, that needs to change.