What we know about the causes of Autism – a scientific summary
For decades, researchers and clinicians have sought to understand the causes of autism. Recently, there’s been renewed media attention and political debate around data collection and theories about environmental triggers driving what some call the “autism epidemic.” It’s a good moment to step back and take a look at the history: what we know — and what we don’t — about the roots of autism.
Although the word autism first appeared in the early 1900s, it wasn’t recognized as a distinct diagnostic category until the 1950s. Because the diagnosis emerged within psychiatry — and under the influence of psychoanalytic theory — early explanations focused on parenting. Specifically, the now-debunked “refrigerator mother” theory claimed that emotionally distant mothers caused their children to withdraw into themselves.
This theory was not only damaging to families, but difficult to disprove. (After all, how do you prove you’re not cold or distant?) It wasn’t until the latter half of the 20th century, when attention shifted toward genetics and neurobiology, that researchers began moving away from blaming caregivers.
In the 1970s and 1980s, studies began to support a biological basis for autism. Researchers noted significantly higher rates of autism among identical twins and within families — pointing toward heritability.
But in 1998, progress was derailed. A now-infamous study by Andrew Wakefield and colleagues falsely linked the MMR (measles, mumps, and rubella) vaccine to autism. The study involved just 12 children — 11 of whom were boys — admitted to a pediatric gastroenterology clinic in the UK. Of the 12, nine had autism, one had psychosis, and two had encephalitis.
The authors suggested a connection between these diagnoses and the MMR vaccine. But there were major problems with the study:
The sample was small and not randomly selected.
Wakefield failed to disclose that the study was funded by lawyers pursuing lawsuits against vaccine manufacturers.
Ethical violations and procedural issues abounded.
Ten of the study’s authors have since publicly retracted its conclusions. Wakefield’s medical license was revoked, and the study is widely regarded as fraudulent. (He also published a second flawed study in 2002, which gained far less attention but echoed similar claims.)
The damage, however, was done. Vaccine rates dropped, and misinformation spread globally — a cautionary tale of how flawed science can spark public health crises.
Since then, research has largely returned to more rigorous and responsible inquiry. Current evidence strongly supports a genetic and neurodevelopmental origin for autism:
No single gene causes autism, but hundreds of genes appear to contribute in complex ways.
No single environmental factor has been found to cause autism either, though prenatal influences and gene-environment interactions are being studied.
The takeaway? Autism is not caused by parenting. It’s not caused by vaccines. And it’s not caused by any one thing. It emerges through a complex interplay of biology, development, and individual variability — which is exactly why it’s understood as a spectrum.
Continuing to study the roots of autism is essential — not to “cure” or eliminate it, but to better understand and support autistic individuals. But it’s equally important that our curiosity be grounded in respect, not panic.
Wakefield’s legacy is a reminder of what happens when bias, politics, and unethical science take precedence over evidence. If we want to move forward, we need to ask better questions, stay open to complexity, and keep autistic voices at the center of the conversation.
