Autism pioneer Uta Frith wants to dismantle the spectrum. After a career spent grappling with the condition’s neural underpinnings, she is unwavering in her controversial call to scrap our current view of it and start again. Frith鈥檚 influence on our ever-shifting understanding of autism has been monumental: she developed two landmark theories about how autistic minds might develop differently to neurotypical ones, and was among the first to test ideas like these using newly available brain scanners in the 1990s. Since then, the number of autism diagnoses has sharply risen, especially among women and girls 鈥� largely because of a softening and broadening of how we define the condition. But Frith thinks that many people at the milder end of the spectrum have little in common with those who are profoundly autistic. 鈥淭here鈥檚 absolutely no overlap,鈥� she says. 鈥淭hat is the sign that the spectrum isn鈥檛 holding.鈥� In this video, she sits down with New 女生小视频 editor Thomas Lewton to discuss autism.

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The age at which children are diagnosed with autism seems to be partly influenced by their genetics, which may also affect how the condition develops.

鈥淭his really provides support for the idea that autism is actually potentially multiple conditions,鈥� says at the Flatiron Institute in New York, who wasn鈥檛 involved in the study.

Autism is a neurodevelopmental condition, characterised by difficulties with social interactions, plus restricted behaviours and interests. The World Health Organization estimates that about .

鈥淭he key question that we were interested in was: why is it that there鈥檚 some autistic people who are diagnosed later on in life?鈥� says at the University of Cambridge.

To find out, he and his colleagues compiled data on people who were diagnosed with autism between the ages of 5 and 17. Their carers completed a questionnaire about their social, emotional and behavioural development, to help the team see if these factors were associated with their age at diagnosis.

The sex of a child, as well as their socioeconomic status, have previously been associated with age at diagnosis 鈥� with early diagnoses being and 鈥� but the team鈥檚 analysis showed that these influences are actually quite weak. 鈥淣one of the factors typically explain greater than 10 per cent of the variance,鈥� says Warrier.

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Instead, the team found evidence of autistic children developing along different trajectories. 鈥淲hat we found was that autistic people were grouped into two broad groups,鈥� says Warrier. One group started experiencing difficulties early in life and these stayed largely constant. The other had fewer difficulties in early childhood, but experienced more in late childhood and early adolescence. This explained 鈥渁nywhere between 10 to 25 per cent of the variance in age of autism diagnosis鈥�, he says.

Further, the researchers found that these differences between the two groups were reflected in the children鈥檚 DNA, which had previously been collected. Those who were diagnosed later tended to have a different set of common genetic variants than those diagnosed earlier, which explained 11 per cent of the variation in age of autism diagnoses. The team didn鈥檛 have the necessary data to look for rare variants or those that arise spontaneously, rather than being inherited.

Despite these two trajectories, there is no sign of a hard separation between them, says Sauerwald. 鈥淵ou have overlap between the groups, probably because they鈥檙e not perfectly separable,鈥� she says. Warrier similarly describes them as existing 鈥渙n a gradient鈥�.

A revolutionary new understanding of autism in girls

By studying the brains of autistic girls, we now know the condition presents differently in them than in boys, suggesting that huge numbers of women have gone undiagnosed

He emphasises that neither group should be thought of as having milder or more severe autism, which research increasingly suggests takes multiple forms. In July, Sauerwald and her colleagues published a study in which they found , with differing symptoms, behaviours and underlying genetics.

Warrier鈥檚 team also found that the children diagnosed later were more likely to have genetic variants associated with other conditions, including ADHD and post-traumatic stress disorder. In Sauerwald鈥檚 study, her team found a similar link between late autism diagnosis and ADHD, which, like autism, is a form of neurodiversity. Why this link exists is unclear, says Sauerwald. 鈥淭here鈥檚 a surprising lack of data on ADHD,鈥� she says, especially about the specific symptoms people experience.

Better understanding the potential subtypes of autism could eventually help improve diagnostic practices and lead to more tailored support for autistic children and their families. 鈥淭hat can only lead to improvements in the quality of life for individuals 鈥� when we can better understand their condition, and how to help them, and what it is that they need exactly and what they don鈥檛 need,鈥� says Warrier.

On Monday, the US government announced two initiatives related to autism. It will update labelling on the common painkiller paracetamol, also called acetaminophen, warning use during pregnancy may increase the risk of autism and ADHD in children. It will also approve a drug called leucovorin for use in some children with autism spectrum disorder (ASD). Neither of these moves is based on robust scientific findings, and they are likely to have minimal effect on autism rates in the US.

The announcement comes after the country鈥檚 highest ranking public health official, Robert F Kennedy Jr, pledged in April to identify the causes of autism by the end of September. US President Donald Trump touted the initiatives as 鈥渉istoric steps to confront the crisis of autism鈥� during a press conference.

This framing reveals either a misunderstanding or a misrepresentation of what we know about autism. There is no crisis 鈥� rates of autism began to increase rapidly in the 1980s as diagnostic criteria for the condition expanded. Over the past few decades, a higher level of awareness and recognition of the symptoms of autism has also contributed to an increase in autism diagnoses.

As for the cause of the condition, there is little evidence suggesting paracetamol is to blame. It is true multiple studies have suggested paracetamol use in pregnancy may increase the risk of autism in children. A of 46 studies found 27 of them identified a significant association between using paracetamol in pregnancy and children having a higher risk of neurodevelopmental conditions such as autism. But just because there is a relationship doesn鈥檛 mean paracetamol causes autism 鈥� other factors could be at play.

And there are conflicting findings from other studies. For example, a of nearly 2.5 million children found a slightly higher risk of autism in those exposed to paracetamol during pregnancy, but after comparing children exposed to the painkiller with those of their unexposed siblings, the effect disappeared. 鈥淚t was the family history that mattered and not the use of paracetamol,鈥� said at University College London in a press statement. 鈥淩esearch has shown that any apparent marginal increase [in autism] as a result of paracetamol in pregnancy tends to disappear when the analyses take into account the factors that matter the most鈥�, such as genetics, which decades of research has indicated is a primary contributor to the condition.

During the press conference, Trump said pregnant women shouldn鈥檛 take paracetamol for pain or fever during pregnancy unless they 鈥渃an鈥檛 tough it out鈥�, and they 鈥渟hould talk to their doctors for more information鈥�. However, the US Food and Drug Administration (FDA) acknowledged in a 聽a causal relationship between paracetamol and autism hasn鈥檛 been established and said in a paracetamol remains the safest widely available painkiller for use during pregnancy. 鈥淸It] is the only over-the-counter drug approved for use to treat fevers during pregnancy, and high fevers in pregnant women can pose a risk to their children,鈥� the agency said. Fever during pregnancy has been linked to pre-term birth and in the fetus.

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The FDA also announced it will for people with cerebral folate deficiency, a condition that impairs uptake of vitamin B9 in the brain. Some research indicates upwards of of autistic people may also have this condition, which results in similar symptoms, including communication and sensory processing issues.

Leucovorin, a form of vitamin B9, is already available for treating deficiencies of this vitamin as well as side effects from certain cancer medications. Early evidence suggests it might improve some severe autism symptoms, too. For instance, a treated 23 autistic children with language impairments using two doses of leucovorin daily while a separate group of 25 children received a placebo. After 12 weeks, 65 per cent of children receiving leucovorin saw a clinically meaningful improvement in verbal communication compared with 24 per cent of those in the control group.

But so far, all of the studies on leucovorin and autism have been small, and most indicate only modest improvements. A larger clinical trial is underway, the . 鈥淎ny evidence available at this point is exceptionally tentative and would not be considered robust,鈥� said at Durham University in the UK in a press statement. 鈥淲hilst medications may help with very specific aspects [of autism], there is no medication or treatment that actively cures or erases autism.鈥�

Following the announcement, the US Department of Health & Human Services clarified in a statement that 鈥渨hile promising, it is important to note that leucovorin is not a cure for ASD and may only lead to improvements in speech-related deficits for a subset of children with ASD鈥�.

Kennedy, with Trump鈥檚 backing, has made tackling the 鈥渁utism epidemic鈥� a pillar of US public health policy. They both portrayed these policy changes as remarkable progress made in a short period of time. But the science suggests neither avoiding paracetamol in pregnancy nor taking leucovorin will significantly affect autism as Trump and Kennedy have claimed. Instead, the most likely outcome of these initiatives is they will sow confusion around how and when to safely treat pain or fever during pregnancy.