Tryti has worked with assessing and treating children and adolescents with neurological functional and developmental disorders. He is now a researcher in a project investigating the rise in autism prevalence.
He explains that the diagnostic criteria for autism have not changed since the late 1990s.
"These criteria are the same, and they're very strict," he says.
Tryti explains that children who meet these diagnostic criteria often have very limited eye contact, develop language very late, and struggle to use language socially.
This can be distressing and exhausting for families.
"It’s difficult to imagine that these children wouldn’t have been identified earlier, which is why there's reason to believe this reflects a genuine increase," he says.
Three times as many cases at Oslo University Hospital
Petra Aden, chief physician at Oslo University Hospital and leader of the neurorehabilitation department, agrees.
"15 years ago, we would have diagnosed this type of autism in the same way as we do now," she said at a public event in Arendal in 2025.
"But for older children, and especially girls, it may be that certain taboos have been broken, leading to more diagnoses," she suggested.
Annonse
Aden's department at Oslo University Hospital has seen referrals of children triple since 2012. In other words, a formidable increase.
"This affects us greatly. We lack resources everywhere, both in healthcare services and in municipalities," she said.
Looking ahead, Aden warns of a massive and growing need for specialists and other resources in this field.
Largest increase among children of immigrants
Over the past decade, many working in habilitation have observed that the rise in autism diagnoses is most pronounced among children of parents from low-income countries.
"This challenges much of what we think autism is," he believes.
"Most research articles on autism begin by emphasising that autism is a neurodevelopmental disorder with high heritability. Even though high heritability does not rule out the possibility that the environment can play a role, people are used to thinking of autism as something that isn't 'triggered' by the environment," he says.
Heritability cannot explain everything
"High heritability means it's not entirely random which children are diagnosed – they carry factors from birth that increases the likelihood of meeting the diagnostic criteria," he says.
But genetics alone cannot account for the steep rise seen in recent years, he argues.
"The occurrence of conditions determined by heredity should be fairly constant and not vary much over time or between demographic groups," he says.
When such a sudden change occurs in something many believe to be innate, we need to take a step back and try to understand what we're really dealing with, says Tryti.
Mapping the patients
When Akershus University Hospital looked more closely at the development of autism diagnoses among those under 18, they found a sharp increase dating back to the early 1990s. This matches the figures published by NIPH.
"The challenge today is that far more children are diagnosed than 15 years ago, yet we know far too little about what characterises these 'new' children. We need updated knowledge so that these children and their families receive the help they both need and are entitled to,” says Tryti.
Researchers don't yet know the cause, but two factors stand out:
The first is immigrant background.
The second is socioeconomic status.
According to NIPH's report from early summer, autism diagnoses are increasing among preschool children of parents with immigrant backgrounds, particularly from Asia and Africa.
When comparing children of parents with the lowest and highest incomes, the increase is almost twice as large among children of low-income parents.
Tryti notes that this pattern is not unique to Norway.
"Across all Western countries, autism in preschoolers is far more common among children of immigrant families," he says.
Diabetes and obesity
Petra Aden points to research showing that what happens during pregnancy may increase the risk of autism.
"We know, for example, that diabetes and obesity can raise the likelihood of having a child with autism," she said at the public event.
Other researchers have looked at a potential link between autism and screen use among preschool children.
But Einar Aasen Tryti does not believe the explanation lies in just one or two factors.
"If autism were linked to obesity, the increase should have followed the increase in obesity that began in the early 1980s," he says. "And while most children have a much higher screen time than health authorities recommend, the vast majority don't receive an autism diagnosis."
A complex interaction
Risk factors, Tryti explains, interact in complex ways with genetics. That makes it extremely difficult to separate cause from effect.
"As of today, there's not enough information to draw firm conclusions," he says.
Tryti believes the issue must be seen in the context of broader societal changes in recent decades.
"It's very important not to place blame on parents or individual families. When the pattern differs across entire social groups, it's clear that society itself must be examined – and that we collectively bear responsibility for understanding these developments," he says.
Greater awareness of autism
Alexandra Havdahl, head of the Autism Study at NIPH and one of the authors of the new report documenting the increase in Norway, agrees that no single factor explains the changes.
Still, she points out that a significant part of the trend reflects greater awareness, alongside changes in diagnostic criteria and referral practices.
"This is also shown in international research," says Havdahl.
Alexandra Havdahl is a researcher and head of NIPH's Autism Study.(Photo: Marte Dæhlen)
Researchers warn against speculation
At the same time, the NIPH report shows the same as Einar Tryti's mapping: Autism has increased among children with immigrant backgrounds and in families with lower socioeconomic resources.
"What this means, and why it's happening, is still unknown," Havdahl points out.
These groups have historically been underrepresented in autism research and statistics.
Havdahl is concerned that speculation by professionals in the media about what they think the cause might be could be distracting. The focus should be on how we can help the children and their families, she writes in an email to Science Norway.
Great needs, limited resources
The gap between the need for autism services and the resources available is already significant.
Havdahl cautions that speculation may also fuel stigma and place unnecessary strain on parents.
"For now, there isn’t enough research to give clear answers. We should expect the explanations to be complex,” according to Havdahl.
Long waiting times
While more research is needed, Havdahl highlights urgent challenges: In many cases, families wait more than a year for an autism assessment.
This is troubling because early support and tailored interventions are crucial for the children, she writes. Such support shapes how children develop, function, and thrive.
"It's important to acknowledge the great diversity of challenges, resources, and needs. We need more research that can contribute to better and more personalised follow-up," she says.
