Tuesday is World Autism Day. More than 1 percent of the Dutch are autistic. However, because the condition has a major impact on the environment, the number of people affected is much greater. Seven questions about autism to developmental psychologist Gerrit Breeuwsma.

What exactly is autism?

"Autism is a collective name for various behavioral traits: difficulty with social interaction, limitations in verbal and non-verbal areas, less ability to deal with changes and difficulty in filtering information. As a result, stimuli sometimes come in harder."

"You used to be diagnosed with autism if you met all those characteristics. Nowadays we speak of an 'autism spectrum disorder'. Not everyone has the same characteristics to the same degree."

How do you deal with it?

"When dealing with others, we take all sorts of natural things for granted. For people with autism, these natural things do not apply. For example, it is important to adjust your language. We unconsciously use a lot of ambiguities and metaphors. Irony or sarcasm is difficult to distinguish for someone. with autism. So literally say what you mean. "

"Autists, both children and adults, benefit from routine. Stick to a fixed schedule as much as possible. If you deviate from the schedule, it is important to prepare him or her well in advance."

Are the changes brought about by the corona crisis a major problem for autists?

"It can be stressful in families. On the other hand, life is very basic and simple at the moment, and with sufficient regularity and routine it can be pleasant for autists. Moreover, there is no school, something that often costs autistic children a lot of energy."

How does autism develop?

"We don't know yet. It used to be thought that it was up to the upbringing. But that has turned out to be nonsense. Vaccinations were also blamed for a long time. But that assumption was based on fraudulent research that has since been refuted. In more recent research, no link demonstrated. "

Is it hereditary?

"Genes play an important role. A large study in five countries recently showed that autism is approximately 80 percent hereditary. Often autism also occurs in several people in the family. And you have a higher chance of autism if someone in your family has it. "

It seems to be more common in men. Is that right?

"It does seem like that. The chromosomal distribution might explain it: perhaps the double X chromosome protects women against autism."

"Perhaps it is also based on an evolutionary explanation. In the days of our ancestors, men often operated alone. They spent days hunting alone, focused on one thing: the animal they were chasing."

"Women operated in groups. In order to maintain yourself in the group, you had to be able to 'read' the other person, you needed social antennas. Women could therefore be more 'social' than men for that reason."

Does autism not occur at all in women?

"Yes. But it often comes to light later. For example, through a burnout. Because the social aspect in women is often well developed, autism sometimes remains hidden for a long time. They can often function socially, but it costs them a lot. energy."

Gerrit Breeuwsma is a developmental psychologist at the University of Groningen and author of the book Allemaal Autistic. Between help, hope and hype , published by SWP publishing house. More information about autism on www.autisme.nl , the website of the Dutch Autism Association.