One in 160 children has autism but several recent studies have reported rates that are substantially higher, according to the World Health Organization (WHO).
ASD is considered a developmental disorder because — although it can be diagnosed later in life — it begins in early childhood and tends to persist into adolescence and adulthood.
The level of intellectual functioning in autistic people varies hugely, ranging from profound impairment to superior non-verbal cognitive skills. It is estimated that around 50% of people with autism also suffer from an intellectual disability, according to the WHO.
There is a wide range of symptoms in autistic people. Some of the main symptoms include communication problems like delayed speech development, and difficulty in social interactions, such as making friends, maintaining eye contact, reading people's body language or facial expressions, and expressing how they feel. Repetitive behaviors and strict routines may also be noticed, like repetitive body movements or finding it difficult to adjust even to small changes.
"There are autism spectrum disorders in which all autistic symptoms appear in a very strong form. These include the so-called syndrome autistics. In them, there are often severe underlying developmental disorders that then lead, among other things, to the symptoms typical of autism," says Hannelore Ehrenreich, the head of the Department of Clinical Neuroscience at the Max Planck Institute for Experimental Medicine in Göttingen, Germany.
"Autism is an extremely complex disorder. Research on it has to come from different disciplines," Ehrenreich told DW. Important pillars include psychiatry and neurology, but also genetics and neurobiology. Only in this way is it possible to develop effective therapies for certain forms of autism, she said. This may be necessary, for example, if other serious issues are also present.
These can be neurodevelopmental disorders, difficulties in fine motor skills or pronounced repetitive movements. "This is the case, for example, when a child always sits in the corner and continuously wiggles his head or wrings his hands, making so-called manege movements [movements sidewards with the head]," said Ehrenreich.
Some people with ASD also have savant syndrome, a rare condition where someone has exceptional skills often related to memory, but also art, mathematics and music.
The 1988 film "Rain Man" starring Dustin Hoffmann and Tom Cruise was one of the first films to include a main character with autism.
While the film introduced autism to people on a large-scale and brought attention to the disorder, it is sometimes criticized for having created a stereotype of people with autism.
Dustin Hoffmann's character, Raymond, is an autistic man who can memorize vast amounts of numbers but is incapable of managing his daily life and who lives in a home for people with disabilities. The film was inspired by the life of Kim Peek, an American with exceptional memory abilities who said he could memorize the contents of about 12,000 books.
But highly gifted autistic people are quite rare. Studies determining the number of autistic people who are savants vary, but at least one in 10 people with autism has savant abilities. One study found that 37% of people in the sample exhibited either savant skills or unusual cognitive skills or both.
Ehrenreich cares for one such gifted patient. "If you ask him what's in the phone book on page 923 in the middle column, he can tell you with no problem," said Ehrenreich, "but he can't manage to get dressed in the morning. He puts his shoes on first and then his pants. That means he needs help."
Expert diagnosis essential
Ehrenreich said the diagnosis of "autistic" absolutely must be made by people who are well versed in that specialty. "There are various instruments and tests that help with the diagnosis and back it up. In appropriate centers, specialists can perform these tests," Ehrenreich said. It's just not enough to be a psychiatrist or neurologist. A great deal of experience and expertise is needed to determine whether autism is present and what form it takes.
"About half of the people who are sent to us with suspected autism don't have autism at all. That's where the diagnoses are simply wrong. In addition, autism has become a kind of fashionable diagnosis," Ehrenreich said.
While other conditions can be treated with medication, specific medications for autistic people with severe disorders do not exist. None of the potential medications have led to a breakthrough, such as the endogenous messenger oxytocin, which acts directly in the brain. "As a hormone, oxytocin enters the body through the bloodstream. It has been found to be able to improve social interaction in autistic people in the short term. It doesn't have a lasting effect, though. But through this new experience they're having, it might encourage autistic people to start behavioral psychotherapy." First, however, a diagnosis must be made that is as sound and clear as possible.
Building on the observation that autistic people largely avoid eye contact, scientists have done eye-tracking experiments. This involves a camera recording eye movements. "With this eye-tracking, you can see that the autistic person is not looking at the eyes or mouth of their counterpart, as most people do, but at facial regions that play little role in communication. They then look at the neck or cheek, for example," Ehrenreich said.
Another tool is thermography. It can provide information about the surface temperature of a person's face. "In doing so, you see very characteristic behavior of heat and cold in the face. We were able to show that social stimuli cause a change in the thermo response in the face. This allows us to distinguish social stimuli from purely cognitive stimuli, for example, those based on perception and thinking independent of social interaction," Ehrenreich explained.
"Such tests lead to a relatively objective measure of diagnosis, because they can show how much stress an autistic person experiences when interacting with others." Such a test can help medical professionals and researchers better understand the mechanisms and causes of autism.
There is now an extensive database available, which Ehrenreich started it in 2004. It registers not only autistic people but also people with schizophrenia. With the help of this database, scientists can identify and describe phenotypes. These describe the set of all characteristics that an organism has, including behavioral traits. Those in particular are essential to understanding autism.
"When I started this database, people didn't always take me very seriously. Many thought you could find just about anything with the help of genetic testing or blood analysis," said Ehrenreich, "today, however, it's known that we need to know quite a lot about a person in order to understand where certain disorders and problems originate."
The database is intended to help classify test subjects as correctly as possible. Among other things, this involves determining how severely individual subjects are affected and whether they can be grouped into groups with similar characteristics. "Our goal is to draw more information about autism and its biological causes from this vast heterogeneity."
For severe cases, that can also lead to more targeted therapies. "If I know what the biological cause of a disorder is, I can treat it better," Ehrenreich sums up. Genetic causes are a prime candidate for this. But environmental factors that act very early, for example infections during pregnancy, for example, in utero, can also play a role in the development of autism.
The autist in us
Ehrenreich said that autistic traits are a part of the normal human behavioral repertoire, and only in extreme cases do they result in a disorder.
"If we took the whole population and measured everyone's autistic traits, we would get a very broad spectrum," said Ehrenreich. "We would probably find quite a few people who have distinct autistic traits."
Walking through the hallways of the Max Planck Institute, for example, she repeatedly encounters people who stare fixedly at the floor, completely absorbed in their own data world and in no way eager to communicate. "But that does have its advantages. As a scientist, it's great when they're not partying but working intensively on their research."