Regionspsykiatrien Horsens

This page provides you with information about autism in adults.

What is autism?

Autism is a developmental disorder. It is seen both in people with normal or high intelligence and in people with developmental impairment. People with autism can have vastly different capabilities. The need for support in their daily lives therefore also differs.

Signs of autism

What causes autism?

There is no single reason why people develop autism. However, research shows that genetics constitute the main cause. Here, many genes are involved, meaning that there is not one single gene that causes autism.


Research has also shown that some close relatives of people with autism have what is called ‘the broad phenotype’. This means that they have more traits from autism than the rest of the population without meeting the criteria for autism.  


Environment is also of importance

The prevailing theory is that the different development begins in the embryonic stage. This includes changes in connections between central areas of the brain.


Genetics alone cannot explain the changes in the brain. Likewise, genetics cannot explain the wide variations within the autism spectrum.


External circumstances are therefore also important, for example premature birth and certain impacts on the unborn child increase the risk.  These impacts may, for example, be infections or toxic substances.


In the vast majority of cases of autism, the exact cause is not known. Regardless of the cause, however, it is a congenital condition.  It gives rise to a different development of the brain.

In a way, I’m terribly ill-equipped to survive in this world – I’m like an alien from outer space who is stranded without any sort of guidance manual. But my value as a human being is intact. My self-awareness is also unimpaired. I find there is a lot of importance, value and meaning in my life – and I have no desire to be cured of being myself. Accept that we are equal strangers vis-à-vis one another, and that my personality is not just a damaged version of yours.
Jim Sinclair – adult with autism


Samtale i psykiatrien

Concomitant disorders

It was almost as if my identity had been locked in a safe all my life, and out of the blue I was given the key. I was allowed to become the person I’ve been all along. I liken it to when homosexuals ‘come out’. They don’t change in any way to how they’ve always been, but all of a sudden they stand by who they are, are open about it and acknowledge it, and that’s what I was able to do following my diagnosis – I could stand up and say: ‘This is me, and it’s actually perfectly OK.’
Louise Egelund Jensen – author

Treatment of autism

Autism is a life-long condition. But behaviour changes considerably at different stages of life, which is why it is also necessary to adapt interventions etc. throughout the person’s life.
Theo Peeters – specialist in autism”

Advice for people who have autism



I experience a thousand details – not a coherent whole. When I experience something in its entirety, it isn’t certain that it’s the right whole. The context for me might be completely different than for everyone else around me. I feel suffocated by the huge number of impressions. I have to devote so much energy to sorting out all this input that I am easily overwhelmed.
Annie – adult with autism



Advice for relatives

Text on this page updated April 2022 (version 1.04).

Most recently revised by: Ulla Klänning, Consultant at the Psychosis Clinic, Aarhus University Hospital – Psychiatry.