Autism and the brain: What is really different neurologically

Autism is not a behaviour that can be unlearned – it is a neurological developmental difference that is deeply rooted in the functioning of the brain. The question of whether autism should be understood as a disorder or a variant of human perception is currently being re-evaluated. The focus is increasingly on the biological causes, neurological development and complex manifestations of the autism spectrum.

What it's all about:

what is scientifically proven about brain development in autism

what anatomical characteristics are present

the different forms, such as early childhood autism, Asperger syndrome and atypical autism,

and how autism and disability relate to each other.

What is autism? A neurobiological classification

The definition of autism and Asperger syndrome has changed significantly in recent decades. Today, the term autism spectrum disorder (ASD) is most commonly used. It encompasses various forms of autism that differ in severity, symptoms and support requirements.

In medical terms, ASD is a neurologically based developmental disorder that begins in early childhood. Early brain development in autism shows measurable differences from that of non-autistic children, particularly in areas related to language, emotional processing, social cognition and sensory stimuli.

How does autism manifest itself in the brain?

Modern imaging shows that the brains of people with autism differ structurally and functionally. Research describes an altered relationship between local and global connections in the brain: while certain regions are overly connected, there is a lack of extensive networking, especially in areas related to social interaction, language and empathy.

In children with early childhood autism, brain growth is often above average in the first years of life, but slows down later on. Even in adulthood, people with early childhood autism show differences in the volume and activity patterns of the amygdala, corpus callosum and prefrontal cortex.

These neurological characteristics explain the occurrence of autistic symptoms such as sensitivity to stimuli, social insecurity or monotonous speech patterns – they are not arbitrary, but rather an expression of a biologically and neurologically anchored way of perceiving the world.

What are the typical symptoms of autism?

A central symptom of autism (ASD – autism spectrum disorder) is an altered processing of social and sensory stimuli. Typical symptoms include difficulties in social interaction, stereotypical behaviour patterns and severely restricted interests.

However, autism is not a bonding disorder. People with autism do form bonds – but in their own way. Withdrawal is often a defence against overstimulation, not an expression of a lack of empathy.

According to recent studies, autism affects around 1–2% of the population, although many people with mild autism are not diagnosed until adulthood.

Autism and disability – how are they related?

Autism and disability have a complex relationship. However, autism is not always accompanied by intellectual disability. Although cognitive impairments are more common in early childhood autism, this is not true for all forms of autism.

In Asperger syndrome or high-functioning autism, intelligence is usually average or above average, but everyday life can be severely hampered by sensory processing, social insecurities or emotional self-regulation.

Furthermore, autism is often classified as a disability in a medical context because certain everyday skills are impaired – not because there is a general deficit.

What forms of autism are there?

Diagnostic manuals traditionally distinguish between:

– Early childhood autism (infantile autism)
– Asperger syndrome, named after Hans Asperger
– Atypical autism, in which not all core criteria are met

In current medical practice – e.g. in child and adolescent psychiatry – the term "autism spectrum" is often used to reflect the diversity of the condition. The diagnostic criteria for early childhood autism focus on early symptoms before the age of three.

The term high-functioning autism is no longer used uniformly by experts, but in practice often describes people with Asperger syndrome or similar characteristics.

What are the causes of autism?

According to research, the possible causes of autism are genetic, biological and neurological. There is ample evidence of genetic causes involving the interaction of multiple gene variants. In addition, prenatal risk factors such as complications during pregnancy, infections or environmental factors also play a role.

Earlier theories about the link between autism and mercury poisoning are now considered disproved, as is the false assumption that autism is caused by vaccinations. The idea that autism is more common in vaccinated children has long been scientifically disproved.

The cause of autism therefore lies in a complex mixture of genetic predisposition and biological development – not in upbringing or social environment.

How is autism diagnosed in childhood?

In child and adolescent psychiatry and psychotherapy, diagnosis is based on behavioural observations, standardised tests and interviews with parents and caregivers. The decisive factor is whether the characteristics of autism become clearly visible before the age of three – this is usually the case with early childhood autism.

A diagnosis of atypical autism is made when existing symptoms do not meet all the criteria or appear later in life. This is why ASD sometimes remains undiagnosed for a long time, especially in children and adolescents with a high degree of adaptability.

How do adults experience a late diagnosis?

Many adults report that they felt "wrong", "out of place" or "alien" for long periods of their lives – without having a clear explanation for it. This feeling of being different without being able to name it often persists throughout childhood, adolescence and early adulthood. Looking back, many describe how they reacted more sensitively to things than others as children, immersed themselves deeply in certain interests or had difficulties in social groups. However, because they were above average in terms of verbal skills, performance or adaptability, their autism usually went unnoticed by those around them – and was not even considered.

The late diagnosis – often in their thirties, forties or even later – initially brings a phase of confusion for many, but then deep relief. Finally, there is an explanation for what was previously considered "too sensitive," "too direct," "socially awkward," or "complicated." The finding is not a deficit, but a relief: the diagnosis helps them to no longer interpret their own behaviour as personally flawed or antisocial, but as part of an autism spectrum disorder that is neurologically rooted and has its own logic.

For many people with autism, the late diagnosis opens up a new way of looking at their own lives. Many interpret social failures, professional crises or interpersonal misunderstandings differently in retrospect – no longer as personal failures, but as the result of an unrecognised neurological peculiarity. Symptoms such as sensory overload, exhaustion after social contact or the need for clear routines also gain a comprehensible framework through the diagnosis.

A central issue for adults diagnosed late in life is masking. Many have learned over decades to appear as inconspicuous as possible through conscious strategies – such as imitating social patterns, learning appropriate body language or suppressing their own impulses. This social adaptation may work on the surface, but it often comes at a high price: mental exhaustion, chronic stress, inner tension or even depressive episodes are common consequences. The diagnosis creates the space to recognise and question this masking for the first time – and, in the best case, to gradually let go of it.

A late diagnosis therefore enables a more honest approach to one's own needs and limits. After diagnosis, many people begin to question how they live their lives: Do I have to participate in every social event? Do I have to work in an open-plan office? How much time do I need to myself to feel stable? The answers vary, but they are based on a new self-image that is no longer focused on adaptation but on authenticity.

In addition, diagnosis often provides access to concrete help for autism – such as therapeutic support, coaching, assistance in the workplace or networking with other autistic people. It is often through contact with like-minded people that people first realise: "I am not alone." The realisation that many others have had similar experiences can be deeply relieving – and in many cases mark the beginning of a more stable, self-determined phase of life.

Why understanding is more important than adaptation

People with autism experience the world in a way that is not "wrong" but simply different – neurologically, sensorily and emotionally. The idea that they should adapt to a supposedly normal environment is therefore too simplistic. Rather, they need an environment that is willing to adapt to this different way of perceiving the world – not the other way around. After all, what is second nature to neurotypical people can be a source of constant overload for people on the autism spectrum.

Support for people with autism does not begin with correction or behavioural training, but with understanding. This understanding applies not only to education and therapy, but to everyday life in all its diversity: in schools, at work, in relationships, in dealings with authorities, and in medical care. Where autism is viewed as a deviation, additional stresses often arise – due to demands that are organised in a way that does not take into account a person's neurological profile.

In the context of treating autism, the focus is therefore not on healing. Autism is not a disease that needs to "go away" or "disappear through therapy." It is about improving quality of life – under conditions that the affected person themselves finds relieving, coherent and meaningful. This includes protection from stimuli, communication aids, clear processes, scope for planning, avoidance of unnecessary change – but also the opportunity to withdraw without having to justify oneself.

What is specific to autism is that needs vary greatly, even with similar diagnoses. Two people with the same form of autism can have completely different requirements for their environment. Some want social connection, others prefer absolute quiet. Some can speak, others cannot. Some need visual structures, others a high degree of self-determination. There is no "one-size-fits-all" solution for autism – but there is a common denominator: the desire to be understood without constantly having to explain oneself.

A growing social understanding of neurodiverse perception can make a big difference here. When teachers know why a student does not function well in group work but thrives when working alone. When employers understand that an employee prefers to communicate in writing. When authorities allow forms to be completed in a structured email rather than in a conversation. None of this is special treatment – it is simply barrier-free thinking.

Autism is not a disability, but there is overlap where people on the autism spectrum encounter systems designed for neurotypical functioning. This is where barriers arise – not in the brain of the person affected, but in the structure of their environment. Those who take autism seriously do not question the person, but the norm by which they have been measured.

Understanding creates space – adaptation restricts. And those who are understood have less need to bend themselves out of shape. That is why a respectful, informed and accepting approach to autism is not a question of leniency or patience, but of justice and equality.

Conclusion: Autism is a neurological variant – not a disease

Autism is listed in the fifth chapter of the DSM-5 as a neurological developmental disorder – and that is exactly what it is not: it is not a mental illness or disorder, but a variant of human brain development.

Autism means a different way of thinking, feeling and living. We owe the discovery of autism to research, the exchange of experiences – and the courage of many affected individuals to talk about their inner world.

Anyone who seriously encounters autism and the neurological perspective often described here recognises that autism is not a problem that needs to be solved, but a reality that needs to be understood.

Related Articles

1. Famous people with autism: these stars have Asperger's syndrome

2. What modern research reveals about autism in adulthood: new perspectives on high-functioning autism in adults

3. Autism in adulthood

4. Famous people with autism: these stars have Asperger's syndrome

5. Autistic Fantasy

6. Childhood trauma – Forms: These are the most important cPTSD symptoms