New Insights Into Autism and the Brain's Dopamine System
Author: University of Southern Denmark Faculty of Health Sciences
Published: 21 Aug 2026
Publication Details: Peer-Reviewed | Randomized Trial
Table of Contents:
Synopsis - Definition - Overview - FAQs - Insights, Updates - Related Content
Synopsis
This research combines three advanced brain-scanning techniques for the first time to examine the dopamine system, glucose metabolism, and communication between brain regions at once in the same participants, providing a more nuanced view of the biological mechanisms associated with autism. Conducted by scientists at the University of Southern Denmark and Odense University Hospital, the study of 60 adults - 30 autistic and 30 neurotypical - found a higher number of dopamine D2 receptors and greater energy use in certain deep brain regions of autistic participants, and it is the first PET study designed to also look at possible differences between autistic men and women. This matters for autistic people, their families, clinicians, and researchers because it points to the dopamine system playing a more fundamental role than previously thought and raises questions about the frequent overlap between autism and ADHD, where dopamine is also central. The work is careful and measured, noting that it does not explain why autism develops and cannot be used for diagnosis, which makes it a useful and honest reference for anyone, including seniors and people with disabilities, seeking to understand neurodiversity through solid biological evidence rather than speculation.*
At a Glance
- 1 - The study was funded by the Psychiatry Research Fund, Region of Southern Denmark.
- 2 - Around 70 percent of autistic people have one comorbidity, and 40 percent have two or more.
- 3 - The only FDA-approved medications related to autism act on the dopamine D2 receptor to reduce aggression and irritability in autistic children.
- 4 - Laust Vind Knudsen led the work as first author during his PhD, supervised by Professor Tanja Maria Sheldrick-Michel and Professor Manouchehr Seyedi Vafaee.
Topic Definition
- Dopamine D2 Receptor
The dopamine D2 receptor is one of the specialized binding sites that nerve cells use to receive signals carried by dopamine, a neurotransmitter tied to motivation, learning, movement, and reward. As a core component of the dopamine system, the D2 receptor helps regulate how messages pass between neurons, and differences in its number or activity have been connected to ADHD and to other neurological and psychiatric conditions. Its importance in autism research is practical as well as biological, since the only medications approved by the FDA in connection with autism act directly on this receptor, using it to reduce aggression and irritability in autistic children, which is why measuring D2 receptor levels in the brain offers a meaningful window into the neurobiology of autism.
Overview
New Insights into Autism and the Brain
By combining three different brain scans, researchers have gained new insight into the biological mechanisms associated with autism. The findings suggest that the dopamine system may play an important role in autism
How does autism manifest in the brain?
Researchers from the University of Southern Denmark and Odense University Hospital have investigated this question in a new study involving 60 adults.
For the first time, they combined three advanced brain-scanning techniques, allowing them to examine the brain's dopamine system, energy use and communication between brain regions at the same time.
The findings provide a more nuanced picture of the biological mechanisms associated with autism. The study found a higher number of dopamine D2 receptors in autistic people than in neurotypical people, suggesting that the dopamine system may play an important role in autism.
Three Brain Scans Provided a New Picture
Previous autism research has primarily focused on how different brain regions communicate with one another, while only a smaller number of studies have examined neurotransmitters or the brain's energy use.
Because neurotransmitters regulate communication between different regions of the brain, understanding any differences in these chemical messengers is important if we are to better explain why communication between certain brain regions may differ in autistic and neurotypical people.
By bringing all these perspectives together in a single study for the first time, the researchers were able to identify relationships that had not previously been described.
Our study is the first to investigate the neurotransmitter dopamine, the brain's energy use (glucose metabolism) and communication between brain regions in the same study. This gives us a more nuanced understanding of the neurobiological mechanisms associated with autism, says Laust Vind Knudsen, postdoc at the Research Unit for Psychiatry, Odense University Hospital and the University of Southern Denmark.
He is first author of the study, which showed, among other things, that certain deep brain regions in autistic people had both higher energy use and more receptors for the neurotransmitter dopamine than in neurotypical participants.
The study was conducted as part of Laust Vind Knudsen´s PhD project at the University of Southern Denmark and Odense University Hospital, under the supervision of Professor Tanja Maria Sheldrick-Michel as research leader and principal supervisor and Professor Manouchehr Seyedi Vafaee as co-supervisor.
The dopamine System Appears to Function Differently
Dopamine is a neurotransmitter that some nerve cells in the brain use to send messages to one another. It plays a role in, among other things, motivation, learning and movement.
The study showed that, among the autistic people who participated, a higher number of dopamine receptors was associated with higher energy use in the same brain regions.
The researchers also found that the dopamine system influenced the communication between brain regions differently in autistic participants than in neurotypical participants.
Our findings suggest that the dopamine system not only differs between autistic and neurotypical people. They also indicate that the dopamine system affects communication between brain regions differently in the two groups. This suggests that the dopamine system may play a more fundamental role in autism than previously thought, says Laust Vind Knudsen.
New Knowledge About Biological Variation in Autism
The researchers emphasise that the study does not explain why autism develops and cannot be used to make a diagnosis. What it does provide is new knowledge about the biological variation and biological mechanisms associated with autism, and about the interplay between the brain's neurotransmitters, energy use and communication between different brain regions.
The findings are also interesting because many autistic people also have an ADHD diagnosis, and because the dopamine system plays a central role in ADHD.
The findings therefore raise new questions about whether some of the biological mechanisms linked to the dopamine system may be shared by autism and ADHD and could therefore help explain the high prevalence of ADHD among autistic people.
Brain research can help us understand autism better, not in order to change autistic people, but to create greater understanding of neurodiversity and better conditions in society. Our findings also raise new questions about why autism and ADHD so often occur together, which we would like to investigate further, says Laust Vind Knudsen.
A Step Along the Way
The study included 60 adult participants and is the first positron emission tomography (PET) study specifically designed also to investigate possible differences between autistic men and women.
At the same time, the researchers emphasise that larger studies are needed to determine whether the findings are valid and can be replicated in other cohorts of autistic people.
Quick Facts:
What is Dopamine?
Dopamine is a neurotransmitter that nerve cells use to send messages to one another. It plays a role in, among other things, motivation, learning, movement and reward.
For dopamine to work, it must bind to special receivers on nerve cells called receptors. One of these is the D2 receptor, which the researchers examined in this study.
The D2 receptor is an important part of the dopamine system and has previously been linked to, among other things, ADHD and other neurological and psychiatric conditions.
The only FDA-approved medications related to autism specifically affect the dopamine D2 receptor, which is why it was relevant to examine this receptor in the study. These dopamine D2 medications are used to reduce aggression and irritability in autistic children.
What do Neurotypical and Neurodivergent Mean?
Neurotypical is a term used for people whose neurological development and functioning fall within what is considered typical in the general population.
Neurodivergent is a term used for people whose neurological development or functioning differs from what is considered typical. The term includes autism, ADHD, dyslexia and other forms of neurological variation.
(What Is: Neurodiversity, Neurodivergent, Neurotypical: Definitions of neurodiversity, Neurodivergent, and neurotypical, covering the origin of the terms, the neurodiversity movement, and the debate surrounding it.)
Overlap Between Autism and ADHD
Autistic people often have one or more co-occurring diagnoses, or comorbidities.
It is estimated that around 70% have one comorbidity, while 40% have two or more.
ADHD is one of the most common comorbidities. Studies suggest that around 40% of autistic people also have an ADHD diagnosis.
(AuDHD: The Co-occurrence of Autism and ADHD Explained: Learn how AuDHD describes the co-occurrence of autism and ADHD, its DSM-5 recognition, diagnostic complexity, treatment approaches, and community identity.)
(Rong, Y. et al. Prevalence of attention-deficit/hyperactivity disorder in individuals with autism spectrum disorder: A meta-analysis. (2021))
About the Study
Method
The study included 60 adult participants: 30 autistic and 30 neurotypical participants.
The researchers combined two PET scans and one functional MRI scan to examine the brain's dopamine system, energy use and communication between different brain regions at the same time.
This is the first time these three measurements have been combined in a single study including autistic participants.
Funding
The Psychiatry Research Fund, Region of Southern Denmark.
Frequently Asked Questions
NOTE: Researched FAQs by Disabled World (DW)
Is autism caused by too many dopamine receptors
No. The study found more dopamine D2 receptors in autistic participants but the researchers state clearly that the work does not explain why autism develops and cannot be used to make a diagnosis.
What is a PET scan and why was it used in this study
A PET scan, or positron emission tomography, is an imaging technique that shows biological activity in the brain. It was used here to measure dopamine receptors and glucose metabolism, and it was combined with functional MRI to study brain region communication.
Can this research be used to diagnose autism
No. The researchers emphasise that the findings describe biological variation associated with autism and are not intended as a diagnostic tool.
Why did the researchers study differences between autistic men and women
Autism has historically been studied more in men, so this was designed as the first PET study to also look at possible biological differences between autistic men and women, helping address a gap in earlier research.
What does glucose metabolism tell us about the brain
Glucose metabolism reflects how much energy different brain regions are using. Measuring it alongside dopamine and regional communication gives a fuller picture of how the brain functions in autistic and neurotypical people.
Does this study suggest autism and ADHD share a biological basis
It raises the question. Because dopamine is central to ADHD and around 40 percent of autistic people also have an ADHD diagnosis, the findings prompt further investigation into shared dopamine-related mechanisms.
How many people took part and were the groups balanced
The study included 60 adults, split evenly into 30 autistic and 30 neurotypical participants, allowing direct comparison between the two groups.
Insights, Analysis, and Developments
Editorial Note: What sets this work apart is its restraint - the team stops short of overclaiming, stressing that larger studies across different cohorts are still needed before the results can be treated as settled. For autistic adults and the clinicians who work with them, the value lies less in any single measurement than in the method itself, which shows that dopamine receptors, brain energy use, and regional communication can be studied together rather than in isolation. The finding that more dopamine receptors tracked with higher energy use in the same deep brain regions hints at a system working differently rather than simply being broken, and the researchers are clear that the goal is understanding neurodiversity and building better conditions in society, not changing autistic people. That framing, paired with the open question of why autism and ADHD so often travel together, is likely what will make this a reference point for future research.*
Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by University of Southern Denmark Faculty of Health Sciences and published on 21 Aug 2026, this content may have been edited for style, clarity, or brevity.
* Editorial additions by Ian C. Langtree.