Autism and ADHD Symptoms: Are They Really Rising?

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• 📈 Autism and ADHD diagnoses have risen sharply, but symptom levels remain mostly stable.
• 🧪 A Swedish twin study found no significant increase in autism symptoms over a 9-year period.
• ⚖️ Experts suggest expanding diagnoses stem from changes in perception, not prevalence.
• 👧 ADHD symptoms showed a slight increase in girls, possibly due to improved recognition.
• 📚 Educational pressures and expanded criteria may be accelerating the rate of diagnoses.

Are Autism and ADHD Symptoms Really Increasing?

Autism and ADHD diagnoses in teens and young adults have gone up a lot in recent decades. But we need to ask: Are these conditions actually more common, or are we just better at finding them now? A big Swedish study looked at nearly 10,000 18-year-olds for nine years. It gave surprising information. Diagnoses might be going up, but main autism and ADHD symptoms stayed about the same. This odd finding shows that bigger changes in society, how we diagnose things, and culture could be making it seem like more people have these conditions.

Understanding Autism and ADHD Symptoms

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are conditions that start when the brain is developing. They can happen together, but they are different conditions. Each one affects learning, behavior, and how people interact with others in its own way. Knowing what autism symptoms and ADHD symptoms are helps us understand changes in diagnosis rates.

Autism Symptoms: Social Communication and Behavioral Patterns

Autism symptoms mainly fit into two groups:

1. Social Communication and Interaction Difficulties:
   • Trouble understanding body language, like eye contact, facial expressions, or how someone’s voice sounds.
   • It is hard to make and keep friends.
   • They struggle with back-and-forth talks or seeing things from another person’s view.
2. Restricted and Repetitive Behaviors/Interests:
   • They might do the same movements over and over, like hand-flapping or rocking.
   • They may focus very deeply on certain topics or things they like.
   • They really need routines and do not like changes or surprises.

These symptoms usually appear early on. But some people, especially those with milder autism, might show them in less obvious ways. People now know autism is a spectrum. This means different people have different levels and kinds of symptoms.

ADHD Symptoms: Inattention, Impulsivity, and Hyperactivity

ADHD symptoms fall into two main areas:

1. Inattention:
   • They often make careless mistakes or do not pay close attention to details.
   • It is hard for them to keep focus on tasks or during play.
   • They get easily distracted or forget things often in daily life.
2. Hyperactivity-Impulsivity:
   • They fidget or squirm a lot.
   • They talk too much or blurt out answers.
   • It is hard for them to wait their turn or to not interrupt others.

Some people show symptoms mostly in one area. For example, young children often show more hyperactivity. But others might have a mix of symptoms. Doctors usually see these symptoms before age 12. And they must cause big problems in many parts of life, like at home and school.

Diagnosing: A Complex Intersection of Biology and Society

Diagnosis is not just about checking boxes. It means looking at how much symptoms get in the way of a person doing well. This is often up to how we see things. Environment, culture, and what society expects all play a part. For example, some behaviors that cause problems in today’s classrooms might not have seemed bad in schools many years ago when things were more open.

Also, gender can change how symptoms show up. Girls often hide their problems. This can mean doctors find their autism or inattentive ADHD later, or not at all. Finding these conditions early and correctly means we must understand the many ways they appear in different people.

What the Swedish Twin Study Found

Researchers wanted to see if autism and ADHD symptoms were going up. So, they did a study over time with a large group of Swedish twins. Their aim was to separate the rise in official diagnoses from any real changes in how common symptoms were.

Study Design and Methodology

• Sample Size: 9,926 twins born between 1993 and 2001.
• Age Evaluated: All participants were evaluated at age 18.
• Data Collection: Parents completed standardized questionnaires:
  • Autism-related behaviors were assessed using 12 items based on established diagnostic criteria.
  • ADHD symptoms were evaluated using a 17-item parental report checklist, primarily focusing on inattention.

This way of setting up the study made sure things were consistent over the whole time. It also let researchers account for genetic and environmental factors always present in twin studies.

Main Findings

Published in Psychiatry Research, the study results give important information:

• 🧩 No increase over time in autism symptoms was found in either boys or girls.
• ⚖️ ADHD symptoms in boys remained stable, while girls showed a small but statistically significant rise.
• 📊 The share of individuals with high symptom scores (top 5–10%) did not expand over the years.

Even with symptom levels staying the same, doctors gave many more autism and ADHD diagnoses to the wider public during this period. This shows a growing gap between actual behaviors and the medical names given to them.

Diagnoses vs. Symptoms: Bridging the Gap

This difference between how many diagnoses are made and how common symptoms are shows an important idea: we might be diagnosing more people, but this does not mean more people actually have symptoms.

Diagnoses as Social Constructs

There are no clear biological tests for autism and ADHD, unlike conditions like diabetes. Instead, doctors diagnose them by watching behaviors and getting reports from people themselves or their caregivers. So, what counts as a condition that can be diagnosed can change over time. This depends on:

• Cultural attitudes toward mental health
• Medical training and screening protocols
• Changes in diagnostic criteria (e.g., DSM revisions)
• Public awareness and acceptance

More diagnoses might show better detection, easier access to care, and changing views in society. This could be the case instead of a true sudden rise in these brain development conditions.

Functional Impairment: The Moving Target

A key part of diagnosis is impairment. This means how much the symptoms get in the way of daily life. But what counts as impairment can change. A child who has trouble focusing in a demanding school might not have been seen as having problems in a school setting that focused more on play.

What does this mean? Society’s rules for behavior might be quietly playing a big part in the rise of diagnoses.

What’s Fueling the Diagnoses Spike?

The quick rise in autism and ADHD diagnoses is not happening by itself. Many things work together to cause this trend. They change who gets diagnosed and at what age.

Increased Awareness and Advocacy

People know much more about these conditions now. This is because neurodivergent people and groups have spoken up a lot. The shame often tied to diagnoses has gone down. This makes parents and adults feel better about getting checked.

• Parents are often more educated about early signs.
• Teachers are quicker to flag potential concerns.
• Physicians are now trained to recognize a broader range of presentations.

Because of this, more children and also more adults are getting identified. This is especially true for those who might have been missed before.

Evolving Diagnostic Criteria

With each new version of the DSM (Diagnostic and Statistical Manual of Mental Disorders), the rules for diagnosing autism and ADHD have changed:

• DSM-5 (2013) revised ASD to include previously separate conditions (like Asperger’s and PDD-NOS) under one “spectrum.”
• ADHD rules were updated. They now fit adults better and cover both inattentive and combined types.

These changes made it so more people could get a diagnosis. They also helped doctors spot symptoms in many ways across all ages.

Educational and Social System Incentives

Official diagnoses give people access to important help:

• Special education services and classroom accommodations.
• Medication prescriptions and therapeutic interventions.
• Standardized test modifications and extra time.

In a system that asks more and more for good thinking and emotional skills, there is a clear reason to seek labels. These labels let people get resources.

Also, behaviors once called “quirky” or “odd” might now get a closer medical look. This is especially true in places that care a lot about standard rules and tests.

Shifting Interpretations of Impairment

As social settings get harder—with social media, quicker talks, and more school pressure—the usual rules for how people should act get stricter. This makes people with different ways of thinking or behaving seem more impaired.

The main author, Olof Arvidsson, saw this cultural effect during the study. He said, “Parents today may understand behaviors differently than they would have ten years ago” (Arvidsson et al., 2025).

The ADHD Gender Gap

One of the study’s key findings was a small but important rise in ADHD symptoms among 18-year-old girls.

Historical Underdiagnosis of Girls

For a long time, people thought of ADHD as outer behaviors like being very active and impulsive. These are traits more often seen in boys. But girls often show:

• Inattentiveness
• Daydreaming
• Internalized distress
• Organizational difficulties

As studies have changed, it is now clear that doctors often missed girls’ symptoms for a long time. This meant fewer diagnoses for girls. But more awareness and better ways to check for ADHD in girls are closing that gap.

Rising Mental Health Needs in Teen Girls

More reports of ADHD symptoms might also be tied to mental health trends:

• Adolescent girls are experiencing rising rates of anxiety and depression.
• These conditions often overlap with or mask ADHD.

Doctors are getting better at telling these overlapping conditions apart. This could be one reason for the slight rise in ADHD symptom reports in females.

Challenges for Healthcare and Education

The increase in autism and ADHD diagnoses affects how health care and schools give out help and resources.

Benefits of Early Identification

• It makes early help possible, which leads to better results.
• It lessens the frustration for families trying to understand behaviors.
• It opens up support services in schools and therapy.

Potential Downsides

• Too many diagnoses might spread resources too thin. This makes it harder for people with greater needs to get help.
• Professionals feel pressured to diagnose quickly because systems are too busy. This can lead to quick, not very deep, checks.
• School support systems more and more need an official diagnosis to pay for personal education plans. This pushes families to get a doctor’s check, even if symptoms are not severe.

A careful approach that considers the full situation, ideally with different experts looking at it, helps make sure diagnoses are helpful and truly mean something.

The Role of Culture in Defining Disorder

What one culture or place sees as a symptom might not be seen that way in another. Our ways of grouping conditions partly show what our culture values and expects.

Cultural Expectations Shape Behavior Interpretation

Western cultures often stress doing well alone, doing many things at once, and being outgoing. These traits might not fit people with autism or ADHD well. But in other cultures that put group harmony or watching above all else, these same behaviors might not seem like problems.

This shows an important point: more diagnoses might be tied more to changing cultural standards than to a real rise in how often these conditions occur.

Avoiding False Alarms

The study shows symptoms haven’t gone up much, especially for autism. But it is important not to wrongly think this means diagnoses are wrong or overblown.

Diagnoses Still Matter

• They confirm what a person is going through and their difficulties.
• They make it easier to get specific help and adjustments.
• They help people get a deeper understanding of themselves or their children.

But calling everyone with similar behaviors “disordered” risks turning natural human differences into medical problems.

The main thing is to find a balance between accepting differences and being specific.

Rethinking the Path Forward

Going forward, researchers, doctors, teachers, and families can change how we see and handle brain development conditions like ADHD and ASD.

Suggestions for Future Practice

• ✅ Do more research across different groups of people, especially those who are often overlooked.
• ✅ Improve tools to tell ADHD in girls apart from other things, and autism in adults who do well in daily life.
• ✅ Focus on training doctors to do full assessments, looking at the whole person.
• ✅ Move away from general diagnostic checklists and towards understanding people in their specific situations.
• ✅ Give individuals and families more power through education that values different brain types.

Diagnoses are going up. This might be because of society’s rules, better ways to spot issues, or reasons tied to how systems are set up. But one thing is clear: people’s brains have always varied a lot. The more we look at autism and ADHD symptoms from all angles—from how we diagnose them to how we help people—the better we can serve those who live in their own special and real ways.

Citations:

Arvidsson, O., Brikell, I., Larsson, H., Lichtenstein, P., Kuja-Halkola, R., Johnson, M., Gillberg, C., & Lundström, S. (2025). ASD and ADHD symptoms in 18-year-olds – A population-based study of twins born 1993 to 2001. Psychiatry Research, 333, 116613. https://doi.org/10.1016/j.psychres.2025.116613