Do more diagnoses mean more cases? What the data on ADHD and autism can show — Photo: Adobe Stock
The proportion of 16 to 24 year olds with common mental disorders has increased significantly over the past three decades in the UK. In 1993, approximately one in six young people had these conditions. In 2024, the proportion reached one in four. At the same time, recorded diagnoses of autism and attention deficit hyperactivity disorder (ADHD) increased by more than 20 and six times, respectively, in certain age groups.
The data is part of an independent review into mental health, autism and ADHD, led by Professor Peter Fonagy, published last Friday (9). The report looks at the rise in mental health problems, changes in diagnoses and the challenges facing care services in the UK.
Among the main results and evaluations highlighted by experts are:
Increase in mental disorders: while problems related to anxiety, worry, depressive thoughts and panic have become more frequent among young people, irritability has decreased and conduct problems have remained stable.
Growth in autism and ADHD diagnoses: records increased, respectively, more than 20 times and more than six times in certain age groups. Experts point out that these conditions have historically been underdiagnosed, leaving many people without proper identification for years.
Excess or lack of diagnoses: researchers state that both situations can occur simultaneously. The growth in records does not necessarily mean that all people who need care are being identified.
Difficulty accessing treatment: data from the British National Audit Office indicates that only around a quarter of children with a probable mental health condition are able to access services funded by the National Health Service (NHS).
Risk of restricting care: experts warn that prioritizing only patients with more severe difficulties could leave autistic people or people with ADHD whose needs are less evident without assistance.
Artificial intelligence in mental health: digital tools can contribute to care, but should not replace healthcare professionals, especially in risk situations.
The review's main recommendation is a change in the way health, education and social care services deliver help. Instead of relying exclusively on formal diagnoses, the system should consider individual needs and allow people to receive support more quickly.
The proposal received positive evaluations from experts consulted by the Science Media Centre, an independent British organization that gathers scientific comments on topics of public interest. But the researchers emphasize that the change will depend on the expansion of services and the availability of qualified professionals.
Experts interviewed by g1 explain that the growth in records is related to factors such as greater awareness, changes in diagnostic criteria and identification of people who previously went unnoticed by health services.
Child and adolescent psychiatrist and professor of psychiatry at the University of São Paulo (USP) Guilherme Polanczyk states that there is an increase in diagnoses of mental disorders, including autism and ADHD, around the world. Some prevalence studies also suggest an increase in the number of people affected, but research in this regard is still more limited.
Child neurologist Felipe Kalil, professor at the PUC-RS School of Medicine and coordinator of the Child Neurology Service at Hospital Moinhos de Vento, adds that advances in the ability to identify these conditions help to explain part of the growth observed.
For experts, the central issue is not simply discovering whether there are too many or too few diagnoses, but understanding who actually presents these conditions, who is being correctly identified and how many people continue to lack access to the necessary follow-up.
Increase in mental disorders among young people is real, researchers say
One of the central points of the review is the finding that the growth in mental health problems among young people cannot be explained solely by people's greater willingness to talk about their symptoms.
The increase, however, did not occur uniformly across different symptoms and behaviors.
Problems related to worry, anxiety, depressive thoughts and panic have become more frequent. On the other hand, irritability decreased, while conduct problems remained stable.
A person may experience emotional distress without necessarily meeting the clinical criteria for a mental disorder. Likewise, someone may need support even without having received a formal diagnosis.
Autism and ADHD diagnoses grew more than 20-six times
Another highlight of the review is the significant growth in registered diagnoses of autism and ADHD.
In some groups, the number of registered diagnoses already approaches or exceeds estimates of the prevalence of these conditions in the population.
The scenario fuels discussions about the possibility of overdiagnosis. However, the researchers emphasize that the increase in registrations does not necessarily mean that more people are receiving incorrect diagnoses.
Polanczyk explained to g1 that, although the growth in diagnoses is evident, it is still unclear whether there has been a proportional increase in the number of people affected in the population.
“Today, when we make a diagnosis, we are doing it using other criteria that in fact include a number that includes people with milder abilities and difficulties than in the past”, he explains.
Therefore, comparing the increase in registered diagnoses with estimates considered stable can produce a mistaken interpretation about the existence of excessive diagnoses.
What has changed in the way autism and ADHD are diagnosed?
One of the main explanations for the increase in diagnoses is the transformation of the criteria used to recognize these conditions.
Polanczyk explains that, in the case of autism, an important change occurred in 2013, with the publication of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
Since this update, a broader understanding of autism spectrum disorder (ASD) has been adopted, including people with changes in communication and rigid or repetitive behavior patterns that present less intense manifestations.
In practice, this means that people who previously did not meet the criteria for receiving the diagnosis are now recognized within the spectrum.
"As we change the way we diagnose autism, it is difficult to compare today's rates with rates in the past. But, without a doubt, the number of diagnoses has increased," says Polanczyk.
The advancement of screening strategies, greater public awareness and increased access to health services also contributed to the identification of children and adolescents who could previously go years without a diagnosis.
This, however, does not completely exclude the possibility of a real increase in prevalence.
"It is possible that there is also some real increase related to genetic and environmental factors. Therefore, the observed growth in diagnoses probably reflects a combination of improved screening, greater access to health services and earlier recognition", adds Kalil.
Are there too many diagnoses or people without care?
Experts emphasize that excess and lack of diagnoses are not necessarily mutually exclusive situations. Both can occur simultaneously, even within the same health system.
In the case of autism and ADHD, the growth in records raises questions about the relationship between diagnoses and clinical needs. In conditions such as anxiety and depression, many people remain without identification and specialized assistance.
Polanczyk states that it is possible to find specific contexts in which diagnoses and treatments exceed prevalence estimates.
He cites studies carried out in the United States that identified rates of use of stimulant medications higher than the estimated prevalence of ADHD in certain groups.
These results may indicate situations of overdiagnosis or overtreatment. However, the psychiatrist emphasizes that this scenario does not necessarily represent the reality of the population as a whole.
In Brazil, for example, inequalities in access to specialized services are an important obstacle.
According to Polanczyk, estimates produced by his research group in São Paulo and Porto Alegre, around five years ago, showed that approximately 80% of adolescents diagnosed with a mental disorder did not receive treatment.
He also cites studies carried out in low- and middle-income countries in which the proportion of people without treatment varies between 60% and 80%. In some contexts, research has identified even higher percentages of people without diagnosis and without assistance.
The expert highlights that the perception of excess diagnoses is often associated with the reality of large cities and the exposure of the topic on social media.
In other regions, especially in the North and Northeast of Brazil, the lack of specialized services represents a much more evident problem.
For Polanczyk, although there may be an excess of diagnoses in certain groups or locations, the main concern in population terms continues to be the difficulty in accessing assistance.
More diagnoses also mean more access to benefits
Another factor pointed out by Polanczyk is the importance that diagnosis has become to guarantee rights and adaptations in different environments.
According to him, the formal recognition of autism or ADHD can facilitate access to treatments, school adaptations, specific conditions for taking tests and adjustments in the job market.
This contributed to increasing the demand for evaluations. The problem, according to the psychiatrist, is that many of these adaptations may be necessary even when the person does not meet all the criteria for a disorder.
However, the organization of the educational and judicial systems often conditions access to these resources on the presentation of a medical diagnosis.
Polanczyk explains that this requirement creates a situation where professionals may feel pressured to establish a diagnosis to ensure a person receives the support they need.
As a consequence, records may grow without this necessarily representing an equivalent increase in prevalence.
For the specialist, this is a tension that has not yet been resolved: how to guarantee care and adaptations for those who need it without turning psychiatric diagnosis into the only way of accessing these resources?
What are the risks of a mistaken diagnosis?
Increasing awareness about autism and ADHD can help identify people who need monitoring. But experts warn that recognizing signs is not the same as establishing a diagnosis.
Kalil explains that the assessment must consider well-established clinical criteria, the history of development and the impact of symptoms on the child's life. It is not enough to identify isolated behaviors or obtain a certain result in a screening questionnaire.
According to the neurologist, inadequate diagnoses can cause labeling, anxiety, unnecessary interventions and misinterpretations about the difficulties presented.
Polanczyk adds that, in the case of ADHD, an incorrect diagnosis can lead to the use of medication without an appropriate clinical indication.
Although the risks of stimulants are considered low when there is adequate indication, any medication can cause unwanted effects. For people who do not have the disorder, these risks may not be outweighed by benefits.
The psychiatrist also draws attention to the consequences of unnecessary psychotherapeutic interventions, which can require time and financial resources.
In the public network, the use of specialized services by people who do not need them can also reduce the availability of care for other patients.
There are also possible impacts on the way children and adolescents come to understand their own identity following a mistaken diagnosis.
“The objective should not be to diagnose more or less, but to suspect and diagnose better: to recognize early who needs monitoring, without transforming normal developmental difficulties into disorders”, says Kalil.
Late diagnosis can also have consequences
If overdiagnosis poses a risk, failing to identify people who actually have autism or ADHD can also cause significant harm.
According to Kalil, late diagnosis can prolong difficulties in learning, communication, behavior, social interaction and self-esteem.
In children and adolescents, these difficulties can increase emotional suffering and compromise school and family life.
Polanczyk highlights that there is consolidated evidence on the benefits of early interventions, especially in autism.
This occurs because certain phases of brain development present greater plasticity, favoring the response to environmental stimuli and therapeutic interventions.
The psychiatrist explains that this period can be especially important for the development of language and social skills.
In the case of ADHD, the relationship between early treatment initiation and better results is more complex, because the conditions identified the earliest are often also the most serious.
Even so, the specialist emphasizes that the lack of follow-up can allow difficulties to accumulate throughout life. He also cites evidence of increased risk of depression and suicide among people who receive late diagnoses.
The vice-president of the National Association for the Inclusion of Autistic People (Autistas Brasil) and researcher on misinformation about autism in Latin America Arthur Ataide adds that many people reach adulthood carrying a history of misunderstanding.
Children were considered inattentive, undisciplined, strange, lazy, disinterested or not very hardworking. Some learned, for years, that they needed to hide certain characteristics to get a partner.
