ADHD in adults: lesser-known symptoms, late diagnosis, and effective treatment

In this article, neuropsychologist Ana Utrilla Lack discusses the most important aspects of attention-deficit/hyperactivity disorder (ADHD) in adults.

Introduction

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder, which means its symptoms must have begun before age 12. However, it often goes undetected and undiagnosed in childhood. That’s why, in neuropsychology practice, it’s common to see adult patients with significant difficulties with organization and planning, as well as problems at work, in social relationships, and with their partners. When assessed, these patients are diagnosed with attention-deficit disorder with or without hyperactivity.

What is ADHD?

According to the DSM-5 (APA, 2013), attention-deficit disorder is defined as a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development. 

According to the DSM-5 (APA, 2013), attention-deficit/hyperactivity disorder (ADHD) is characterized by a set of behaviors related to difficulties with attention, impulsivity, and/or restlessness that persist over time and at different stages of a person’s life. 

These difficulties can affect how people organize themselves, concentrate, or stay calm, and can affect areas such as work, school, or personal relationships. Because it is a neurodevelopmental disorder, its symptoms must have begun before age 12.

Sometimes it isn’t diagnosed in childhood because the parents may have similar undiagnosed symptoms or because the family’s structure and support help the child function well, among other factors.

However, it often goes undiagnosed in childhood for a variety of reasons, including:

1. The normalization of symptoms or their misattribution to other factors, such as personality traits or normal stages of development.
2. Limited access to healthcare professionals trained to make the diagnosis at an early stage.
3. Compensation by the family or social environment, which masks the difficulties and delays diagnosis.
4. The presence of comorbidities that can mask the disorder, such as anxiety, learning, or mood disorders.
5. Family members’ reluctance to accept a diagnosis, since it is often still a “taboo” subject. 

The concept of ADHD

The concept and characterization of ADHD have changed significantly over time. It first appeared in psychiatric diagnostic manuals in the DSM-III in 1980, which introduced the term “attention-deficit disorder, residual type” to describe ADHD symptoms that persisted into adulthood after a childhood diagnosis. This concept was removed in the 1987 revised version (DSM-III-R), but it continued to be used informally in clinical practice to refer to adults with persistent symptoms.

Later, in 2000, the DSM-IV recognized that ADHD could be diagnosed in adults, provided there was evidence that the symptoms had begun in childhood.

Finally, in 2013, with the publication of the DSM-5, it was confirmed that ADHD can continue into adulthood. The diagnostic criteria were adjusted to allow diagnosis with five (instead of six) symptoms in people over 17. The concept of “residual” was also formally removed, since ADHD is considered a disorder that can persist throughout life without needing that label.

ADHD in adults

Attention-deficit/hyperactivity disorder (ADHD) in adults is characterized by difficulties with attention, impulsivity, and hyperactivity that persist beyond childhood, affecting daily functioning and quality of life. As in children with ADHD, various areas are affected in adults, such as interpersonal relationships and professional and academic life (Sapkale & Sawal, 2023).

ADHD affects both men and women, although there are differences in how it presents and is diagnosed. It is more likely to be identified in boys and men because they tend to have more visible symptoms related to hyperactivity. Women, on the other hand, tend to show mainly inattentive symptoms and greater emotional instability, which can make it harder to recognize early.

Lesser-known symptoms of ADHD in adults

When people talk about ADHD, stereotypes often come to mind, such as a restless child or one who doesn’t pay attention in class. That’s why it can sometimes be hard to picture how this disorder shows up in adulthood.

As mentioned, ADHD symptoms are related to attention difficulties and/or impulsivity and hyperactivity. However, because of the demands of adult life and the tools a person has acquired over time, symptoms and behaviors can look very different from those seen in childhood.

For this reason, many signs of ADHD in adulthood often go unnoticed, are misinterpreted, or are even attributed to a lack of motivation, stress, or personality traits.

Below are some symptoms that may be present in adults with ADHD and are often not associated with this diagnosis:

1. Difficulty starting tasks

It’s common for a person with ADHD to see themselves as a procrastinator: even though they know an activity is important, and may even be interested in it, they find it very hard to get started and don’t begin until time is running out and the pressure is on, finding in that stress the push they need to finally start.

This paralysis or feeling of being “frozen” and unable to start tasks isn’t due to a lack of willpower or discipline; it’s related to impaired executive functions, which are linked to the frontal cortex and are responsible for planning, organizing, and initiating goal-directed behavior.

2. Frequently forgetting small or everyday tasks

It doesn’t matter how regularly these tasks need to be done. It’s common to forget things like paying the electric bill, locking the door, or picking something up on the way home, which then causes a lot of guilt and frustration for the person and those around them. These lapses are due to working memory difficulties that make it hard to keep these tasks in mind while doing other activities.

3. Problems managing time

Believing there’s enough time to get somewhere or to finish everything before leaving can be a common behavior in people with ADHD. This can lead them to be late regularly or, on the contrary, to arrive far too early to compensate, because of the stress the possibility of being late causes them.

4. A tendency to hyperfocus

At the opposite end of the constant inattention many people with ADHD experience is hyperfocus. This involves periods of extreme concentration on highly stimulating tasks, during which people can even lose track of time and neglect other important responsibilities.

5. Low self-esteem or feelings of inadequacy

As a result of the symptoms described above, people with ADHD often develop negative self-talk, convincing themselves that they are lazy, disorganized, or incapable. This significantly affects their self-esteem and self-concept.

Although inattention is often one of the most visible symptoms in adults with ADHD, we shouldn’t forget that hyperactivity can also be present in many cases. However, it doesn’t show up the same way as in childhood. Instead of constant or obvious physical activity, hyperactivity in adults tends to be more internal or subtle, which can make it harder to identify.

Below are some of these signs that, because they are less well known, often go unnoticed or are wrongly attributed to anxiety, stress, or simply a “restless nature.” These are some common symptoms, although keep in mind that they can vary, since each person has a unique profile.

1. A constant feeling of inner restlessness

Even when sitting down and apparently calm, the person may be feeling a strong need to do something. This mental restlessness often translates into anxiety, impatience, or difficulty relaxing.

2. Talking fast or interrupting often

Some people with ADHD may be seen as talking a lot, changing topics quickly, or tending to interrupt in conversations, without meaning any harm, simply because they feel an urgent need to say what they’re thinking before they forget it.

3. Difficulty being at rest or enjoying downtime

People with ADHD often say they find it hard to “do nothing” or to do things like sit down to watch a movie or rest, and they may even feel uncomfortable and frustrated.

4. Constant subtle movement

Fidgeting with their fingers, moving their legs, changing position often, or even getting up to do something for no apparent reason.

5. Constantly seeking activities or stimulation

Changing interests often, starting many projects without finishing them, or having a very packed schedule can be a way of managing the need to stay stimulated and avoid boredom.

6. Difficulty waiting

Low tolerance for waiting in line, sitting in traffic, or waiting for others to finish talking. This isn’t due to bad manners but to a real sense of urgency that is hard to control.

7. A tendency to multitask

Although it isn’t always effective, many adults with ADHD try to do several things at once as a way to stay busy or avoid the frustration of a single long task.

Neuropsychological assessment of ADHD in adults

Today, there is more access to information about ADHD and its symptoms, which, on the one hand, supports timely diagnosis but, on the other, oversimplifies what this disorder involves and can lead to overdiagnosis. That’s why, if someone suspects they have symptoms of this disorder, they should see the right professional for the necessary assessment to confirm or rule out that suspicion.

As neuropsychologists, our assessment starts with a clinical interview. Its goal is to understand the behaviors or symptoms that suggest the diagnosis, and a key part is determining when they began, since, as mentioned above, even though the disorder continues into adulthood, the symptoms must have begun at an early stage because it is a neurodevelopmental disorder.

We also want to understand the current impact of these symptoms to determine whether they are clinically significant, that is, whether they are affecting different areas of the patient’s life. A differential diagnosis is also necessary to make sure the symptoms aren’t caused by another disorder, such as anxiety or depression.

Based on the information gathered in the interview, diagnosis requires neuropsychological testing to assess the patient’s performance on tasks mainly related to executive functions, as well as other cognitive functions such as memory, language, and attention.

The choice of tests may vary depending on the patient and their characteristics; what matters is being clear about the goal and making sure the tests used are aligned with it. 

Some of the tests proposed by the Cantabria ADHD Support Foundation (CADAH) (n.d.) for the neuropsychological assessment of ADHD in adults are:

1. Stimulus-tracking tests, such as the Trail Making Test (Reitan, 1958)

These tests are designed to assess executive functions: 

The Trail Making Test, in its B form, assesses the patient’s attention and planning skills. The patient is asked to draw a path connecting numbers in ascending order, or alternating numbers and letters (1-A-2-B…) in sequence. Although it seems like a simple task, it can be a major challenge for people who have difficulty directing their attention or coming up with strategies.

This test requires sustained concentration while switching between different types of information, which gives us valuable data on the patient’s ability to plan, sustain attention, and shift focus as the task requires.

2. Planning tasks, such as the Tower of Hanoi or the Zoo Map, part of the BADS test (Wilson et al., 1996)

As part of the assessment, planning tasks are also used, such as the Tower of Hanoi, which requires coming up with a strategy to solve a specific problem while following a set of rules established at the start.

Another useful test is the Zoo Map, which I personally find very representative of everyday situations. In this task, the person is asked to plan a route through a zoo while meeting certain conditions, which involves planning, prioritizing, and anticipating the steps to follow.

This type of exercise allows us to observe how the person structures their thinking and carries out a logical sequence of actions toward a goal.

3. Interference tasks, such as the Stroop Color and Word Test (Golden, C.J.)

Another commonly used test is the Stroop Color and Word Test, an interference task that makes it possible to assess processes such as selective attention and the inhibition of automatic responses. In this test, the patient is shown a list of color words (such as “red” or “green”) printed in a color different from the one they name. For example, the word “blue” printed in yellow. The task is to name the color of the ink rather than read the word.

Although it seems simple, it takes considerable effort to inhibit automatic reading and focus on the instruction given, which can be a major challenge for people with difficulties in inhibitory control or managing impulsivity.

We can also use more comprehensive test batteries, such as the Neuropsychological Battery of Executive Functions (BANFE-3), developed by Ostrosky.

Assessing ADHD in adults requires combining different tools, including the neuropsychological tests mentioned above. To obtain an accurate, complete diagnosis, self-report scales and structured interviews such as the DIVA-5 can also be used.

This combination makes it possible to identify the patient’s specific difficulties and guide an appropriate intervention plan. The DIVA-5 interview, based on DSM-5 criteria, explores the presence of the symptoms of the diagnosis, as well as their intensity and impact on the person’s life.

Effective treatments and strategies for adults with ADHD

Once a diagnosis of ADHD in adults has been made, the next step is treatment, which should be multidisciplinary. In some cases, this includes medication prescribed by a psychiatrist, mainly to improve attention and reduce impulsivity. However, medication should be combined with neuropsychological intervention, in which, at the start, the specific goals the patient wants to achieve are set together with them, based on their needs and their personal, social, and work activities.

As part of neuropsychological intervention, specialized digital platforms such as NeuronUP can be used. NeuronUP offers personalized exercises to stimulate various cognitive functions, helping improve attention, memory, and executive functions in a structured way tailored to each patient.

Digital tools can also be very helpful in daily life. There are apps such as Todoist or Trello that make it easier to organize and manage tasks, and others such as Headspace that support mindfulness practice and stress reduction, both key aspects of comprehensive ADHD management.

As mentioned above, ADHD can be accompanied by emotional symptoms such as anxiety or depression, as well as frequent feelings of frustration and low self-esteem, which, if not properly addressed, can interfere with treatment. In this regard, practices such as mindfulness have proven useful, since they help improve emotional regulation, reduce stress, and encourage greater awareness of the present moment. Incorporating these tools can be a valuable complementary strategy in the comprehensive approach to ADHD in adults (Crespo & Valero, 2019).

Conclusion

Although ADHD is usually associated mainly with difficulties, it’s also important to recognize the strengths that can come with this diagnosis. Many people with ADHD stand out for their creativity, divergent thinking, energy, and enthusiasm, as well as great resilience in the face of challenges. Their tendency to seek new experiences and their ability to hyperfocus on topics that interest them can be valuable advantages at work and in their personal lives. Recognizing these qualities helps build a more complete, positive view, boosting self-esteem and a balanced approach to the disorder.

Detecting ADHD in adults early is key so that people understand what is happening to them and can seek the help they need. People often develop compensatory strategies that help them manage everyday difficulties. However, these strategies don’t always prevent their personal, work, and social lives from being affected, especially when the symptoms aren’t clearly identified. That’s why a well-made diagnosis, together with comprehensive treatment tailored to each case, can make a big difference.

Once the diagnosis has been made, the next step is to start appropriate treatment. The neuropsychologist plays a key role in designing an individualized intervention plan that meets the patient’s specific needs. This plan should address both behavioral and emotional aspects, aiming to improve quality of life and emotional stability.

It’s also important to promote an open, informed attitude toward neurodivergence. Although there is greater awareness of ADHD today, stigmas and misconceptions still persist that can limit personal and work opportunities for those who live with it, also affecting their self-esteem. As a society, we can help create a more understanding environment by being careful with our words and how we talk about ADHD, recognizing that the difficulties people with this diagnosis face go beyond willpower.

As a professional, I believe that understanding ADHD beyond its difficulties allows us to better support those who live with it and give them the support they really need to build on their strengths and improve their quality of life.

References

• American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Author.
• Crespo, M., & Valero, S. (2019). Mindfulness y autorregulación emocional en adultos con TDAH: una revisión sistemática. Revista de Psicología Clínica con Niños y Adolescentes, 6(1), 41-46.
• Fundación CADAH. (s.f.). TDAH: Instrumentos o pruebas para evaluar las funciones neuropsicológicas y ejecutivas (Parte II). Recuperado de https://www.fundacioncadah.org/web/articulo/tdah-instrumentos-o-pruebas-para-evaluar-las-funciones-neuropsicologicas-y-ejecutivas-parte-ii.html
• Golden, C. J. (n.d.). Stroop Color and Word Test. [Manual].
• NeuronUP. (n.d.). Cognitive rehabilitation platform. Retrieved from https://www.neuronup.com
• Ostrosky, F. (año). Batería Neuropsicológica de Funciones Ejecutivas (BANFE-3). [Manual].
• Reitan, R. M. (1958). Validity of the Trail Making Test as an indicator of organic brain damage. Perceptual and Motor Skills, 8(3), 271–276.
• Sapkale, N., & Sawal, M. (2023). ADHD in adults: An overview of symptoms, diagnosis, and management. Journal of Psychiatry and Neuroscience, 48(1), 10-20. https://doi.org
• Wilson, B., Alderman, N., Burgess, P., Emslie, H., & Evans, J. J. (1996). Behavioural Assessment of the Dysexecutive Syndrome (BADS). Thames Valley Test Company.

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“This article has been translated. Link to the original article in Spanish:”
ADHD en adultos: síntomas poco conocidos, diagnóstico tardío y tratamiento eficaz