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How time perception, executive functions and “time blindness” may play a role
When people think of ADHD, they often think first of difficulty concentrating or being unusually restless. In adults, however, ADHD can be much less obvious. Appointments are misjudged, tasks are repeatedly put off, belongings get misplaced or a thought disappears halfway through a conversation. Some people appear extremely organised from the outside while putting a great deal of effort into making sure that nothing slips through the cracks.
ADHD does not mean that attention is simply absent. The difficulty can be in directing it reliably towards what matters at a particular moment – and keeping it there when a task is boring, complicated or only becomes important at some point in the future.
Attention-deficit/hyperactivity disorder, or ADHD, is a neurodevelopmental disorder. Symptoms begin in childhood and may continue into adulthood. They centre around three areas: inattention, hyperactivity and impulsivity. How these features combine and how strongly they affect everyday life varies considerably from person to person.
Occasionally being distracted, forgetful or impatient is therefore not enough for an ADHD diagnosis. Symptoms need to have persisted over time, occur in more than one area of life and cause meaningful impairment. In adults, there must also be evidence that relevant symptoms were already present before the age of twelve.
ADHD can look very different from one person to another
Clinically, three presentations of ADHD are distinguished. For some people, inattention is the most prominent feature. They may regularly lose things, forget appointments, drift off during lengthy tasks or struggle to organise and complete their work. This presentation was previously often referred to informally as “ADD”.
For others, hyperactivity and impulsivity are more prominent. In adults, this does not necessarily mean constantly getting up or being visibly restless. It may instead feel like internal restlessness, a constant need to be doing something, difficulty waiting or a tendency to interrupt other people.
In the combined presentation, significant symptoms of both inattention and hyperactivity-impulsivity are present.
These presentations are not fixed for life. Physical hyperactivity in particular may become less obvious with age, while difficulties with attention, organisation or impulse control can remain.
Even two people with the same presentation may look very different in everyday life. One person may regularly forget appointments. Another may use three calendars, phone reminders and rigid routines precisely because they know appointments are otherwise easily forgotten. From the outside, the second person may look exceptionally organised. The amount of effort required to maintain that organisation is less visible.
ADHD is more than “being bad at concentrating”
Many difficulties in adulthood show up in situations that do not immediately look like an attention problem.
A bill may sit on a desk for two weeks even though paying it would take only a few minutes. A large task gets moved to tomorrow again and again. While tidying, three different jobs are started at once. During a conversation, an important thought appears, but by the time there is an opportunity to speak, it has disappeared.
Forgetfulness, difficulties with organisation and planning, frequently losing things, distractibility and trouble completing tasks can all be part of ADHD. Impulsivity may show up as making decisions very quickly, finding it difficult to wait or interrupting other people. Hyperactivity in adults is often experienced more as internal restlessness than obvious physical activity.
Emotional regulation can also be relevant in everyday life. Some adults with ADHD report becoming frustrated quickly or experiencing emotions very intensely. Difficulties with emotional regulation are not one of the core diagnostic symptoms in the same way as inattention, hyperactivity and impulsivity, but they are frequently described by adults with ADHD.
And there is another area that can have a considerable impact on everyday life while not immediately appearing to be related to ADHD: time.
When “later” is difficult to grasp
You know that an appointment starts at two o’clock in the afternoon. You can look at the clock and work out exactly how much time is left. And yet half past twelve may still feel like there is plenty of time. You start doing something else, and suddenly it is ten to two.
Experiences like these are often described using the term “time blindness.” The phrase captures the experience quite well, but it is not a separate medical diagnosis or an official diagnostic criterion for ADHD.
Research does, however, find differences in how people with ADHD process and estimate time. A meta-analysis published in twenty twenty-four found clear average differences in time-perception tasks across different age groups. Evidence specifically in adults is less consistent, but research also points to difficulties in areas such as time estimation and time management.
In everyday life, though, the important question is rarely whether someone can estimate five or ten seconds accurately. What matters is how an abstract point in time is translated into action.
An appointment at two o’clock does not really begin at two o’clock. Before then, you may need to finish what you are doing, find your documents, get changed, leave the house and travel for twenty minutes.
If those transition steps are regularly underestimated, someone can know perfectly well when an appointment begins and still leave too late.
A similar thing can happen with tasks. “That will take about an hour” may refer only to the main part of the task. Finding information beforehand, clarifying questions and checking the result afterwards may never have made it into the original estimate.
Suddenly two hours have passed, even though the task genuinely seemed like a one-hour job beforehand.
Planning is made up of many small mental steps
Meeting a deadline or arriving somewhere on time involves much more than knowing the date or looking at a clock. We have to estimate which steps are involved, how long each will take, when we need to begin and what else can realistically fit in beforehand.
This is where executive functions become relevant. The term describes a group of abilities that help us direct our behaviour towards a goal. They include temporarily holding information in mind, inhibiting impulses, switching between tasks and planning actions.
Research finds average differences in several of these areas in adults with ADHD, including working memory and inhibition. At the same time, there is considerable variation between individuals. There is no single executive-function profile that applies to everyone with ADHD.
This also helps explain why putting something in a calendar can be useful without solving every planning problem.
An entry saying “Submit tax documents by Friday” tells you when something has to be finished. It does not tell you that you first need to gather documents, download a missing statement, fill in a form and perhaps ask someone a question. Nor does it automatically tell you that Wednesday may actually be the right time to begin.
Tasks that are still far away can remain surprisingly abstract. As the deadline gets closer, the situation changes. Something that has been easy to postpone suddenly becomes immediate.
Many people experience this to some extent, with or without ADHD. In ADHD, however, the pattern can be particularly pronounced: something is postponed for days, yet shortly before the deadline it suddenly becomes much easier to work on.
That does not mean someone deliberately creates pressure. Immediate urgency can simply make it easier to direct attention and action towards one specific task.
Why this can look like a lack of motivation
Difficulty starting a task can be particularly hard for other people to understand. Someone wants to write an email, knows exactly what needs to go into it and still puts it off for hours or days. The same person may be able to spend a long time on another activity without apparent difficulty.
From the outside, that can seem contradictory.
In ADHD, attention is not simply weak all the time. Interesting, novel or immediately rewarding activities may hold attention very strongly, while monotonous tasks or those without immediate urgency can be much harder to begin.
The term “hyperfocus” is often used in everyday discussions of ADHD. It is not a core diagnostic feature and is not as clearly defined scientifically as social-media discussions can sometimes suggest. The experience it describes, however, is familiar to many people with ADHD: becoming so absorbed in an activity that the surroundings, other tasks and sometimes the passage of time fade into the background.
Being able to concentrate intensely on certain activities therefore does not rule out ADHD.
The more useful question is often how reliably attention can be directed and disengaged when circumstances require it.
Difficulties with time do not automatically mean ADHD
Many of the situations described here are not specific to ADHD. Almost everyone occasionally underestimates how long something will take, forgets something important or postpones an unpleasant task.
Persistent stress, lack of sleep, depression, anxiety disorders and other psychological or physical factors can also affect concentration, memory and planning.
An ADHD assessment therefore involves more than counting how many familiar characteristics someone recognises in themselves. Clinicians look at the overall pattern: When did the difficulties begin? Were they present in childhood? Do they occur in different areas of life? How much do they interfere with everyday functioning? And could something else explain them better?
An online questionnaire or social-media post can be a reason to look into the subject further. It cannot establish a diagnosis.
If difficulties with attention, organisation or impulsivity have been causing significant problems for a long time, a professional assessment may be useful.
A short exercise: How long does it actually take?
Over the next few days, choose three ordinary activities where you often misjudge the time involved.
It might be getting ready in the morning, leaving the house, completing a particular work task or preparing for an appointment.
Before you start, write down how long you expect it to take.
Then check the actual time afterwards.
What matters is not whether your estimate was five minutes out. Look at where the additional time appeared.
Perhaps the activity itself really does take twenty minutes, but another ten pass before you actually begin. Maybe the shower takes exactly as long as expected, while getting dressed, finding your keys and packing your bag were barely included in the estimate.
Or perhaps a work task takes only half an hour once everything is ready, but gathering the information needed takes another thirty minutes.
After a few observations, try planning from the necessary starting point rather than only from the deadline.
Instead of:
“I need to leave at eight.”
you might use:
“I start getting ready at half past seven.”
It sounds like a small change. For planning, it can make a significant difference.
Knowing when something needs to happen is not always the same as knowing when you need to start in order for it to happen on time.
Sources and further reading
National Institute of Mental Health (NIMH). Attention-Deficit/Hyperactivity Disorder: What You Need to Know. Information on ADHD symptoms and diagnosis in adults.
Centers for Disease Control and Prevention (CDC). Symptoms of ADHD. Overview of ADHD presentations and symptoms across the lifespan.
Association of the Scientific Medical Societies in Germany (AWMF) (2026). S3 Guideline: Attention-Deficit/Hyperactivity Disorder (ADHD) in Children, Adolescents and Adults.
Metcalfe, K. B., McFeaters, C. D. & Voyer, D. (2024). Time-Perception Deficits in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis. Developmental Neuropsychology, 49(1), 1–24. DOI: 10.1080/87565641.2023.2293712.
Mette, C. (2023). Time Perception in Adult ADHD: Findings from a Decade – A Review. International Journal of Environmental Research and Public Health, 20(4), 3098. DOI: 10.3390/ijerph20043098.
Boonstra, A. M., Oosterlaan, J., Sergeant, J. A. & Buitelaar, J. K. (2005). Executive functioning in adult ADHD: a meta-analytic review. Psychological Medicine, 35(8), 1097–1108. DOI: 10.1017/S003329170500499X.
