ADHD symptoms and signs of ADD in adults

Written and professionally reviewed by Felix Enghoff Klich, authorised psychologist
Last updated: October 2026

ADHD can show in many different ways. In adults, the symptoms are not necessarily about obvious hyperactivity or not being able to sit still. For many, ADHD shows rather as concentration difficulties, racing thoughts, inner restlessness, forgetfulness or difficulty creating structure and overview in everyday life.

The symptoms can also change over a lifetime. Some have had clear difficulties since childhood, while others only really struggle as adults, when demands from work, education, family life and planning increase. ADHD is a neurodevelopmental condition in which the symptoms begin in childhood, even though the diagnosis may only be made much later.

What are the typical symptoms of ADHD?

ADHD is particularly associated with symptoms of inattention, hyperactivity and impulsivity. How much each area dominates varies from person to person. Some mainly experience difficulties with attention, while others also have clear hyperactivity and impulsivity.

In adults, ADHD can show, among other things, as:

• difficulty maintaining concentration
• being easily distracted
• forgetfulness and a tendency to lose things
• problems with planning, structure and time management
• difficulty getting started on or finishing tasks
• a tendency to put off tasks
• inner or physical restlessness
• impulsive actions or decisions
• difficulty waiting or holding back
• problems keeping track when there are many simultaneous demands

It is common to experience some of these difficulties without having ADHD. In ADHD, it is a more persistent pattern that affects the person's functioning in everyday life across relevant contexts.

Inattention and concentration difficulties

Attention difficulties are among the most central symptoms of ADHD. It can, for example, be hard to maintain concentration during long conversations, meetings, reading or tasks that feel monotonous.

Some find that their attention depends heavily on interest and stimulation. An exciting task can be considerably easier to immerse yourself in than a routine or administrative one.

The difficulties can also show as jumping between tasks, overlooking details or starting many things without finishing them. In adults, the CDC describes, among other things, difficulties directing attention, completing longer tasks and staying organised.

Planning, structure and time management

ADHD symptoms are not only about concentration. Many adults experience significant challenges organising everyday life.

It can, for example, be hard to estimate how long a task will take, prioritise between several tasks or keep track of appointments and deadlines. Some therefore become very dependent on calendars, reminders and lists to make everyday life work.

Others experience repeated periods where tasks are put off until the time pressure becomes so great that it becomes easier to get started.

From the outside, this can look like a lack of motivation or structure, but in ADHD such difficulties can be part of the overall symptom picture.

Hyperactivity in adults can be inner restlessness

Hyperactivity does not necessarily look the same in adults as in children. The obvious motor activity can become less prominent with age, while some adults experience inner restlessness or agitation to a greater degree.

This can, for example, feel like a need to be busy all the time, difficulty relaxing or a sense of constant mental activity.

Others continue to have more visible signs of hyperactivity and may, for example, find it hard to sit still, move their hands or feet a lot, talk a lot or have a high activity level.

Impulsivity in ADHD

Impulsivity can show, among other things, in acting or speaking quickly without first considering the consequences.

It can, for example, be hard to wait your turn in a conversation, and you may end up interrupting others. In some, impulsivity can also affect decisions, finances or other areas of everyday life. NICE describes impulsivity, among other things, as actions and decisions taken quickly without sufficient consideration of the long-term consequences.

What are ADD symptoms?

The term ADD is still often used in everyday language about people in whom attention difficulties are prominent, while hyperactivity and impulsivity play a smaller role.

You can therefore experience significant ADHD-related difficulties without appearing particularly physically restless.

Typical difficulties can include concentration problems, forgetfulness, daydreaming, problems with organisation and planning, and difficulty getting started on and finishing tasks.

In the current diagnostic understanding, this is regarded as a presentation of ADHD rather than a separate diagnosis. Read more about the difference between ADD and ADHD.

Emotional symptoms in ADHD

ADHD is not only about attention and restlessness. Many adults also find that emotions come quickly and strongly, and that it is hard to calm down again. This is often called emotional dysregulation. It is not a separate diagnostic criterion, but it is frequently described in adults with ADHD.

It can, for example, show as:

• a short fuse and irritability
• strong reactions to criticism or rejection
• rapid mood changes during the day
• frustration when things do not go as planned
• difficulty letting go of a disappointment or conflict

For some, it is precisely the emotional reactions that take up the most space in relationships, friendships and at work.

ADHD symptoms in women

ADHD is often detected later in girls and women. The symptoms can be less visible and more often show as inner restlessness, racing thoughts, forgetfulness and problems keeping track of everyday life than as obvious physical hyperactivity.

Many women have for many years compensated with perfectionism, lists and extra effort. The difficulties may therefore be explained as stress, anxiety or sensitivity before anyone considers ADHD. Hormonal changes, e.g. around menstruation, pregnancy and menopause, can make the symptoms fluctuate for some.

How ADHD can affect everyday life

The symptoms only become significant when they affect the way you function. In adults, this can typically be seen in these areas:

• Work and education: missed deadlines, many unfinished tasks and a feeling of performing below your level
• Finances and practical tasks: forgotten bills, reminders, impulse purchases and unopened post
• Relationships: forgotten appointments, interruptions and conflicts about sharing tasks at home
• Sleep and energy: difficulty falling asleep because your thoughts are racing, and tiredness during the day
• Self-esteem: many years of feeling that you are not good enough, even though you try hard

ADHD rarely occurs alone

Many adults with ADHD also have anxiety, depression, sleep problems or autism. The symptoms can resemble and affect each other, which can make ADHD harder to spot. Read more about ADHD, anxiety and depression and about AuDHD, when ADHD and autism occur together.

ADHD can look different from person to person

There is no single way of having ADHD. Two people with ADHD can experience quite different challenges.

The symptoms can also change throughout life. Some experience less visible hyperactivity as adults, for example, while difficulties with concentration, organisation and inner restlessness can remain prominent.

At the same time, the surroundings affect how apparent the difficulties become. A person can function well in one context but experience significant problems when demands for independent planning, structure or sustained attention increase.

When can ADHD symptoms be a reason for assessment?

Recognising individual ADHD symptoms does not necessarily mean that you have ADHD. Concentration difficulties, restlessness and problems keeping track can also occur with, for example, stress, sleep problems, anxiety, depression and other mental or physical conditions.

In an ADHD assessment, one therefore looks not only at which symptoms are present, but also at their development throughout life, whether they have been present since childhood, how they affect the person's functioning, and whether the symptoms are better explained by other factors. An ADHD diagnosis should not be made solely on the basis of a questionnaire or a self-test.

If you have experienced symptoms of ADHD over a long period that affect, for example, work, education, relationships or your everyday life, a professional assessment may be relevant. You can get a first indication with the ASRS self-test for ADHD.

An assessment typically includes a structured interview such as DIVA-5, where the symptoms are reviewed in both adulthood and childhood. If the assessment shows ADHD, treatment may consist of psychoeducation, psychotherapy and possibly medical treatment of ADHD.

At Nordisk Psykiatri we offer assessment for ADHD and ADD for adults in Copenhagen.

Frequently asked questions about ADHD symptoms in adults

What are the first signs of ADHD in adults?

Many first describe problems with concentration, forgetfulness, putting off tasks and difficulty keeping track of time and appointments. Some mostly experience inner restlessness and racing thoughts. What matters is whether the difficulties have been there for a long time and affect everyday life.

Can you develop ADHD as an adult?

No. ADHD begins in childhood, but many only get the diagnosis as adults. This often happens when demands increase and the strategies you have previously managed with are no longer enough.

Is inner restlessness a symptom of ADHD?

Yes, it can be. In adults, hyperactivity often shows as inner restlessness, a need to be busy all the time or difficulty relaxing. However, inner restlessness can also be due to, e.g., anxiety or stress, so it must be seen in the context of everything else.

How do I know if it is ADHD or stress?

Stress typically arises in a particular period of high strain and eases when the strain is reduced. ADHD symptoms have been present since childhood and are also present in calm periods. However, many people with ADHD also experience stress, because everyday life requires extra energy.

Can you have ADHD without being hyperactive?

Yes. In predominantly inattentive ADHD, often called ADD, the difficulties are mainly with concentration, structure and getting started, while hyperactivity plays a smaller role or is not visible.

How long does an ADHD assessment take?

At Nordisk Psykiatri, an assessment can typically be completed within 4 weeks of the first consultation, and you do not need a referral. Read about waiting times for ADHD assessment in the public and private sectors.

Sources

• American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed., Text Revision (DSM-5-TR). American Psychiatric Association Publishing, 2022.
• National Institute for Health and Care Excellence (NICE). Attention deficit hyperactivity disorder: diagnosis and management (NG87).
• World Health Organization. International Classification of Diseases 11th Revision (ICD-11): Attention deficit hyperactivity disorder.
• Kooij, J.J.S. et al. Updated European Consensus Statement on diagnosis and treatment of adult ADHD. European Psychiatry, 2019.