ADHD and Anxiety: Understanding the Overlap

ADHD and anxiety disorders frequently occur together in adults, and their overlapping symptoms can make them difficult to distinguish. Both can involve restlessness, problems with concentration, disrupted sleep and a mind that feels constantly busy, although the reasons behind these experiences may differ.

Research estimates suggest that around 25% to 50% of adults with ADHD also experience an anxiety disorder, with figures varying between studies. Understanding how the two conditions overlap, and where they differ, is important for an accurate diagnosis and a treatment plan that addresses each person’s needs.

What is ADHD?

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition that affects how a person manages attention, activity levels and impulses. It begins in childhood, although some people are not diagnosed until adulthood.

For adults, ADHD can make everyday responsibilities, such as organising tasks, keeping appointments or following conversations, more difficult. Symptoms vary, some people mainly experience attention difficulties, while others also have noticeable hyperactivity and impulsivity.

Common symptoms of ADHD in adults

• Difficulty maintaining attention: Becoming distracted during tasks or struggling to follow instructions.
• Forgetfulness: Missing appointments or frequently misplacing using items.
• Difficult tasks planning: Finding it hard to manage time and complete tasks.
• Restlessness: Fidgeting, needing to move or struggling to sit still.
• Impulsive behaviour: Interrupting conversations or making decisions without considering the consequences.

Occasionally experiencing these difficulties does not necessarily mean someone has ADHD. Assessment considers their history and impact across different areas of life. NHS guidance

What is anxiety?

Anxiety is a feeling of worry, unease or fear. Feeling anxious before an interview or during a stressful situation is common and does not automatically indicate a mental health condition.

An anxiety disorder involves anxiety that becomes difficult to manage and interferes with everyday life. There are different types. Generalised anxiety disorder (GAD), for example, involves persistent worry about several areas of life, rather than one specific situation.

Common symptoms of anxiety in adults

Symptoms vary depending on the person and the type of anxiety, but may include:

• Difficult-to-control worry: Repeatedly worrying about everyday concerns.
• Feeling on edge: Finding it hard to relax or feeling unusually restless.
• Concentration problems: Struggling to focus when worries occupy your attention.
• Sleep difficulties: Trouble falling asleep or staying asleep.
• Irritability and tiredness: Feeling easily frustrated or drained.
• Physical discomfort: Muscle tension, stomach problems, dizziness or a noticeable heartbeat.

Some of these symptoms overlap with ADHD, so a symptom list alone cannot reliably distinguish the two.

How ADHD causes anxiety

ADHD itself does not directly cause anxiety, but the lived experience of ADHD often does. Chronic difficulties with organisation, time management, and follow-through lead to repeated failures, missed deadlines, and relationship difficulties. Over time, this creates a pattern of anticipatory anxiety, a constant low-level fear of what will go wrong next.

Rejection sensitive dysphoria (RSD), which is common in ADHD, can also manifest as intense anxiety in social situations. The fear of saying the wrong thing, being judged, or disappointing others can lead to significant social anxiety that is actually rooted in ADHD rather than a primary anxiety disorder.

How anxiety affects ADHD

Anxiety can make ADHD symptoms harder to manage. Constant worry can make it more difficult to focus, plan tasks and get things done. Avoiding tasks that feel stressful can also lead to delays and unfinished work. This can create a cycle: ADHD-related difficulties increase worry, and that worry makes everyday tasks feel even harder.

Is overthinking a sign of ADHD?

Some people with ADHD experience overthinking, but it is not a core diagnostic symptom and does not, on its own, indicate ADHD. It might involve repeatedly reviewing a conversation, questioning a decision or struggling to move on from a concern.

Difficulties managing attention and emotions may contribute to these experiences. Worrying about forgotten tasks or missed deadlines can also leave someone feeling mentally preoccupied. However, overthinking can occur with anxiety or everyday stress too, so understanding the wider pattern matters more than this experience alone.

Which came first? The clinical importance of this question

In some cases, anxiety is a secondary consequence of untreated ADHD. In these cases, treating ADHD often reduces anxiety significantly, sometimes dramatically. In other cases, the anxiety disorder is primary and independent of ADHD. In these cases, treating the ADHD alone will not resolve the anxiety.

An ADHD assessment should review whether anxiety is linked to ADHD-related difficulties. This may include worries about meeting deadlines, managing work or handling social situations. For some people, these worries start or grow as adult responsibilities increase. Fears about forgetting things, being late or making mistakes can also offer clues, but they do not confirm the cause of anxiety on their own.

Distinguishing ADHD from anxiety

ADHD and anxiety can look similar on the surface. Both can cause difficulty concentrating, restlessness, and sleep problems. The key distinctions are:

Why ADHD and anxiety can be confused

ADHD and anxiety can be confused because both can involve restlessness, difficulty concentrating and trouble sleeping. An assessment needs to look beyond these shared symptoms to understand when they started, how they affect daily life and what might be causing them.

Clinicians consider patterns such as:

• ADHD: Attention difficulties, forgetfulness and impulsive behaviour that began in childhood and affect more than one area of life, such as work, home or relationships.
• Anxiety: Worry or fear that makes it difficult to concentrate, relax or manage everyday situations. Anxiety can begin in childhood or adulthood.

These signs can help explain the differences, but they cannot confirm a diagnosis. The NHS explains that people with ADHD may also have anxiety, so having an anxiety diagnosis does not mean you

An assessment looks at your childhood, current symptoms and mental health history. According to NICE guidance on ADHD diagnosis, questionnaires can help, but they cannot confirm ADHD on their own. The ADHD diagnosis helps identify whether your difficulties are linked to ADHD, anxiety, both or another condition.

Treatment considerations

When ADHD and anxiety co-occur, treatment typically involves addressing both conditions. The sequence matters, If the anxiety is secondary to ADHD, treating the ADHD first is often the most effective approach. As ADHD symptoms improve, the anxiety often reduces without specific treatment.

If anxiety is severe or occurs independently of ADHD, it may need treatment alongside or before ADHD treatment. An ADHD screening test can help identify signs that need further assessment, but it cannot confirm a diagnosis or decide which treatment is suitable. Stimulant medication can increase anxiety in some people, so a clinician may review the dose or consider a non-stimulant option such as atomoxetine, depending on the person’s symptoms and response.

Psychological support, particularly CBT, is effective for both conditions. CBT for ADHD addresses the thought patterns and behaviours that maintain ADHD-related difficulties, while CBT for anxiety addresses worry and avoidance.

The importance of a comprehensive assessment

Because ADHD and anxiety overlap so significantly, a comprehensive ADHD adult assessment is essential. An assessment that only screens for one condition risks missing the other, leading to incomplete or ineffective treatment. At ADHD Assessment UK, our assessments routinely explore co-occurring conditions including anxiety, depression, and autism.

Conclusion

ADHD and anxiety can cause similar difficulties, which can make them hard to tell apart. Some people have both conditions, while others feel anxious because of daily struggles linked to ADHD.

Looking at your symptoms and when they started can help explain what is happening. An ADHD assessment can explore these difficulties and help identify the support you need.

If worry, poor focus or restlessness is affecting your daily life, speak to your GP or a qualified clinician. With support suited to your needs, these difficulties can become easier to manage.