ADHD vs Anxiety: Understanding Why Misdiagnosis Happens

Written by Dr. Simon Khela MBChB MRCGP, GMC Registered Doctor

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I see this mix-up often enough that it's become one of the more predictable conversations in clinic. A patient comes in convinced they have anxiety, they can't concentrate, they feel constantly on edge, they're forgetting things, and by the end of the assessment it turns out what's actually driving it is undiagnosed ADHD. Just as often, it runs the other way: someone's been managing what they assumed was ADHD for years, and it turns out to be anxiety that's never been properly treated.

Neither of those outcomes is a small thing. Get the diagnosis wrong, and you get the treatment wrong too — medication that doesn't touch the actual problem, therapy aimed at the wrong target, months or years of feeling like nothing's working because nothing was ever addressing the right condition.

What is ADHD?

ADHD (attention deficit hyperactivity disorder) is a neurodevelopmental condition. That means it's rooted in how the brain is wired for attention, impulse control and activity regulation, and it's present from childhood even if it isn't picked up until much later.

It usually shows up in one of three patterns:

• Inattentive type — difficulty sustaining focus, losing track of tasks, forgetfulness, being easily sidetracked
• Hyperactive-impulsive type — restlessness, interrupting, acting before thinking things through
• Combined type — a mix of both

Adults don't always look like the stereotype. Hyperactivity in adulthood is often internal rather than visible — a constant sense of needing to be doing something, difficulty sitting still through a long meeting, or a mind that feels like it's always running two or three tasks behind where it should be.

What is anxiety?

Anxiety is, at its core, a normal response to threat that's become disproportionate or persistent. It stops being useful and starts interfering with daily life. A few forms come up regularly:

• Generalised anxiety disorder (GAD) — ongoing, hard-to-control worry about everyday things
• Social anxiety — fear of judgement or embarrassment in social situations
• Panic disorder — sudden, intense episodes of fear, often with physical symptoms
• Phobias — a strong, specific fear of a particular object or situation

Unlike ADHD, anxiety can develop at any age, often in response to a specific stressor, and it tends to come with physical symptoms alongside the mental ones — a racing heart, muscle tension, sweating, trouble sleeping.

Why the symptoms overlap

ADHD and anxiety can both produce restlessness, poor concentration and irritability, which is exactly why they get confused so often. Someone with ADHD might look anxious because they're struggling to keep on top of tasks and deadlines. Someone with anxiety might look inattentive because their mind is too busy running through worst-case scenarios to focus on what's in front of them.

They also genuinely coexist a lot of the time. Research consistently finds that a substantial proportion of adults with ADHD — commonly cited at somewhere between a third and half — also meet the criteria for an anxiety disorder. That overlap makes the diagnostic picture genuinely harder to untangle, not just superficially similar.

Key differences

Once you know what to look for, a few patterns tend to separate the two.

Focus and attention. With ADHD, attention is inconsistent regardless of how much you want to concentrate — you can be genuinely interested in something and still lose your grip on it. With anxiety, the ability to focus is usually intact until worry takes over; the problem isn't attention itself, it's what's competing for it.

Source of distractibility. ADHD distraction tends to be unpredictable — your mind jumps to something entirely unrelated mid-task. Anxiety-driven distraction is usually thematic: the same worry, or a version of it, keeps pulling your attention back regardless of what you're trying to do.

Physical symptoms. Anxiety often comes with a physical signature — a racing heart, sweating, nausea, muscle tension. ADHD can involve fidgeting and restlessness, but not the same autonomic surge.

Motivation and procrastination. In ADHD, procrastination is usually about difficulty starting a task in the first place — executive function struggling to get going, even on things you want to do. In anxiety, procrastination is more often about avoidance — putting something off because of what it might mean if it goes wrong.

Why misdiagnosis happens

Beyond the symptom overlap itself, a few other things make misdiagnosis common.

There's still a lingering assumption that ADHD looks like a hyperactive young boy, and that anxiety is just "overthinking." Neither is accurate, and both assumptions steer people away from the right diagnosis.

This shows up most clearly in women and girls, where ADHD is frequently missed altogether. The inattentive presentation — daydreaming, quiet disorganisation, emotional sensitivity — doesn't match the disruptive stereotype most people picture, so it gets labelled as anxiety or low mood instead, sometimes for years. We've written more on this in our guide to ADHD in women and girls, because it's a pattern we see often enough to warrant its own explanation. There's also a real overlap worth knowing about between ADHD and autism presentations — we cover that separately in ADHD vs autism and AuDHD, for anyone whose picture doesn't fit neatly into either box.

And because the two conditions co-occur so often, it's entirely possible to have both and only ever get treated for one of them.

How diagnosis works

A proper assessment for either condition should involve more than a quick conversation. In our clinic, and in line with NICE's guidance on ADHD diagnosis, it typically includes:

• A detailed history of when symptoms started and how they've developed over time
• Standardised questionnaires or rating scales specific to ADHD or anxiety
• A structured clinical interview, sometimes drawing on input from a partner or family member where that's useful
• Ruling out other conditions that could explain the same symptoms

If the picture is complicated, referral to a specialist — a psychiatrist or ADHD specialist for further assessment — may be appropriate. We've written a fuller breakdown of what that process looks like in the UK in how ADHD is diagnosed, and on the specific ways misdiagnosis tends to happen in our guide to ADHD misdiagnosis.

Treatment options

Treatment looks different depending on which condition — or combination — is actually driving the symptoms.

For ADHD, options usually include:

• Medication, such as stimulant or non-stimulant treatments prescribed and monitored by a specialist
• Behavioural strategies and coaching to build routines around organisation and time management
• Practical adjustments at work or home to reduce friction around common difficulties

For anxiety, options usually include:

• Cognitive behavioural therapy (CBT), which helps identify and work through the thought patterns driving the anxiety
• Mindfulness and relaxation techniques
• Medication, such as SSRIs, where appropriate
• Lifestyle changes — sleep, exercise, and reducing caffeine and alcohol, all of which can meaningfully worsen anxiety symptoms

Treating one condition when the other is actually present rarely goes well. Anxiety medication given to someone whose real issue is ADHD may take the edge off but won't touch the underlying attention and organisational difficulties — which is exactly why getting the diagnosis right matters more than getting to a diagnosis quickly.

When to seek help

It's worth arranging an assessment if:

• Symptoms are affecting your work, relationships or day-to-day functioning
• You've tried managing things yourself without much improvement
• You suspect you might have both conditions rather than just one
• You're not sure which label actually fits what you're experiencing

You don't need to have a firm answer before booking an assessment. Working out which condition — or combination — is behind your symptoms is exactly what the assessment is for.

Book an assessment

If you're unsure whether ADHD, anxiety, or both are behind what you're experiencing, a proper assessment is the fastest way to find out — and the only reliable route to the right treatment. At Private Medical Clinic, our assessments cover both conditions, starting with an online GP consultation and moving through to a personalised treatment plan, with same-day and virtual appointments available.

Book an ADHD and anxiety assessment with one of our GMC-registered doctors.

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Frequently asked questions About ADHD and Anxiety