ADHD or anxiety? How to tell the difference

Why ADHD and anxiety overlap so much

Both ADHD and anxiety disorders activate the brain's threat-response system. Anxiety does so in response to perceived danger or worry; ADHD does so through dysregulation of dopamine and norepinephrine systems that govern attention, executive function, and emotional regulation. The downstream symptoms — difficulty concentrating, racing or intrusive thoughts, restlessness, difficulty sleeping, irritability, and a persistent sense of dread about uncompleted tasks — are functionally identical to a GP taking a brief history.

The confusion is compounded by the fact that ADHD itself generates anxiety. When you repeatedly forget important things, miss deadlines, lose belongings, say the wrong thing in social situations, and fail to perform to the level your intelligence suggests you should, the result is chronic low-level stress that meets clinical criteria for generalised anxiety disorder. In this sense, ADHD can cause secondary anxiety — which means treating only the anxiety, without addressing the underlying ADHD, rarely resolves the problem fully.

Key differences between ADHD and anxiety

While overlap is significant, there are distinguishing features that a thorough assessment will probe:

• Context-dependence of concentration. In ADHD, concentration difficulties are highly context-dependent. A person with ADHD can hyperfocus intensely on a topic that interests them — sometimes for hours — while being completely unable to focus on something boring or anxiety-provoking. Anxiety-driven concentration difficulties tend to be more uniform: worry intrudes regardless of interest level.
• Childhood onset. DSM-5 requires ADHD symptoms to have been present before age 12. Anxiety disorders can develop at any point in life, often linked to identifiable life events or stressors. If you have childhood evidence of inattention, impulsivity or hyperactivity, ADHD becomes significantly more likely.
• Executive function impairment. ADHD has a specific signature of executive function difficulty: working memory failures, poor time estimation ("time blindness"), difficulty initiating tasks even when you want to do them, disorganisation and losing things. These are not anxiety symptoms, though anxiety can make them worse.
• Response to worry content. People with anxiety can often identify what they are worried about, and the worry has a logical (if exaggerated) relationship to real concerns. People with ADHD often describe a free-floating restlessness or inability to settle that is not attached to specific worries.
• Response to treatment. SSRIs and talking therapies (particularly CBT) are first-line treatments for anxiety and work well when anxiety is the primary diagnosis. If you have tried these with limited benefit despite adequate dose and duration, ADHD as a primary or contributing diagnosis should be considered.

When both ADHD and anxiety are present

Approximately 50% of adults diagnosed with ADHD also meet criteria for at least one anxiety disorder, according to studies published in journals including the Journal of Attention Disorders and cited in NICE evidence reviews. This is not coincidence. The mechanisms interact in several directions:

• ADHD-driven chaos and social difficulties generate secondary anxiety (as described above).
• Anxiety-driven avoidance and overthinking exacerbate ADHD executive-function difficulties, creating a feedback loop.
• Some ADHD medications (particularly stimulants at higher doses) can worsen anxiety, so treatment sequencing and dose titration require care when both conditions are present.
• Masking behaviours — using anxiety-driven hyper-vigilance to compensate for ADHD disorganisation — are very common in women and can make both conditions appear less severe than they are in formal assessment settings.

The clinical implication is that when both are present, treating only one typically provides incomplete relief. A good assessment will identify both, and a good treatment plan will address both.

Why GPs systematically misdiagnose anxiety first

Several systemic factors drive the pattern of ADHD being missed and anxiety being diagnosed first:

• Time constraints. A 10-minute GP appointment is sufficient to recognise distress and prescribe an SSRI; it is wholly inadequate for ADHD screening, which requires a detailed developmental and symptom history going back to childhood.
• Training gaps. ADHD receives relatively little coverage in UK medical school curricula. Many GPs graduated before adult ADHD was widely recognised as a clinical entity.
• Presentation bias. The stereotype of ADHD (a hyperactive boy who cannot sit still) is not how most adults with ADHD present. Adults have often developed compensatory strategies. Inattentive presentation, which is more common in women, presents as dreamy and distracted rather than disruptive.
• Anxiety is easier to treat in primary care. GPs can prescribe SSRIs independently and refer for CBT via IAPT without needing a specialist. ADHD assessment requires secondary care referral, which takes longer and costs the ICB money.
• The treating-the-symptom trap. When someone presents with anxiety, the anxiety is treated. If the underlying ADHD is not identified, the anxiety is partly driven by unmanaged ADHD chaos — so it keeps returning, leading to repeated treatments, augmentation strategies, and growing frustration.

Asking for reassessment under NICE NG87

If you have received an anxiety diagnosis and believe ADHD may be a better explanation for your symptoms (or an additional one), you are entitled to ask your GP for an ADHD assessment referral under NICE guideline NG87. You do not need to have failed all anxiety treatments first, though having tried one or two SSRIs without sustained benefit strengthens your case.

A useful framing for your GP appointment: "I have been treated for anxiety for [X years] and while [medication/therapy] helps somewhat, I still have significant difficulties with [concentration, working memory, time management, completing tasks]. I would like to be referred for an ADHD assessment under NICE NG87, which recommends that ADHD is considered when these symptoms are present. I would like to use Right to Choose to be referred to [provider name]."

Your GP cannot refuse a referral solely on the grounds that you have an existing anxiety diagnosis. NICE NG87 is explicit that differential diagnosis should consider ADHD even in the presence of anxiety.

If your GP is resistant, asking for it to be noted in your medical record that you have requested an ADHD assessment and been refused is often effective — GPs are more cautious when their decisions are documented.

What a proper ADHD assessment looks like

NICE NG87 sets out what an adult ADHD assessment should cover. Whether you access it via NHS Right to Choose or private self-pay, the assessment should include:

• A structured clinical interview of at least 60–90 minutes covering childhood symptoms, current symptoms across multiple settings (home, work, relationships), and functional impairment.
• Validated rating scales: the Adult ADHD Self-Report Scale (ASRS-v1.1) is a widely used screening tool; many services also use the Conners Adult ADHD Rating Scales or the Brown ADD Rating Scales.
• Collateral information: a questionnaire completed by someone who knew you in childhood and/or a current close contact. This is particularly important for distinguishing ADHD (present since childhood) from anxiety disorders that developed in adulthood.
• Differential diagnosis: the assessor should explicitly consider and document whether symptoms are better explained by anxiety, depression, autism, bipolar disorder, sleep disorder, or substance use — and should note where conditions co-occur.
• A written report clearly stating which DSM-5 or ICD-11 criteria are or are not met, with clinical reasoning.

A valid assessment cannot be conducted in under 45 minutes or without any collateral information. If a provider is offering "assessments" significantly shorter than this, or without requesting collateral, the quality of the resulting diagnosis is questionable.

Frequently asked questions