ADHD vs Anxiety: How Psychologists Distinguish Between Overlapping Symptoms

When someone describes difficulty concentrating, feeling restless, or struggling to complete everyday tasks, the underlying cause is not always immediately clear. These experiences are common to both attention-deficit/hyperactivity disorder (ADHD) and anxiety disorders, and distinguishing between them requires careful clinical consideration and judgement, rather than a simple checklist. At our clinic, we frequently meet individuals and families who have received conflicting feedback from teachers, physicians, or other professionals about whether the core issue is ADHD, anxiety, or perhaps both. This confusion is understandable because the surface symptoms can look remarkably similar, even to trained observers. In this article, we explain the clinical reasoning process psychologists use during a psychodiagnostic assessment to differentiate these conditions, why accurate diagnosis matters for treatment outcomes, and what you should expect from a thorough evaluation.

Why ADHD and Anxiety Are So Often Confused

The overlap between ADHD and anxiety is not a coincidence. Both conditions affect cognitive functions (e.g. concentration, attention), emotional regulation, mood, the ability to manage daily demands, and much more. A child who cannot focus during class may be struggling with ADHD-related attentional difficulties, or they may be consumed by worry about an upcoming test. An adult who procrastinates on important tasks might have difficulty initiating work due to executive function challenges, or they might be avoiding tasks because of fear of failure or judgment.

The specific symptoms that appear in both conditions include:

• Difficulty concentrating and staying on task
• Restlessness and an inability to sit still
• Task avoidance and procrastination
• Sleep difficulties, including trouble falling or staying asleep
• Irritability and emotional reactivity
• Forgetfulness in daily activities

Research confirms this overlap is substantial. According to the research on ADHD and anxiety symptom overlap, approximately 25 to 50 percent of individuals with ADHD also meet criteria for an anxiety disorder. This high comorbidity rate means that having one condition significantly increases the likelihood of having the other, further complicating the diagnostic picture.

Parents often tell us they have received different assessments from different settings. A teacher might describe a child as “anxious and worried,” while a sports coach sees impulsivity and boundless energy. These observations are not necessarily contradictory. They reflect how symptoms manifest differently across contexts and why professional assessment is essential for understanding the full picture.

The Clinical Reasoning Process: How Psychologists Distinguish Between ADHD and Anxiety

When we conduct a psychological diagnostic assessment, we are not simply matching symptoms to a checklist. We are investigating the underlying mechanisms driving the presenting concerns and exploring the contexts in which they are surfacing. The DSM-5 diagnostic criteria for ADHD provide a framework, but skilled clinical reasoning is required to determine whether those criteria are truly met or whether another condition better explains the symptoms.

What Is the Primary Driver of Concentration Difficulty?

This question sits at the heart of differential diagnosis. In ADHD, attention regulation is the core deficit. The brain has difficulty filtering distractions, sustaining focus on non-preferred tasks, and shifting attention appropriately. A person with ADHD may struggle to concentrate even during calm, low-stress situations and even on tasks they want to complete.

In anxiety, worry and rumination consume cognitive resources. The person can concentrate when they are not anxious, but their mental bandwidth is hijacked by catastrophic thoughts, fear of negative outcomes, or physical sensations of tension. If we remove the source of anxiety, concentration typically improves.

Consider this example: A child who cannot focus during a math test might have ADHD if they also struggle to pay attention during their favourite video game or during relaxed family time. However, if that same child concentrates well during preferred activities but “blanks out” only during evaluations or social situations, anxiety may be the primary driver.

When Did Symptoms First Appear?

ADHD is a neurodevelopmental condition, meaning it reflects atypical brain development beginning in childhood. According to DSM-5 criteria, several ADHD symptoms must have been present before age 12. We ask detailed questions about early childhood behaviour, school performance in primary grades, and feedback from early teachers and caregivers.

Anxiety disorders may have later onset, often triggered by life events, developmental transitions, or accumulating stress. An adult who reports that they “managed fine” through their twenties but developed concentration problems only after a major life change is more likely presenting with anxiety or trauma-related difficulties than with lifelong ADHD.

This developmental history is crucial. We spend considerable time gathering information about school reports, early childhood experiences, and patterns across the lifespan rather than focusing only on current symptoms.

Are Symptoms Consistent Across Settings or Situation-Specific?

ADHD symptoms typically appear across multiple contexts: home, school, work, and social situations. The person with ADHD struggles with attention regulation regardless of the setting, though the specific impact may vary. Anxiety symptoms, in contrast, may intensify in specific situations that trigger worry or fear and improve in contexts that feel safe.

We gather information from multiple sources and settings. For children, this means obtaining input from parents, teachers, and other caregivers. For adults, we may include feedback from partners, colleagues, or family members who observe the person across different contexts.

What Is the Quality of the Restlessness?

Both ADHD and anxiety can produce restlessness, but the subjective experience differs. ADHD-related hyperactivity involves motor-driven restlessness: a need for movement, difficulty staying seated, feeling “driven by a motor,” and seeking high-stimulation environments. This restlessness is often present even in calm, pleasant situations.

Anxiety-related restlessness involves tension and worry-based agitation. The person feels “keyed up” or “on edge,” often accompanied by physical sensations like tight muscles, rapid heartbeat, or shortness of breath. This restlessness is tied to perceived threat or anticipatory worry rather than an intrinsic need for stimulation.

Assessment Components That Enable Accurate Differential Diagnosis

A comprehensive ADHD assessment includes multiple components specifically designed to distinguish ADHD from other conditions with overlapping symptoms. Understanding how psychological testing works can help you appreciate why thorough evaluation matters.

Developmental and Family History

We conduct an extensive interview covering childhood development, academic history, family mental health patterns, and the timeline of symptom emergence. This information helps establish whether symptoms align with the neurodevelopmental trajectory of ADHD or suggest another origin.

Standardized Rating Scales

We use validated instruments that measure ADHD symptoms and anxiety symptoms separately. This allows us to quantify symptom severity in each domain and compare patterns. Importantly, these scales provide normative data so we can determine whether reported symptoms exceed typical levels for the person’s age and gender.

Clinical Interview Exploring Symptom Context

Beyond rating scales, we engage in detailed conversation about specific situations where symptoms occur, what makes them better or worse, and how they impact daily functioning. This qualitative information is essential for understanding the mechanisms behind the symptoms.

Cognitive Testing

When indicated, we include measures of attention, working memory, processing speed, and executive function. These tests can reveal attention regulation patterns consistent with ADHD versus performance fluctuations driven mainly by anxiety. A person with primary ADHD often shows deficits even on untimed, low-stakes tasks, whereas a person with primary anxiety may perform well until stress or evaluation pressure is introduced.

In some cases, qEEG brain mapping can provide additional information about brain activity patterns, though this is used as supplemental data within a comprehensive evaluation rather than as a standalone diagnostic tool.

The Comorbidity Reality: When Both ADHD and Anxiety Are Present

One of the most important insights from clinical research is that ADHD and anxiety frequently co-occur. An estimated 8.4 percent of children and 2.5 percent of adults have ADHD, with boys more commonly diagnosed than girls. Among those with ADHD, roughly a quarter to half also meet criteria for at least one anxiety disorder.

This comorbidity creates a clinical reality that assessment protocols must address:

• Untreated ADHD can lead to secondary anxiety. Years of struggling with attention, experiencing criticism for “not trying hard enough,” and falling short of one’s potential can create anxious expectations and avoidance behaviours.
• Chronic anxiety can create attention difficulties that mimic ADHD. When the mind is constantly occupied with worry, cognitive resources for attention and task completion are depleted.
• Having both conditions simultaneously is common. The conditions interact, with ADHD-related failures fueling anxiety and anxiety further disrupting concentration.

A thorough psychological diagnostic assessment evaluates for both conditions rather than stopping at the first identified diagnosis. When both ADHD and anxiety are present, treatment planning becomes more complex, and the sequencing of interventions may depend on which condition is causing the most impairment.

Treatment Implications: Why Accurate Diagnosis Matters

The stakes of differential diagnosis are high because ADHD and anxiety respond to different intervention approaches. Misdiagnosis can lead to ineffective treatment or, in some cases, interventions that worsen symptoms.

For example:

• Stimulant medications that effectively address ADHD symptoms may exacerbate anxiety if anxiety is the primary condition
• Anxiety-focused interventions alone will not address core ADHD symptoms of attention dysregulation
• Behavioural strategies designed for ADHD may not help if the underlying issue is fear and avoidance

Accurate diagnosis enables targeted treatment planning. Rather than a trial-and-error approach that leaves families frustrated and individuals discouraged, a clear understanding of the underlying condition guides appropriate referrals and intervention selection. For more information about ADHD specifically, see our page on understanding ADHD.

Questions to Ask Your Assessor About Differential Diagnosis

If you or your child are seeking evaluation for possible ADHD or anxiety, asking informed questions can help you evaluate assessment quality. Consider asking:

1. “What assessment tools will you use to distinguish between ADHD and anxiety?” A thorough assessment should include measures for both conditions.
2. “How will you determine if symptoms are due to one condition, both, or something else?” The assessor should be able to explain their clinical reasoning process.
3. “Will the assessment include developmental history and symptom onset evaluation?” Timeline matters for differential diagnosis.
4. “How do you assess for comorbidity?” Given how frequently these conditions co-occur, this should be part of standard practice.
5. “What happens if the results are unclear or complex?” Complex presentations may require additional testing or consultation.

These questions help ensure that your assessment will be comprehensive enough to provide meaningful diagnostic clarity rather than a quick screening that misses nuances.

Who This Article Is For—and Who It Is Not For

This article is written for:

• Adults who suspect they may have ADHD, anxiety, or both and want to understand what professional assessment involves
• Parents who have received conflicting feedback about their child’s behaviour and are seeking clarity
• Individuals who have struggled with focus issues but are not sure of the underlying cause
• Anyone preparing for a psychological assessment who wants to understand the diagnostic process

This article is not intended as a self-diagnosis tool. The information here is educational and cannot replace a comprehensive evaluation by a qualified professional. If you recognize yourself in these descriptions, the appropriate next step is to seek a professional assessment rather than to conclude you have a specific diagnosis.

Moving Toward Clarity

Distinguishing ADHD from anxiety is one of the most challenging diagnostic tasks in clinical psychology. The overlap in symptoms is real and substantial, and even experienced professionals must use careful clinical reasoning to arrive at accurate conclusions. What matters is not whether you can “pass” a symptom checklist, but whether a skilled clinician can understand the mechanisms driving your difficulties and the developmental context in which they emerged.

The good news is that comprehensive psychological diagnostic assessment can provide this clarity. By gathering information from multiple sources, using validated measurement tools, exploring symptom context and history, and applying clinical expertise, psychologists can distinguish between conditions that appear similar on the surface but have very different implications for treatment.

At our clinic, ADHD Assessment protocols are designed to provide this level of diagnostic clarity, addressing the complexity of overlapping symptoms and comorbidity with the thoroughness these questions deserve. If you have been wondering whether ADHD, anxiety, or both might be affecting your life or your child’s life, we encourage you to reach out for a consultation. Understanding the underlying condition is the foundation for effective support.

Laura Stradwick

Dr. Laura S. Stradwick is the director of Stradwick Psychology & Neurofeedback Clinic, where she specializes in evidence-based psychological services integrating client collaboration. She is a licensed clinical psychologist and board certified in Neurofeedback by the BCIA, with membership in various professional associations. Dr. Stradwick holds a Doctoral degree in Clinical Psychology from the Illinois School of Professional Psychology and a Bachelor’s degree from the University of Western Ontario. Her therapeutic approach is client-centered and integrative, emphasizing trust and a compassionate environment to foster psychological resilience and personal growth.