How to differentiate between Attention Deficit Hyperactivity Disorder (ADHD) and anxiety in a pediatric or young adult patient during history taking?

Differentiating ADHD from Anxiety During History Taking

Focus your history on three critical distinguishing features: age of symptom onset (ADHD begins before age 12), pattern of symptoms across settings (ADHD is pervasive while anxiety is often situational), and the presence or absence of trauma-specific reexperiencing and avoidance symptoms (present in anxiety/trauma disorders but absent in ADHD). 1, 2

Core Temporal and Developmental Distinctions

Age of Onset:

• ADHD symptoms must have begun before age 12 and persisted across multiple settings since childhood. 1, 2 This is a mandatory DSM-5 criterion that cannot be waived.
• Anxiety disorders can develop at any age and often emerge acutely following specific stressors or trauma exposure. 2
• Ask specifically: "When did you first notice these attention problems—was it in early elementary school or did it start more recently?" 1

Pattern Across Settings:

• ADHD requires documented impairment in more than one major setting (home, school, social). 1, 2 The symptoms are pervasive and chronic.
• Anxiety-related attention problems are often situational and tied to specific triggers or contexts. 2, 3
• Obtain collateral information from parents, teachers, and other school personnel to verify cross-setting impairment. 1, 2

Symptom-Specific Differentiating Features

Hyperarousal vs. Hyperactivity:

• Anxiety disorders share hyperarousal features with ADHD (restlessness, difficulty relaxing, feeling "driven by a motor"), but these symptoms in anxiety lack the developmental continuity from early childhood. 2, 4
• Some hyperactivity symptoms like "difficulty relaxing" and "feeling driven by a motor" load more strongly onto anxiety factors than ADHD factors in adults with clinical anxiety. 4 Be cautious interpreting these symptoms in isolation.
• True ADHD hyperactivity manifests as excessive motor activity that has been present since early childhood across all settings. 1

Attention Problems—Primary vs. Secondary:

• In ADHD, inattention is a primary neurodevelopmental deficit present from early childhood. 1, 2
• In anxiety, attention problems are secondary to worry, rumination, or hypervigilance and often fluctuate with anxiety severity. 3, 5
• Ask: "Do you have trouble paying attention because your mind wanders to random things, or because you're worrying about specific concerns?" 5

Trauma-Specific Symptoms:

• Anxiety disorders, particularly PTSD, include trauma-specific reexperiencing (flashbacks, nightmares) and avoidance symptoms that ADHD completely lacks. 2
• Conduct a detailed trauma history including onset, duration, and relationship to current symptoms. 2
• The presence of dissociation, alterations in consciousness, or trauma-triggered symptom exacerbations points toward anxiety/trauma disorders rather than ADHD. 2

Critical History-Taking Questions

Developmental Timeline:

• "Were you having these problems in kindergarten and first grade, or did they start later?" 1, 2
• "Did teachers comment on attention or behavior problems in early elementary school report cards?" 1

Functional Impairment Pattern:

• "Do these problems happen everywhere—at home, at school, with friends—or mainly in certain situations?" 1, 2
• "What makes the symptoms better or worse?" (Anxiety symptoms often have identifiable triggers; ADHD symptoms are more constant.) 2, 5

Response to Demands:

• "Does the child use oppositional behavior to avoid overwhelming demands?" (This may indicate anxiety rather than primary ADHD.) 3
• In anxiety, avoidance is often a coping mechanism for managing overwhelming feelings. 3

Mandatory Comorbidity Screening

Screen simultaneously for both conditions, as they co-occur in approximately 14% of children with ADHD, with rates increasing with age. 3, 6 The presence of comorbidity significantly worsens functional outcomes and alters treatment approach. 2, 3

Essential screening domains:

• Depression (present in ~9% of ADHD cases) 3
• Substance use disorders, particularly in adolescents 1, 2
• Learning disabilities and language disorders 1, 2
• Sleep disorders (can both mimic and exacerbate ADHD symptoms) 1
• Trauma exposure and PTSD symptoms 2

Common Diagnostic Pitfalls

Symptom Overlap Trap:

• Restlessness, difficulty concentrating, and sleep problems occur in both disorders. 6, 4 Do not diagnose based on these symptoms alone.
• Look beyond overlapping symptoms to the developmental course and trauma-specific features. 4

Retrospective Reporting Bias:

• Tools like the Wender Utah Rating Scale contain many "internalizing" items that inflate retrospective ADHD diagnoses in anxious adults. 7
• Always verify childhood symptoms through collateral sources (old report cards, parent interviews) rather than relying solely on patient recall. 1, 7

Bidirectional Relationship:

• ADHD symptoms can exacerbate anxiety, and anxiety can worsen attention and executive functioning. 3, 6 Both may be present.
• When both are present, approximately 45% of adults with retrospective ADHD continue to meet criteria for current ADHD. 7

Treatment Response as Diagnostic Information

If diagnostic uncertainty persists after comprehensive history:

• Treating ADHD with stimulants often improves ADHD-related anxiety symptoms. 5, 8 If anxiety worsens with stimulants, reconsider the primary diagnosis.
• Treating anxiety can reduce anxiety-related attentional problems and executive dysfunction. 5
• When ADHD and anxiety are comorbid, treat the anxiety disorder until clear symptom reduction is observed before expecting full ADHD symptom control. 2, 3