What is the approach to clinically diagnosing Attention Deficit Hyperactivity Disorder (ADHD)?

Clinical Diagnosis of ADHD

The clinical diagnosis of ADHD requires a comprehensive evaluation using DSM-5 criteria, with symptoms present for at least 6 months in multiple settings, causing significant impairment, and including standardized rating scales from multiple informants. 1

Diagnostic Criteria and Assessment Process

Core Symptoms Assessment

• Inattentive symptoms (≥6 for children under 17, ≥5 for adults):

  • Poor attention to detail, careless mistakes
  • Difficulty sustaining attention
  • Appears not to listen when spoken to
  • Fails to follow through on tasks
  • Organizational difficulties
  • Avoids tasks requiring sustained mental effort
  • Loses necessary items
  • Easily distracted
  • Forgetful in daily activities 1

• Hyperactive-impulsive symptoms (≥6 for children under 17, ≥5 for adults):

  • Fidgeting/squirming
  • Difficulty remaining seated
  • Inappropriate running/climbing (inner restlessness in adults)
  • Difficulty engaging in quiet activities
  • Often "on the go"
  • Excessive talking
  • Blurts out answers
  • Difficulty waiting turn
  • Interrupts or intrudes on others 1

Presentation Types

1. Predominantly inattentive
2. Predominantly hyperactive-impulsive
3. Combined type 1

Essential Diagnostic Requirements

• Symptoms present before age 12
• Symptoms present in ≥2 settings (e.g., home, school, work)
• Clear evidence of functional impairment
• Symptoms not better explained by another disorder 1

Multi-Informant Assessment

A proper ADHD diagnosis requires gathering information from multiple sources:

• Standardized rating scales from at least two teachers or other sources
• Parent/caregiver observations
• Self-report from the patient
• Direct clinical observation 1

The American Academy of Pediatrics emphasizes that behavior rating scales remain the standard of care in assessing diagnostic criteria for ADHD, though they should not be used in isolation 2.

Differential Diagnosis and Comorbidities

Key Differential Features

ADHD must be distinguished from other conditions with overlapping symptoms:

Feature	ADHD	Bipolar Disorder
Symptom onset	Before age 12	Typically after age 12
Course	Chronic, persistent	Episodic, cyclical
Mood symptoms	Not primary feature	Central to diagnosis
Psychotic symptoms	Absent	May be present

Common Comorbidities to Screen For

• Learning disabilities
• Sleep disorders
• Depression
• Anxiety
• Conduct disorder
• Oppositional defiant disorder 2, 1

Comorbidities are extremely common (present in up to 80% of cases) and can complicate diagnosis 3.

Age-Specific Considerations

Children

• More likely to display obvious hyperactive behaviors
• Difficulty sitting still in classroom settings
• Problems with peer relationships and following rules
• Academic difficulties are common 1

Adults

• Hyperactivity often internalized as restlessness
• Inattention may be masked by anxiety or compensatory strategies
• Difficulties with time management, organization, task completion
• Struggles with maintaining employment or relationships 1, 3

Diagnostic Pitfalls to Avoid

1. Relying solely on symptom checklists - While useful, these should not be the only basis for diagnosis 4

2. Inconsistent assessment between professionals - Research shows low inter-professional reliability between different specialists (kappa=0.39), suggesting the need for standardized approaches 4

3. Overlooking cultural factors - Cultural differences can affect perception and reporting of symptoms 2

4. Missing comorbidities - Failing to identify co-occurring conditions can lead to incomplete treatment 1, 3

5. Inadequate functional assessment - ADHD diagnosis requires evidence of impairment in social, academic, or occupational functioning 1, 5

Recommended Diagnostic Algorithm

1. Initial screening: Use validated ADHD screening tools with both patient and observers

2. Comprehensive clinical interview:

   • Detailed developmental history
   • Age of symptom onset (before 12)
   • Symptom persistence and chronicity
   • Functional impairment assessment across domains
   • Family history (ADHD has strong heritability)

3. Multi-informant assessment:

   • Collect standardized rating scales from multiple sources
   • Include at least 2 teachers/observers
   • Parent observations
   • Self-report when age-appropriate

4. Rule out alternative explanations:

   • Medical conditions
   • Other psychiatric disorders
   • Environmental factors
   • Substance use

5. Screen for comorbidities:

   • Learning disabilities
   • Mood disorders
   • Anxiety disorders
   • Sleep disorders
   • Substance use disorders

6. Synthesize findings to determine if DSM-5 criteria are met, including:

   • Sufficient symptoms (≥6 for children, ≥5 for adults)
   • Duration ≥6 months
   • Onset before age 12
   • Presence in multiple settings
   • Significant functional impairment
   • Not better explained by another condition 2, 1

The diagnosis of ADHD is clinical and should be made by clinicians with appropriate training and expertise in evaluating the complex symptom presentation and potential comorbidities associated with this neurodevelopmental disorder 1, 3.