What are the steps and tools for diagnosing Attention Deficit Hyperactivity Disorder (ADHD) in adults?

Diagnosing ADHD in Adults Over Age 18

The diagnosis of ADHD in adults requires a comprehensive psychiatric evaluation with particular focus on documenting core ADHD symptoms that began in childhood, obtaining collateral information from family members or significant others, ruling out alternative diagnoses, and utilizing structured rating scales to systematically assess symptoms and functional impairment across multiple life domains. 1

Step 1: Conduct a Complete Psychiatric Evaluation

Establish childhood onset of symptoms:

• Document that ADHD symptoms were present before age 12 years (DSM-5 criteria require onset before this age) 1
• Symptoms must have persisted for at least 6 months 1
• Obtain detailed developmental history focusing on inattention, hyperactivity, and impulsivity during childhood 1
• Use the Wender Parent's Rating Scale or Wender Utah Rating Scales to retrospectively assess childhood ADHD symptoms 1

Assess current adult symptoms:

• Evaluate for 5 or more symptoms of inattention (e.g., difficulty sustaining attention, easily distracted, forgetful, difficulty organizing tasks) 1
• Evaluate for 5 or more symptoms of hyperactivity-impulsivity (e.g., restlessness, excessive talking, interrupting others, impatience) 1
• Determine ADHD subtype: predominantly inattentive, predominantly hyperactive-impulsive, or combined presentation 1

Step 2: Obtain Collateral Information

Adults with ADHD often have poor insight and underestimate the severity of their symptoms and resulting impairments, making collateral information essential: 1

• Interview spouse, significant other, parent, or close friend about the patient's symptoms 1
• Have collateral sources complete rating scales with the patient in mind 1
• Gather information about functional impairment across multiple settings 1

Step 3: Utilize Structured Rating Scales

Implement validated assessment tools to systematically document symptoms:

• Adult ADHD Self-Report Scale (ASRS): Use Part A for initial screening; if positive, complete Part B for comprehensive symptom assessment 1, 2
• Conners Adult ADHD Rating Scale (CAARS): Validated tool for evaluating ADHD symptoms in adults 1, 2
• Brown Attention-Deficit Disorder Scale for Adults: Assesses executive function deficits associated with ADHD 1
• Weiss Functional Impairment Rating Scale-Self (WFIRS-S): Measures ADHD-specific functional impairment in domains such as home management, work, relationships, and time management 1

Step 4: Document Functional Impairment in Multiple Settings

Verify that symptoms cause clinically significant impairment in more than one major setting: 1, 3

• Social functioning (relationships, social interactions) 3
• Occupational functioning (job performance, job instability, employment status) 1
• Academic functioning (if applicable) 3
• Home management (organizing household tasks, managing appointments) 1

Step 5: Complete Medical History and Physical Examination

Rule out medical conditions that might mimic ADHD:

• Obtain comprehensive medical history 1
• Perform physical examination 1
• Order screening laboratory tests to exclude medical conditions presenting with similar symptoms 1

Step 6: Screen for Comorbid Conditions

ADHD has high rates of psychiatric comorbidity that must be systematically assessed: 1

Substance use disorders:

• Obtain detailed history of drug and alcohol use 1
• Consider urine drug screen given high comorbidity rates 1
• Assess for current substance abuse or dependence 4

Mood and anxiety disorders:

• Screen for depression, bipolar disorder, and anxiety disorders 1, 2
• These conditions have overlapping symptoms with ADHD and frequently co-occur 4, 2

Other psychiatric conditions:

• Evaluate for personality disorders (particularly borderline and antisocial patterns) 1, 4
• Assess for oppositional defiant disorder and conduct disorder 1
• Screen for impulse control disorders 2

Developmental and cognitive conditions:

• Evaluate for learning disabilities 1
• Assess for undiagnosed borderline intellectual functioning 1

Sleep disorders:

• Screen for sleep apnea and other sleep disturbances that can mimic ADHD symptoms 1

Step 7: Rule Out Alternative Diagnoses

Establish differential diagnosis to exclude conditions with similar presentations: 1

• Bipolar disorder (mood instability, impulsivity) 1
• Major depressive disorder (concentration difficulties, psychomotor changes) 1
• Anxiety disorders (restlessness, difficulty concentrating) 1
• Personality disorders (impulsivity, relationship instability) 1, 4
• Narcolepsy (excessive daytime sleepiness, attention problems) 1
• Substance-induced symptoms 1

Step 8: Consider Symptom and Response Validity Testing

When diagnostic uncertainty exists or symptom exaggeration is suspected:

• Implement symptom validity tests to detect invalid symptom presentation 5
• These tests have good sensitivity and very good specificity in detecting feigned symptoms 5
• Particularly important in contexts where secondary gain is possible (disability evaluations, academic accommodations) 5

Common Pitfalls to Avoid

Relying solely on self-report without collateral information: Adults with ADHD characteristically underestimate their symptoms and impairments 1

Failing to establish childhood onset: ADHD is a neurodevelopmental disorder that must have originated in childhood; adult-onset symptoms suggest alternative diagnoses 1

Misdiagnosing comorbid conditions as ADHD: Conditions like atypical depression, cyclothymia, and borderline personality disorder are commonly misdiagnosed as ADHD 4

Using rating scales alone without comprehensive clinical evaluation: Rating scales systematically collect information but do not diagnose ADHD by themselves 3

Overlooking substance use: The high rate of comorbid substance abuse necessitates thorough screening 1

Inadequate assessment of functional impairment: Documentation of impairment across multiple life domains is required for diagnosis 1, 3