How do you distinguish between bipolar disorder and Attention Deficit Hyperactivity Disorder (ADHD)?

Distinguishing Bipolar Disorder from ADHD

The key to differentiating bipolar disorder from ADHD is identifying distinct episodic mood changes with true elation or grandiosity and decreased need for sleep (not just insomnia) in bipolar disorder, versus chronic, persistent symptoms without episodic fluctuation in ADHD. 1

Core Distinguishing Features

Mood Quality and Episodicity

• Bipolar disorder presents with episodic, distinct periods of elevated or expansive mood that represent marked changes from baseline functioning and are evident across all realms of life, not just reactions to situations. 1
• Look specifically for true elation or grandiosity as hallmark features—if neither is present, reconsider the bipolar diagnosis. 1
• ADHD presents with chronic, persistent symptoms that remain relatively stable over time without distinct episodic worsening or periods of normalcy between episodes. 1

Sleep Patterns: The Critical Differentiator

• Decreased need for sleep is a critical distinguishing feature—bipolar patients feel rested after minimal sleep during manic episodes, whereas ADHD patients may have difficulty initiating sleep but still require normal amounts of sleep to feel rested. 1
• Marked sleep disturbance is a hallmark sign of mania in bipolar disorder. 2

Temporal Course Analysis

• Organize clinical information longitudinally using a life chart to identify whether symptoms occur in distinct episodes (bipolar) or are chronic and persistent (ADHD). 1
• Bipolar disorder shows clear fluctuations in mood states with periods of relative normalcy or depression between episodes. 1
• Strictly apply DSM-5 duration criteria—manic episodes require at least 4-7 days of sustained symptoms. 1
• In adults, bipolar disorder is cyclical with episodes representing significant departure from baseline, while ADHD is associated with chronic trait-like symptoms and impairments. 2, 3

Critical Diagnostic Pitfalls to Avoid

The Irritability Trap

• Irritability alone cannot distinguish these disorders—it is common in both ADHD and bipolar disorder, as well as in disruptive behavior disorders. 1
• In bipolar disorder, irritability occurs as part of a distinct mood episode with other manic symptoms (racing thoughts, increased psychomotor activity, mood lability). 2, 1
• In ADHD, irritability is typically reactive to frustration or environmental triggers rather than part of an episodic mood syndrome. 1

Age-Specific Cautions

• Exercise extreme caution before diagnosing bipolar disorder in children younger than 6 years—the validity of this diagnosis in preschoolers has not been established. 1
• Many behaviors that appear manic (excessive silliness, giggling, boasting) are developmentally normal or related to disruptive behavior problems in preschool children. 1
• ADHD symptoms must have been present before age 12 years and persist for at least 6 months. 4

Practical Diagnostic Algorithm

Step 1: Screen for Distinct Mood Episodes

• Ask specifically about spontaneous periods when mood, energy, and behavior changed dramatically from baseline functioning. 1
• Inquire about rapid onset, psychomotor changes, and psychotic features during these periods. 2

Step 2: Identify Hallmark Manic Symptoms

• Look for elation or grandiosity—if neither is present, reconsider the bipolar diagnosis. 1
• Assess for racing thoughts, increased psychomotor activity, and marked mood lability during episodes. 2
• Evaluate for paranoia, confusion, or florid psychosis. 2

Step 3: Assess Sleep Patterns Carefully

• Decreased need for sleep (not just insomnia) strongly suggests mania. 1
• Determine if the patient feels rested after minimal sleep (bipolar) versus requiring normal sleep amounts despite difficulty falling asleep (ADHD). 1

Step 4: Map the Temporal Course

• Use a life chart to determine if symptoms are episodic with clear onset and offset (bipolar) or chronic and persistent (ADHD). 1
• Identify whether there are periods of normal functioning between symptomatic episodes. 2

Step 5: Evaluate Environmental Triggers

• ADHD symptoms worsen with loss of structure and are present across situations. 1, 4
• Bipolar episodes occur spontaneously without clear environmental precipitants. 1

Step 6: Gather Multi-Informant Data

• Verify symptoms and impairment in more than one setting using information from parents, teachers, and other observers. 4
• Parent report is more useful than teacher or youth report for discriminating bipolar cases in school-age children and adolescents. 1

Family History and Longitudinal Outcomes

• Increased family history of bipolar disorder supports a bipolar diagnosis, with a four- to sixfold increased risk in first-degree relatives. 2
• ADHD also shows strong familial patterns with high heritability, but without the same degree of mood disorder clustering. 2, 1
• Manic symptoms in boys with ADHD typically do not persist or evolve into DSM-5 bipolar disorder over 6-year follow-up. 1

Premorbid and Developmental Patterns

• Premorbid psychiatric problems are common in early-onset bipolar disorder, especially disruptive behavior disorders and behavioral dyscontrol. 2
• Most childhood bipolar cases are associated with ADHD, but follow-up studies of youths with ADHD have not shown increased rates of classic bipolar disorder as adults. 2
• Approximately 20% of youths with major depression go on to experience manic episodes by adulthood. 2

When Comorbidity is Present

• True comorbidity exists in approximately 20% of adult patients with ADHD who also have bipolar disorder, and 10-20% of patients with bipolar disorder have ADHD. 3
• Comorbid patients show both the episodic mood changes of bipolar disorder AND the persistent inattention/hyperactivity of ADHD. 1
• Comorbidity is associated with earlier age of onset, worse symptom burden, increased psychiatric morbidity, higher suicide attempt rates, and a more chronic and disabling course. 1, 3

Treatment Approach for Comorbidity

• Treat bipolar disorder first before addressing ADHD symptoms—mood stabilizers and atypical antipsychotics are primary treatments for bipolar disorder. 1
• Once mood is stabilized, stimulants may be used safely and effectively for ADHD symptoms. 1
• Data is mixed about whether stimulants or atomoxetine exacerbate mania in comorbid ADHD-BD, but consensus expert opinion recommends treating BD episodes first, potentially in stages (mood stabilizer first, then stimulant/atomoxetine). 5
• Particular care should be taken in using stimulants to treat ADHD in patients with comorbid bipolar disorder because of concern for possible induction of a mixed/manic episode. 6

Screening for Alternative Diagnoses

• Prior to initiating ADHD treatment with stimulants in patients with comorbid depressive symptoms, adequately screen to determine if they are at risk for bipolar disorder through detailed psychiatric history, including family history of suicide, bipolar disorder, and depression. 6
• Screen for common comorbid conditions that may alter treatment approach, including anxiety, depression, oppositional defiant disorder, conduct disorders, learning disabilities, and sleep disorders. 4