What is the diagnostic approach for a patient with suspected bipolar disorder, considering their symptoms, behavior, medical history, and potential genetic predisposition?

How to Diagnose Bipolar Disorder

Diagnosis of bipolar disorder requires strict adherence to DSM criteria, focusing on identifying distinct episodes of mood elevation (lasting at least 4 days for hypomania or 7 days for mania) characterized by decreased need for sleep, psychomotor activation, and marked departure from baseline functioning, while systematically ruling out medical causes and differentiating from conditions with overlapping presentations. 1

Core Diagnostic Approach

Essential Screening Questions

When evaluating any patient for bipolar disorder, particularly those presenting with depression, ask specifically about:

• Distinct periods of abnormally elevated, expansive, or euphoric mood that represent a clear change from baseline functioning 1
• Decreased need for sleep where the patient feels rested despite sleeping only 2-4 hours—this is a hallmark differentiating feature 1
• Psychomotor activation including markedly increased goal-directed activity or physical restlessness occurring spontaneously, not just in response to situations 1
• Racing thoughts, pressured speech, or flight of ideas during distinct time periods 1
• Grandiosity that represents a marked change in mental state rather than temperamental traits 1

Critical Historical Information Required

Your diagnostic assessment must include:

• Longitudinal symptom mapping using a life chart to document when specific symptom clusters began, their duration, and periods of remission 1
• Family psychiatric history, particularly of mood disorders and bipolar disorder, as there is a four- to sixfold increased risk in first-degree relatives 2
• Treatment response history, especially noting any antidepressant-induced mood elevation or agitation, as approximately 20% of youths with major depression eventually develop manic episodes 2
• Collateral information from family members, as patients often lack insight during manic episodes and family can describe behavioral changes more objectively 1

Applying DSM Duration Criteria

You must follow DSM duration criteria strictly: episodes must last at least 4 consecutive days for hypomania or 7 consecutive days for mania, with symptoms present most of the day, nearly every day. 1, 3 The mood disturbance must be sufficiently severe to cause marked impairment in social or occupational functioning or require hospitalization. 2

Medical Clearance Requirements

Before diagnosing bipolar disorder, complete a focused medical evaluation to exclude organic causes:

• Thyroid function tests, complete blood count, comprehensive metabolic panel to rule out metabolic and endocrine causes 2, 3
• Toxicology screening to assess temporal relationship between substance use and mood symptoms, as substance-induced mood disorder must be excluded 1
• Careful assessment of vital signs and neurologic examination, as numerous medical conditions (CNS infections, seizures, metabolic disturbances) can present with psychiatric symptoms 2

The goal is determining whether symptoms are caused or exacerbated by underlying medical conditions requiring acute treatment. 2

Critical Differential Diagnoses

Distinguishing from ADHD and Disruptive Behavior Disorders

Manic symptoms must be differentiated from ADHD, which is commonly comorbid but distinct. 1 Key differentiators:

• Episodic vs. chronic pattern: Bipolar presents with distinct episodes alternating with baseline or depressed mood, while ADHD symptoms are chronic and persistent 1
• Decreased need for sleep: Present in mania but not characteristic of ADHD 1
• Mood elevation: Euphoria or expansiveness occurs in mania but not ADHD 1

Distinguishing from Unipolar Depression

When a patient presents with depression, features suggesting bipolarity include:

• Depressive episodes with psychomotor retardation, hypersomnia, and psychotic features 1
• Mixed features with concurrent irritability, racing thoughts, or increased energy during depression 1
• Rapid onset depression with family history of bipolar disorder 2
• History of antidepressant-induced activation 2

Distinguishing from Borderline Personality Disorder

Both conditions share emotional dysregulation, but key differentiators include:

• Episodic vs. chronic pattern: Bipolar has distinct episodes with clear onset and offset; BPD has chronic, pervasive instability 1
• Decreased need for sleep: Hallmark of mania; in BPD, sleep problems relate to emotional distress rather than reduced sleep need 1
• Trigger patterns: BPD mood shifts are typically reactive to interpersonal stressors; manic mood changes occur spontaneously 1

Special Populations

Children and Adolescents

Bipolar disorder can be diagnosed in adolescents using the same DSM criteria as adults, with peak onset between ages 15-30. 1 However:

• In children under age 6, diagnostic validity has not been established—exercise extreme caution and consider alternative explanations first 1
• Juvenile mania is often characterized by symptom presentations that vary from classic adult descriptions, with markedly labile and erratic changes rather than persistent episodes 1
• Irritability, belligerence, and mixed features are more common than euphoria in pediatric presentations 1
• High rates of comorbid ADHD and disruptive behavior disorders complicate diagnosis, though ADHD history alone does not predict bipolar disorder in adulthood 2

High-Risk Patients

Pay particular attention to offspring of parents with bipolar disorder, who display more mood lability, anxiety, attention difficulties, hyperarousal, and depression than controls. 2 Premorbid anxiety and dysphoria are common, including in those whose first episode is depression. 2

Comprehensive Assessment Components

Your evaluation must document:

• Past and current psychiatric diagnoses, including prior diagnoses that may have been incorrect 1
• History of psychiatric hospitalizations and emergency visits for mood-related issues 1
• Detailed substance use history including tobacco, alcohol, marijuana, cocaine, hallucinogens, and misuse of prescribed medications 1
• Suicidality assessment including prior ideas, plans, attempts, and current impulsivity, as bipolar disorder has high rates of suicide attempts 1, 3
• Psychosocial stressors and environmental factors 2
• Comorbid conditions including anxiety disorders, substance use disorders, and developmental disorders 1

Monitoring and Reassessment

Initiate close monitoring before making a definitive diagnosis given the diagnostic complexity. 1, 4 Track mood patterns, sleep changes, and functional impairment prospectively. 1, 4 Schedule follow-up visits to observe symptom evolution over time, and reassess diagnosis periodically as the clinical picture may evolve. 1, 3

Common Diagnostic Pitfalls to Avoid

• Do not rely solely on irritability, as it is non-specific and occurs across multiple diagnoses 1
• Do not use screening questionnaires alone—all positive screens must trigger full diagnostic interviews using DSM criteria 1, 3
• Do not overlook the possibility of comorbid conditions when focusing on one diagnosis 1
• Do not diagnose based on checklists alone—assess symptoms in perspective given family, school, peer, and psychosocial factors 3
• Do not miss substance-induced presentations—obtain toxicology screening when substance use history is present 1