Explain bipolar disorder, including its symptoms, diagnosis, and treatment.

Understanding Bipolar Disorder

Bipolar disorder is a chronic psychiatric illness characterized by recurrent episodes of abnormally elevated mood (mania or hypomania) and depression, affecting approximately 1-2% of the global population and representing a leading cause of disability in young adults. 1, 2

Core Clinical Features

Manic Episodes

• A manic episode requires at least 7 consecutive days (or any duration if hospitalization is needed) of abnormally elevated, expansive, or irritable mood with increased energy, accompanied by at least three additional symptoms: decreased need for sleep without fatigue, racing thoughts, pressured speech, grandiosity, and excessive involvement in high-risk pleasurable activities. 3, 4
• The mood change represents a significant departure from baseline functioning that is evident and impairing across multiple life domains, not isolated to one setting or merely a reaction to situations. 4
• Manic episodes are marked by euphoria, grandiosity, reduced sleep need (a hallmark sign), mood lability with rapid extreme shifts, and may include psychotic features such as paranoia or florid psychosis. 4

Hypomanic Episodes

• Hypomania requires at least 4 consecutive days of similar symptoms to mania but less severe, without marked impairment in functioning or need for hospitalization. 3, 4
• The mood change must be spontaneous and not merely reactive to stressors or temperamental traits. 4

Depressive Episodes

• Depressive episodes feature psychomotor retardation, hypersomnia, significant suicidality, and often psychotic features. 4
• Bipolar depression is frequently misdiagnosed as unipolar depression, with up to 64% of depression encounters occurring in primary care where misdiagnosis is common. 5

Mixed Episodes

• A mixed episode requires 7 or more days where symptoms for both manic and depressive episodes are met simultaneously, involving both elevated mood/increased energy and depressive symptoms occurring together. 3, 4

Diagnostic Subtypes

Bipolar I Disorder

• Requires at least one manic or mixed episode lasting at least 7 days (unless hospitalization is required). 6, 3
• Episodes of depression are not required for diagnosis, though most patients experience major or minor depressive episodes during their lifetime. 6, 3

Bipolar II Disorder

• Requires periods of major depression and hypomania (episodes lasting at least 4 days), with no history of full manic or mixed episodes. 3

Bipolar Disorder Not Otherwise Specified (NOS)

• Diagnosed when bipolar features are present but do not meet full criteria for Bipolar I or II, such as when mood episodes last less than 4 days. 3, 4

Rapid Cycling

• Defined as four or more distinct mood episodes within 12 months, with each episode still meeting full duration criteria (7 days for mania, 4 days for hypomania). 4, 7
• Ultrarapid cycling involves 5-364 cycles per year, while ultradian cycling involves more than 365 cycles per year (daily mood shifts). 4, 7

Age-Specific Presentations

Adults

• Episodes represent a significant departure from baseline with a cyclical nature, distinct episode boundaries, and more classic presentation. 4

Adolescents

• Frequently associated with psychotic symptoms, markedly labile moods, mixed manic-depressive features, and more chronic, treatment-refractory course than adult-onset cases. 4
• Bipolar disorder with psychotic features is frequently misdiagnosed as schizophrenia in this age group. 3

Children

• Changes in mood, energy, and behavior are markedly labile and erratic rather than persistent, with irritability, belligerence, and mixed features more common than euphoria. 4
• High rates of comorbid ADHD and disruptive behavior disorders complicate diagnosis. 4
• The diagnostic validity of bipolar disorder in preschool children has not been established. 3

Critical Diagnostic Considerations

Key Distinguishing Features from Unipolar Depression

• Early-onset depression (before age 25), frequent depressive episodes, family history of serious mental illness, hypomania/mania symptoms within depressive episodes, and nonresponse to antidepressants all suggest bipolar rather than unipolar depression. 5
• Approximately 20% of youths with major depression develop manic episodes by adulthood. 4

Essential Assessment Components

• Use a longitudinal life chart approach to document exact duration of activated states, sleep changes, functional impairment across multiple settings, and cycling patterns over time—not just cross-sectional assessment. 3, 4
• Evaluate for decreased need for sleep during elevated mood states (not just insomnia), spontaneous mood changes (not reactive to stressors), and whether changes represent departure from baseline functioning. 3, 4
• Assess for psychotic features, which are common in adolescent presentations and help distinguish from other conditions. 3

Common Diagnostic Pitfalls

• Brief mood swings lasting minutes to hours do not meet DSM criteria, which require at least 4 days for hypomania and 7 days for mania. 3, 4
• Chronic baseline irritability without distinct episodes departing from baseline does not constitute hypomania. 3
• Mood changes reactive to stress or interpersonal conflict rather than spontaneous do not meet criteria. 3
• Irritability and emotional reactivity lack diagnostic specificity and are common across many psychiatric conditions including disruptive behavior disorders, ADHD, PTSD, and pervasive developmental disorders. 4

Differential Diagnosis Challenges

• Distinguish irritable mania from commonplace anger problems, especially given high comorbidity with disruptive behavior disorders. 4
• Disruptive behavior disorders exhibit chronic irritability as baseline rather than episodic departures. 4
• ADHD shows chronic overactivity without episodic nature or mood component. 4
• When the clinical picture remains ambiguous, particularly with psychotic symptoms present, refer to psychiatry for comprehensive assessment. 4

Comorbidities and Complications

• High rates of comorbid medical conditions including cardiovascular disease, hypertension, and obesity contribute to premature mortality. 5
• Psychiatric comorbidities are common, including ADHD, anxiety disorders, personality disorders, and substance use disorders. 5
• Adolescents with bipolar disorder have high rates of suicide attempts and substance abuse, requiring careful evaluation for suicidality. 3

Treatment Overview

Pharmacological Management

• Lithium remains the most effective drug overall for bipolar disorder, though full remission occurs only in a subset of patients. 1
• Cariprazine, fluoxetine/olanzapine, lurasidone, and quetiapine are FDA-approved for bipolar depression; only cariprazine and quetiapine are approved for both mania and depression. 5
• Unopposed monoamine antidepressants are often ineffective for bipolar depression and may cause treatment-emergent hypomania/mania, rapid cycling, or increased suicidality. 5
• Newer atypical antipsychotics show effectiveness in bipolar depression, though long-term tolerability and safety remain uncertain. 1

Psychosocial Interventions

• Evidence-based psychological treatments include interpersonal social rhythm therapy, family-focused treatment, and cognitive-behavioral therapy, which are vital for relapse prevention when combined with pharmacotherapy. 2, 8
• Combination therapy and adjunctive psychotherapy are often necessary to treat symptoms across different illness phases. 1

Prognosis and Long-Term Considerations

• Bipolar disorder is a chronic, often devastating illness that commonly starts in young adults and leads to significant disability. 1, 8
• Early diagnosis is challenging and misdiagnoses are frequent, potentially resulting in missed early intervention and increasing risk of iatrogenic harm. 1
• The illness shows marked variability between and within individuals across the lifespan. 1
• Despite over 15 approved treatments, outcomes are often suboptimal due to insufficient efficacy, side effects, or lack of availability. 1