What is bipolar disorder?

What is Bipolar Disorder

Bipolar disorder is a chronic, recurrent mental illness characterized by distinct episodes of abnormally elevated mood (mania or hypomania) alternating with depressive episodes, affecting approximately 1-2% of the population and representing a leading cause of disability when left untreated. 1, 2

Core Clinical Features

The disorder is defined by the presence of manic, hypomanic, or mixed episodes, not simply by mood instability or irritability alone. 3

Manic Episodes

• A manic episode consists of a distinct period (lasting at least 7 days unless hospitalization is required) of abnormally and persistently elevated, expansive, or irritable mood with increased energy or activity 3, 4
• Key symptoms include decreased need for sleep without feeling tired, racing thoughts, pressured speech, grandiosity, and excessive involvement in pleasurable activities with high potential for painful consequences 3
• Elation and grandiosity are cardinal features that must be present—irritability alone does not constitute mania 5

Hypomanic Episodes

• Hypomania presents with similar symptoms to mania but is less severe, lasting at least 4 days 3
• These episodes do not cause marked impairment in social or occupational functioning and do not require hospitalization 3

Depressive Episodes

• Depressive episodes in bipolar disorder often present with psychomotor retardation and hypersomnia 3
• Irritability and anger may be prominent, especially in youth 3
• Patients spend the majority of their time experiencing depression, which typically is the presenting symptom 6

Diagnostic Subtypes

Bipolar I Disorder

• Requires at least one manic or mixed episode lasting at least 7 days (or requiring hospitalization) 3, 4
• Episodes of depression are not required for diagnosis, though most patients experience major or minor depressive episodes during their lifetime 3

Bipolar II Disorder

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

Mixed Episodes

• A mixed episode lasts 7 days or more with symptoms for both manic and depressive episodes met simultaneously 3
• This involves both elevated mood/increased energy and depressive symptoms occurring together 3

Rapid Cycling Pattern

• Rapid cycling is a course specifier (not a separate diagnosis) characterized by four or more distinct mood episodes occurring within a 12-month period 7
• Each episode must still meet full DSM duration criteria 7
• Ultra-rapid cycling involves brief episodes lasting hours to days with 5 to 364 cycles per year 5, 7

Epidemiology and Course

• Overall prevalence is approximately 1-2% in the general population 1, 2
• Peak age at onset ranges from 15 to 30 years 1
• The illness commonly starts in young adults and is a leading cause of disability and premature mortality 2
• Bipolar disorder is a lifelong condition requiring indefinite treatment 8

Critical Diagnostic Considerations

In Adults

• Rather than being a cyclical disorder with acute onset of clearly demarcated phases, bipolar disorder can present as chronic difficulties regulating moods, emotions, and behavior 1
• Early diagnosis is challenging and misdiagnoses are frequent, potentially resulting in missed early intervention and increasing risk of iatrogenic harm 2
• Physicians should maintain a high index of suspicion for bipolar disorder in any patient presenting with depression 6, 8

In Youth (Ages 13-17)

• Bipolar disorder in children and adolescents may present differently than in adults, with more irritability, mixed states, and rapid cycling 3
• Changes in mood, energy, and behavior are often more labile and erratic rather than persistent, with high rates of comorbidity, especially with ADHD and disruptive behavior disorders 3
• Diagnosis can be particularly challenging—symptom profiles can be variable, and pediatric patients may have variable patterns of periodicity of manic or mixed symptoms 4

Common Diagnostic Pitfalls

• Many explosive, dysregulated youth may not have true bipolar disorder—irritability and impulsivity alone do not constitute mania 5
• Elation and grandiosity must be present for diagnosis, not just irritability 5
• Brief outbursts lasting minutes are not manic episodes; true episodes require at least 4 hours (for ultra-rapid cycling) or days (for standard criteria) with full manic symptomatology 5
• Diagnostic confusion can occur between bipolar disorder and other conditions, particularly in adolescents with psychosis who may be misdiagnosed with schizophrenia 3
• A longitudinal history, rather than solely a cross-sectional assessment, is necessary for accurate diagnosis 3

Associated Morbidity and Mortality

• Affected individuals have higher rates of other mental health disorders, substance use disorders, and comorbid chronic medical illnesses 8
• Common comorbidities include other mental disorders, substance use disorders, migraine headaches, chronic pain, stroke, metabolic syndrome, and cardiovascular disease 6
• Patients with bipolar disorder are at high risk for suicide and their suicide attempts tend to be successful 6
• Quality of life is poorer in bipolar disorder than in other mood disorders and anxiety disorders 9
• Depressive symptoms account for much of the significant morbidity and mortality associated with bipolar disorder 9