What is Bipolar 1 Disorder
Bipolar I disorder is a severe psychiatric condition defined by the occurrence of at least one manic episode lasting 7 days or more (or requiring hospitalization), characterized by abnormally elevated, expansive, or irritable mood with increased energy, decreased need for sleep, racing thoughts, pressured speech, grandiosity, and excessive involvement in high-risk activities. 1, 2
Core Diagnostic Requirements
The diagnosis of Bipolar I disorder requires only one manic episode—depressive episodes are not necessary for diagnosis, though most patients will experience them during their lifetime. 1 This distinguishes it from Bipolar II disorder, which requires both hypomanic episodes (lasting at least 4 days) and major depressive episodes, but never a full manic episode. 1, 3
Defining Features of a Manic Episode
A manic episode represents a distinct period of abnormally and persistently elevated, expansive, or irritable mood with the following characteristics: 1
- Decreased need for sleep without feeling tired (not just insomnia—patients can stay awake for days with little fatigue) 1, 4
- Racing thoughts and pressured speech (rapid, difficult-to-interrupt talking) 1
- Grandiosity (inflated self-esteem or unrealistic beliefs about one's abilities) 1
- Increased goal-directed activity or psychomotor agitation 1
- Excessive involvement in pleasurable activities with high potential for painful consequences (e.g., spending sprees, sexual indiscretions, foolish business investments) 1, 2
The episode must represent a significant departure from the individual's baseline functioning and last at least 7 days, unless hospitalization is required (in which case duration criteria are met regardless of length). 1, 2
Mixed Episodes and Rapid Cycling
A mixed episode involves simultaneous manic and depressive symptoms occurring together for at least 7 days, such as elevated mood with racing thoughts alongside depressed mood and suicidal ideation. 1, 4 This presentation is particularly dangerous and requires immediate clinical attention. 4
Rapid cycling is a course specifier (not a separate diagnosis) characterized by four or more distinct mood episodes within 12 months, with each episode still meeting full duration criteria. 5 In children and adolescents, even more rapid patterns may occur (ultrarapid or ultradian cycling), though these terms are not part of formal DSM criteria. 6, 5
Clinical Course and Epidemiology
Bipolar I disorder affects approximately 0.4-1.6% of the general population, with equal distribution between sexes, though early-onset cases (before age 13) are predominantly male. 6 The disorder is chronic and severe, associated with substantial psychosocial impairment and a loss of 10-20 potential years of life, primarily due to cardiovascular disease and suicide. 3
Although mania defines the disorder, depressive episodes and symptoms dominate the longitudinal course and disproportionately account for morbidity and mortality. 3 Patients spend far more time depressed than manic over their lifetime. 3
Special Considerations in Youth
In children and adolescents, bipolar disorder often presents differently than in adults, with more irritability, mixed states, rapid cycling, and chronic rather than episodic patterns. 6, 1 The mood changes may be more labile and erratic rather than persistent distinct episodes. 1 This has led to diagnostic controversy, as many youth presenting with outbursts, mood lability, irritability, and aggression are now receiving bipolar diagnoses. 6
Diagnostic confusion historically occurred between bipolar disorder and schizophrenia in adolescents, as mania during adolescence often presents with psychosis. 6 Better adherence to DSM criteria has reduced this misdiagnosis. 6
Pathophysiology and Heritability
Bipolar disorder has high heritability (approximately 70%) and shares genetic risk alleles with other psychiatric and medical disorders. 3 Implicated pathogenic processes include disturbances in neuronal-glial plasticity, monoaminergic signaling, inflammatory homeostasis, cellular metabolic pathways, and mitochondrial function. 3 The high prevalence of childhood maltreatment in people with bipolar disorder suggests environmental exposures significantly influence disease presentation and severity. 3
Common Pitfalls
Do not confuse decreased need for sleep (a manic symptom where patients feel energized despite minimal sleep) with insomnia or hypersomnia (depressive symptoms where patients struggle with sleep but feel tired). 1, 4 If a depressed bipolar patient suddenly stops sleeping and appears energized, this signals a switch to mania or mixed state requiring immediate intervention. 4
A longitudinal history is essential—cross-sectional assessment alone is insufficient for accurate diagnosis. 1 Consider changes in energy, activity, and sleep patterns in addition to mood symptoms. 1