Bipolar I Disorder
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- Bipolar I (BP-I) is an episodic mood disorder of at least one manic or mixed (mania and depression) episode that causes marked impairment, psychosis, and/or hospitalization; major depressive episodes are not required but usually occur.
- Symptoms are not caused by a substance or general medical condition.
New onset in older patients (>50 years of age) requires a workup for organic or chemically induced pathology.
Diagnosis less well defined. For example, mood elevation symptoms overlap with those of ADHD.
- Pregnancy does not reduce risk of mood episodes.
- Need to weigh risk of exposure to mood episode to that of medication
- Avoid divalproex due to high teratogenicity risk.
- Postpartum carries risk of severe acute episode with psychosis and/or infanticidal ideation.
Onset usually between 15 and 30 years of age
- 1.0–1.6% lifetime prevalence
- Equal among men and women (manic episodes more common in men; depressive episodes more common in women)
- Equal among races; however, clinicians tend to diagnose schizoaffective in African Americans with BP-I.
Etiology and Pathophysiology
Genetic predisposition and major life stressors can trigger initial and subsequent episodes:
- Dysregulation of biogenic amines or neurotransmitters (particularly serotonin, norepinephrine, and dopamine)
- MRI findings suggest abnormalities in prefrontal cortical areas, striatum, and amygdala that predate illness onset (1)[C].
- Monozygotic twin concordance 40–70%
- Dizygotic twin concordance 5–25%
- 50% have at least one parent with a mood disorder.
- First-degree relatives are 7 times more likely to develop BP-I than the general population.
Genetics, major life stressors, or substance abuse
No known way to prevent onset, but treatment adherence and education can help to prevent relapses.
Commonly Associated Conditions
Substance abuse (60%), ADHD, anxiety disorders, and eating disorders