bipolar I disorder
Summary
Bipolar I disorder is characterized by at least one manic episode lasting ≥1 week (or requiring hospitalization), often with depressive episodes. Manic episodes involve elevated mood, grandiosity, decreased need for sleep, and impaired judgment. It affects ~1% of the population with typical onset in late teens/early twenties.
Detail
Bipolar I disorder is a chronic mood disorder defined by the occurrence of at least one manic episode, which may be preceded or followed by hypomanic or major depressive episodes. Manic episodes are characterized by abnormally elevated, expansive, or irritable mood lasting at least one week (or any duration if hospitalization is required) plus ≥3 symptoms: grandiosity, decreased need for sleep (feeling rested after 2-3 hours), pressured speech, flight of ideas, distractibility, increased goal-directed activity or psychomotor agitation, and excessive involvement in risky activities. The pathophysiology involves dysregulation of neurotransmitter systems (dopamine, serotonin, norepinephrine) and structural brain abnormalities in prefrontal cortex and limbic regions. Strong genetic component with 60-85% heritability. Treatment includes mood stabilizers (lithium, valproate, carbamazepine), antipsychotics for acute mania, and psychotherapy. Untreated, it has high morbidity/mortality with increased suicide risk (15-20x general population). Differential diagnosis includes substance-induced mood disorder, medical conditions (hyperthyroidism), and other psychiatric disorders.
Sources
- DSM-5-TR
- Kaplan & Sadock's Synopsis of Psychiatry
- First Aid for the USMLE Step 1
- American Journal of Psychiatry
- Harrison's Principles of Internal Medicine
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