Which condition is a mood disorder characterized by alternating periods of depression and mania?

• A. Depression
• B. Dementia
• C. Bipolar disorder
• D. Cancer

Answer: (C)

Bipolar disorder is a mood disorder in which a person experiences episodes of depression followed by episodes of mania (or hypomania). During depressive phases, mood and energy are low, interests fade, and activity may drop. During manic phases, mood is elevated, energy is high, sleep needs drop, speech may be rapid, thoughts can race, and risky or impulsive behaviors may occur. The defining feature is these distinct periods of alternating low and high mood, not just a single mood state. Depression alone describes only the low mood part, dementia involves cognitive decline, and cancer is a medical disease unrelated to mood disorders.