How is bipolar disorder primarily defined?

Bipolar disorder is primarily defined by the cycling between periods of mania and depression. This condition is characterized by distinct phases where an individual experiences episodes of mania, which may include increased energy, elevated mood, or irritability, followed by episodes of depression, marked by low mood, loss of interest, and fatigue. Understanding this cycling nature is essential for recognizing the disorder's impact on mood regulation and functioning.

In contrast, the other choices do not capture the core aspects of bipolar disorder. Periods of hyperactivity and normalcy do not encompass the full range of bipolar experiences since the disorder specifically involves mood extremes rather than simply alternating states of normalcy and hyperactivity. A consistent state of depression would be more indicative of unipolar depression rather than bipolar disorder, which inherently includes manic episodes. Similarly, an obsession with self-image pertains to conditions like body dysmorphic disorder or narcissistic personality traits and does not reflect the mood variability central to bipolar disorder.