Which of the following best describes a manic episode?

A manic episode is characterized by a period of elevated mood that lasts for at least one week and is accompanied by additional symptoms that lead to significant impairment in social or occupational functioning. During this time, individuals may experience increased energy, decreased need for sleep, racing thoughts, grandiosity, impulsivity, and distractibility.

The key aspect that makes this answer correct is the duration of the elevated mood and the presence of associated symptoms that characterize the episode. This duration of one week or more distinguishes it from other mood disturbances, such as hypomanic episodes, which are also elevated but have a shorter duration (at least 4 days) and lack the full-blown characteristics of mania. Additionally, the significant impact on daily functioning during a manic episode is crucial for diagnosis.

As for the other options, a distinct period of depressed mood pertains to depression, not mania. A phase of stable mood and energy does not reflect the fluctuations and extremes present in a manic episode. Lastly, a brief change in mood lasting less than three days would not meet the criteria for a manic episode, as the symptoms must persist over a longer timeframe to qualify.