Bipolar disorder (formerly called manic-depressive illness or manic depression) is a mental disorder that causes unusual shifts in mood, energy, activity levels, concentration, and the ability to carry out day-to-day tasks. Bipolar disorder is typically diagnosed during late adolescence or early adulthood. Occasionally, bipolar symptoms can appear in children. Bipolar disorder can also first appear during a woman’s pregnancy or following childbirth. Although the symptoms may vary over time, bipolar disorder usually requires lifelong treatment. People with bipolar disorder experience periods of unusually intense emotion, changes in sleep patterns and activity levels, and uncharacteristic behaviors —often without recognizing their likely harmful or undesirable effects. These distinct periods are called «mood episodes». Mood episodes are very different from the moods and behaviors that are typical for the person. During an episode, the symptoms last every day for most of the day. Episodes may also last for longer periods, such as several days or weeks.