The defining feature of bipolar disorder is mania. It can be the triggering episode of the disorder, followed by a depressive episode, or it can first manifest after years of depressive episodes. The switch between mania and depression can be abrupt, and moods can oscillate rapidly. Mania that is mild to moderate, called hypomania, can be deceptive: It is often experienced as a surge in energy that can feel good and enhance productivity and creativity. As a result, a person may deny that anything is wrong. There is great variability in manic symptoms, but features may include:
The duration of elevated moods and the frequency with which they alternate with depressive moods can vary enormously from person to person as well. Frequent fluctuation, known as rapid cycling, is not uncommon, and is defined as at least four episodes per year. While an episode of mania is what distinguishes bipolar disorder from unipolar depression, the depression of bipolar disorder can be the predominating feature so that a person spends far more time in the depressed state than in a manic or hypomanic one. While there is great variability in degree and duration of depressive symptoms, features generally include:
• Lasting sad, anxious, or empty mood
• feelings of hopelessness or pessimism
• feelings of guilt, worthlessness, or helplessness
• loss of interest or pleasure in activities once enjoyed, including sex
• decreased energy, feelings of fatigue or of being "slowed down"
• difficulty concentrating, remembering, or making decisions
• restlessness or irritability
• sleeping too much or inability to sleep or stay asleep
• change in appetite and/or unintended weight loss or gain
•chronic pain or other persistent physical symptoms not accounted for by illness or injury
• thoughts of death or suicide, or suicide attempts.
Not infrequently, the symptoms of mania and depression can occur together in "mixed" episodes. Symptoms of a mixed state can include agitation, trouble sleeping, significant change in appetite, psychosis, and suicidal thinking. A person can feel sad in mood yet highly energized.