Bipolar disorder, also known as manic-depressive illness, is a brain disorder that causes unusual shifts in a person’s mood, energy, and ability to function. The mood episodes associated with the disorder persist from days to weeks or longer, and can be dramatic, with periods of being overly high and/or irritable to periods of persistent sadness and hopelessness.

Severe changes in behavior go along with the mood changes. These periods of highs and lows, called episodes of mania and depression, can be distinct episodes often recurring over time, or they may occur together in a so-called mixed state. Often people with bipolar disorder experience periods of normal mood in between mood episodes.

A manic episode is diagnosed if an elevated mood occurs with three or more primary symptoms most of the day, nearly every day, for at least one week. With an irritable mood, four additional symptoms must be present for a diagnosis.

Signs and symptoms of a manic episode can include the following:

  • Increased energy, activity, and restlessness
  • Excessively high, overly good, euphoric mood
  • Extreme irritability
  • Racing thoughts and talking very fast, jumping from one idea to another
  • Distractibility, inability to concentrate well
  • Little sleep needed
  • Unrealistic beliefs in one’s abilities and powers
  • Poor judgment
  • Spending sprees
  • A lasting period of behavior that is different from usual
  • Increased sexual drive
  • Abuse of drugs, particularly cocaine, alcohol, and sleeping medications
  • Provocative, intrusive, or aggressive behavior
  • Denial that anything is wrong


A depressive episode is diagnosed if five or more primary depressive symptoms last most of the day, nearly every day, for a period of two weeks or longer.

Signs and symptoms of a depressive episode can include the following:

  • Lasting sad 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, a feeling of fatigue or of being “slowed down”
  • Difficulty concentrating, remembering, making decisions
  • Restlessness or irritability
  • Sleeping too much, or having trouble sleeping
  • Change in appetite or unintended weight loss or gain
  • Thoughts of death or suicide, or suicide attempts

It can be helpful to think of bipolar disorder as a spectrum of moods. At one end is severe depression, above which is moderate depression, and then mild low mood, which may be called the blues when it is short-lived and dysthymia when it is chronic. Next is normal or balanced mood, then hypomania (mild mania that may feel good and be relatively brief and less severe), and then severe mania, which can include hallucinations, delusions, or other symptoms of psychosis.

Some people may experience symptoms of mania and depression together in what is called a mixed bipolar state. Symptoms often include agitation, trouble sleeping, significant change in appetite, psychosis, and suicidal thinking. A person may have a very sad hopeless mood even while feeling extremely energized.



Episodes of mania and depression typically recur across the life span. Between episodes, most people with bipolar disorder are free of symptoms, but as many as one-third find that some linger. A small percentage experience chronic unremitting symptoms despite treatment.

Bipolar I disorder is the classic form of the illness, which involves recurrent episodes of mania and depression. People with bipolar II disorder never develop severe mania; instead they experience episodes of hypomania that alternate with depression. When four or more episodes of illness occur within a twelve-month period, a person is said to have rapid-cycling bipolar disorder. Some people experience multiple episodes within a single week, or even within a single day. Rapid cycling tends to develop later in the course of illness and is more common among women than among men.

Most people with bipolar disorder can lead healthy and productive lives when the illness is properly treated. Without treatment, however, the disorder tends to worsen. Over time a person may suffer more frequent and more severe manic and depressive episodes than when the illness first appeared.

Some people with bipolar disorder become suicidal. Risk for suicide appears to be greater earlier in the course of the illness. A person with bipolar disorder, or anyone thinking about committing suicide, needs immediate attention from a mental health professional or a physician.