Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Bipolar Disorder

(Manic-Depressive Disorder)


The Manual's Editorial Staff

Reviewed/Revised Nov 2021 | Modified Sep 2022
Get the full details

What is bipolar disorder?

Bipolar disorder is a mental disorder that has periods of depression and periods of mania.

Depression is feeling so sad you can’t do daily activities or don’t want to do things you used to enjoy.

Mania is a state in which you have abnormally high energy and confidence, are easily distracted, and make risky decisions.

  • Bipolar disorder usually starts when you're in your teens, 20s, or 30s

  • Bipolar disorder probably runs in families

  • Your mood will be mostly normal when you're not having a period of depression or mania

  • Doctors treat bipolar disorder with medicines and psychotherapy

There are 2 types of bipolar disorder, bipolar 1 and bipolar 2.

If you have bipolar 1 disorder, you have:

  • At least 1 period of mania that prevents you from doing daily activities and that may include delusions (when you can’t tell what is real)

  • Usually, periods of depression

If you have bipolar 2 disorder, you have:

  • At least 1 period of less severe mania (hypomania)

  • Periods of severe depression

What causes bipolar disorder?

Doctors don’t know exactly what causes bipolar disorder. Your genes (genetic information you get from your parents and grandparents) may play a role.

Periods of mania (manic episodes) can be triggered by:

  • Higher or lower levels of certain chemicals (neurotransmitters) in a person’s body—neurotransmitters are chemicals such as serotonin and norepinephrine that nerve cells use to send messages in the brain and body

  • Brain tumors or other brain disorders

  • A stressful event

  • Drugs, such as cocaine

  • Other health problems, such as thyroid problems

What are the symptoms of bipolar disorder?

Periods (episodes) of depression or mania come and go. In between, your mood may be normal. Episodes of depression and mania can last a few weeks or up to 6 months.

Depression symptoms:

  • Feeling very sad

  • Less interest in activities, even ones you used to enjoy

  • Thinking and moving slowly

  • Feeling hopeless and guilty

  • Sleeping more than usual

  • Seeing things that aren’t real

Mania symptoms:

  • Feeling very confident and thinking you're your best self

  • Having lots of energy

  • Getting irritated easily

  • Sleeping less than usual

  • Talking more

  • Getting distracted easily and changing from one activity to another

  • Taking part in risky activities, such as gambling or sex, without thinking about the effects

  • Sometimes seeing and hearing things that aren’t real

People with severe mania (manic psychosis) may have symptoms like:

  • False belief that they are special, such as that they are Jesus or a genius

  • Thinking people are after them, such as being watched by the FBI

  • Extreme activity, such as racing about, screaming, and singing

  • Not thinking or acting reasonably

People with severe mania need to go to the hospital right away.

How can doctors tell if I have bipolar disorder?

Doctors will suspect bipolar disorder based on the pattern of your symptoms. When you have mania, you may not be able to accurately report your symptoms because you don't think anything is wrong with you. So doctors may ask for information from family members.

Doctors may also do blood or urine tests to check if other medicines or health problems could be causing your symptoms.

How do doctors treat bipolar disorder?

Doctors may:

  • Prescribe medicine, such as lithium or valproate

  • Provide group or individual counseling (psychotherapy)

  • If medicine doesn't help your depression, give electroconvulsive therapy (once called shock therapy)

In electroconvulsive therapy, your doctor will put you to sleep with medicines and then send an electric current through your brain. Doctors don't know why, but the electric current often helps depression go away.

If you have severe mania or depression or are taking risks that could result in serious problems, doctors may treat you in the hospital.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Eskalith, Eskalith CR, Lithobid
quiz link

Test your knowledge

Take a Quiz!