What Is Bipolar Disorder?

Explore key differences between the types

Bipolar disorder is a mental health condition defined by periods (better known as episodes) of extreme mood disturbances. Bipolar affects a person's mood, thoughts, and behavior. 

There are two main types of bipolar disorders: bipolar I and bipolar II. According to the Diagnostic and Statistical Manual of Mental Disorders, bipolar I disorder involves episodes of severe mania and often depression. Bipolar II disorder involves a less severe form of mania called hypomania.

difference between bipolar i and bipolar ii
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Despite the major difference when it comes to mania in the two types of bipolar disorder, there are quite a few similarities in symptoms.

Depressive Episodes

In bipolar I disorder, a major depressive episode (one or more) usually occurs, but it is not required. Bipolar II disorder involves one or more major depressive episodes. Common symptoms that occur in a major depressive episode include:

  • Insomnia or hypersomnia
  • Unexplained or uncontrollable crying
  • Severe fatigue
  • Loss of interest in things the patient enjoys during euthymia
  • Recurring thoughts of death or suicide

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 1-800-273-8255 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911. 

For more mental health resources, see our National Helpline Database.

Both disorders may include periods of euthymia—symptom-free or "normal" states.


Manic episodes last at least seven days. An individual experiencing a manic episode may experience:

  • Feelings of euphoria
  • Less need for sleep
  • Increased sexual desire
  • Hallucinations or delusions
  • Marked increase in energy

During a manic episode, individuals may engage in risky or reckless behavior. For example, someone may indulge in risky sexual behavior, spend excessive amounts of money, or make impulsive decisions.

It's important to note that experiencing mania does not automatically mean a person will become violent or dangerous.

Sometimes people assume a "manic episode" means someone turns into a "maniac." That's not true.


An individual experiencing a hypomanic episode may experience similar symptoms but their functioning won't be markedly impaired. Many individuals who experience hypomania associated with bipolar II enjoy the increased energy and decreased need for sleep.

An episode of hypomania does not escalate to a point that a person needs hospitalization, which may happen with a person experiencing mania—especially if he or she is becoming a danger to others and/or themselves.


While the exact cause of bipolar disorder remains unclear, genetics is believed to play a major role. This is evidenced, in part, by studies of twins in which one or both had a bipolar I diagnosis. In 40% of identical twins (those with identical gene sets), both twins were found to be bipolar compared to less than 10% of fraternal twins (who don't share all the same genes).

Other contributing factors include abnormalities in a person’s brain circuitry, irregularities in neurotransmitters, and environmental factors such as childhood trauma or abuse.


When diagnosing bipolar disorder (regardless of the type), a mental health clinician must rule out other illnesses such as schizoaffective disorder, schizophrenia, delusional disorder, or schizophreniform disorder that may share similar symptoms.

Bipolar disorder cannot be diagnosed like other illnesses where a blood test, X-ray, or physical exam can provide a definitive diagnosis. The diagnosis is based on a set of criteria that a person must meet in order to be considered bipolar.

An informed diagnosis would likely include specific tests to exclude other physical contributions to the bipolar symptoms. This may involve a drug screen, imaging tests (CT scan or MRI of the brain), electroencephalogram (EEG), and a full battery of diagnostic blood tests. Your doctor will also ask you questions, and you should do your best to work closely with your healthcare team to confirm a diagnosis and find the right treatment plan for you.

Bipolar Disorder Discussion Guide

Get our printable guide to help you ask the right questions at your next doctor's appointment.

Mind Doc Guide


Treatment of bipolar I disorder is highly individualized and based on the types and severity of symptoms a person may be experiencing.

Mood stabilizers are the core of the treatment process, and other agents are often used, such as:

  • A mood stabilizer, such as lithium
  • Anticonvulsants to stabilize mood swings
  • Antipsychotics to control psychotic symptoms such as delusions ​and hallucinations, as well as the newer "atypical" antipsychotics which have mood-stabilizing properties of their own
  • Antidepressants (less commonly prescribed as they can trigger a manic episode)

In more severe cases, electroconvulsive therapy (ECT) may be used to help relieve mania or severe depression.

Both Types Should Be Properly Treated

Since hypomania is less severe than the mania that occurs in bipolar I disorder, bipolar II is often described as "milder" than bipolar I—but this is not completely accurate. Certainly, people with bipolar I can have more serious symptoms during mania, but hypomania is still a serious condition that can have life-changing consequences and so should be properly addressed.

In addition, research suggests that bipolar II disorder is dominated by longer and more severe episodes of depression. In fact, over time, people with bipolar II become less likely to return to fully normal functioning between episodes.

One study specifically concluded that bipolar type II was linked to a poorer health-related quality of life compared to type I. This remained true even during long periods of euthymia.

Thus, experts tend to believe that bipolar II disorder is equally (if not more) disabling than bipolar I disorder because it can lead to more lifetime days spent depressed and not doing as well overall between episodes. Proper treatment should be pursued for all types of bipolar disorders, and you should work closely with your healthcare team to figure out the best treatment for you.


As with many mental health conditions, bipolar disorder is associated with a certain stigma in society, which may make coping with the condition more difficult for you or a loved one. Know that stigma very often develops because of lack of knowledge—those who make comments or discriminate are usually ignorant or have fear based on what they think they know about the disorder.

Whether or not someone with bipolar faces stigma directly, know that the best way to cope with the condition is to connect with others who are experiencing it and get professional help. You can also fight stigma to help you cope better, and read up on your rights.

In Kids

Bipolar disorder can occur in kids of any age. It's important for parents and caregivers to be aware of the unique signs—they should pay attention to a child's functioning, feelings, and any family history of the disorder. With a timely diagnosis, a treatment plan for symptom management can be better established.

A Word From Verywell

Bipolar disorder is a complex mood disorder. If you are worried that you or a loved one has symptoms of a bipolar episode, seek medical attention for a proper evaluation.

Although bipolar is not curable, it is treatable. With the right medication and support, symptoms can be managed to the point where quality of life isn't drastically affected.

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8 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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