What's the Difference Between Bipolar I and Bipolar II Disorder?

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What Is Bipolar Disorder?

Bipolar disorder is marked by periods of extreme mood swings, including manic or hypomanic episodes, and often involves periods of depression. Although having a parent or sibling with bipolar disorder does not guarantee that someone will develop these symptoms, there is a strong genetic component to this diagnosis.

Bipolar disorder is a treatable condition, and some therapies and medications can reduce symptoms and improve quality of life. However, being diagnosed with bipolar disorder can be scary and confusing. Understanding the different types can help in determining the best treatment path for you.

This article covers the differences between bipolar I and bipolar II disorder and discusses the treatment options available for each.

Bipolar I vs. Bipolar II Disorder

Let's take a look at some of the major differences between bipolar I and bipolar II disorder. While each can be debilitating, they each have unique symptoms. More details about these symptoms are explained further in this article.

Bipolar I Disorder
  • Includes a history of at least one full manic episode

  • Is often associated with a depressive episode

  • May include psychotic features in the context of mood episodes

Bipolar II Disorder
  • Includes a history of at least one hypomanic episode and no history of full manic episodes

  • Is often associated with a depressive episode

  • Psychosis is absent

What Is Bipolar I Disorder?

According to the "Diagnostic and Statistical Manual of Mental Disorders, 5th Edition" (DSM-5), in order for someone to be diagnosed with bipolar I disorder, they must have a history of at least one manic episode.

A manic episode consists of a period of at least one week and involves three or more of the following:

  • Inflated self-esteem or grandiosity
  • Reduced need for sleep
  • More talkative than usual or pressured speech
  • Racing thoughts or flight of ideas
  • Increased distractibility
  • Agitated movement or increased goal-directed activity
  • Engaging in risky activities, including physically dangerous choices, impulsive buying sprees, or unsafe sexual behavior

The episode must cause impairment and might require hospitalization due to unsafe behavior. People experiencing a manic episode due to bipolar I disorder might have hallucinations or delusions.

What Is Bipolar II Disorder?

Bipolar II disorder is often associated with a major depressive episode as well as at least one hypomanic episode. According to the DSM-5, a hypomanic episode consists of three or more symptoms of a manic episode lasting four days or longer.


A hypomanic episode is less severe than a manic episode in that its duration is shorter. Hypomanic episodes do not include delusions or hallucinations.

Bipolar II disorder is less severe than bipolar I disorder, as a hypomanic episode is less intense and causes less impairment than a manic episode. However, either diagnosis causes difficulty with functioning. Both conditions are treatable and have options for evidence-based interventions.

Depressive Symptoms and Bipolar Disorder

Although most individuals with a bipolar disorder diagnosis experience depressive symptoms, a history of major depressive episodes are not necessary to diagnose bipolar I disorder if an individual has experienced a full manic episode.

A diagnosis of bipolar II disorder requires a history of at least one depressive episode.

A major depressive episode consists of five or more symptoms lasting two weeks or longer, including either depressed mood or loss of interest:

  • Daily or nearly daily depressed mood lasting most of the day
  • Lowered or absent interest in activities
  • Significant weight loss or decreased appetite
  • Either difficulty sleeping or increased need for sleep
  • Physical restlessness
  • Fatigue or low energy occurring nearly every day
  • Feelings of worthlessness or guilt
  • Difficulty concentrating or indecisiveness
  • Thoughts of death or suicidal ideation

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.

Treatment

Both bipolar I and bipolar II disorder are mood disorders that are marked by extreme highs and lows. You and your treatment team will work together to create a treatment plan that fits your unique needs.

Although there are some differences in recommendations for bipolar I and bipolar II disorder, recommendations are similar for the two diagnoses. Treatment options include:

  • Medication: The manic symptoms of both bipolar I and bipolar II disorder are treated with a class of medication called mood stabilizers. Because the use of SSRI antidepressant medication may induce hypomania in bipolar individuals, it is only prescribed once a person is on an effective, stable dose of a mood stabilizer. In addition, those with bipolar I disorder with psychotic symptoms might require antipsychotic medication. It is common for a physician to prescribe multiple medications to treat the different symptoms of bipolar disorder.
  • Psychotherapy: Individual or group therapy services can help people with bipolar disorder learn skills to cope with their mood symptoms, improve their interpersonal interactions, and understand their experience of the disorder better. Evidence-based therapy treatments for bipolar disorder include cognitive behavioral therapy and interpersonal and social rhythm therapy.
  • Hospitalization: Both manic and depressive episodes can trigger suicidal ideation or behavior. Hospitalization might be necessary to stabilize medications or keep someone safe while they are in a suicidal crisis. Bipolar II does not require hospitalization.

Bipolar disorder often requires long-term treatment. Even once mood symptoms have stabilized, ongoing treatment is essential to prevent relapse. Medication management can reduce the risk for future manic, hypomanic, or depressive episodes.

In addition, therapy is most productive when the client is not undergoing an immediate crisis. Therapy services provided when an individual is stable are important for long-term improvement.

Prevention is an important piece of treatment for both types of the disorder. There is evidence that manic episodes damage the gray matter in the brain, destroying brain cells and affecting the temporal lobe and cerebellum (the parts of the brain associated with memory and coordination).

It is essential that clients bring any concerns related to ongoing medication or therapy to their treatment team and not change or stop a medication without supervision from the prescribing physician.

Cyclothymic Disorder: Bipolar III Disorder

In addition to bipolar I and bipolar II disorder, cyclothymic disorder can consist of hypomanic and depressive symptoms. Colloquially, cyclothymic disorder is sometimes referred to as “bipolar III disorder.” This diagnosis consists of ongoing hypomanic and depressive symptoms that do not meet the diagnostic criteria for a hypomanic or depressive episode.

For a diagnosis of cyclothymic disorder, an individual might have some depressive symptoms, such as low mood or loss of interest in activities, but the symptoms do not meet the diagnostic criteria for a major depressive episode. They also experience hypomanic symptoms, such as racing thoughts or decreased need for sleep, but they do not experience a full hypomanic episode. This could be because the number of symptoms does not meet criteria or the duration of the episodes is too short for a diagnosis of bipolar I or bipolar II disorder.

Coping With Bipolar Disorder

Typically, individuals with bipolar disorder will experience one to two episodes per year, but those who experience “rapid cycling” will have four or more episodes in a twelve-month period.

Being in tune with your feelings and recognizing if symptoms are increasing is an important part of living with bipolar disorder. Noticing that an episode might be coming, managing stress levels, and identifying and avoiding things that trigger episodes can help manage symptoms and maintain stability.

Having a treatment team made up of professionals that you trust is important for managing symptoms. Open, honest communication about your symptoms and stressors is an essential part of treatment.

Mood disorders, including bipolar I and bipolar II disorder, are steeped in stigma, but both conditions are highly treatable. Individuals with these disorders can receive effective treatment, stabilize, and lead fulfilling lives.

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