Bipolar 1 vs Bipolar 2: What’s the Difference?

Bipolar disorder is a mood disorder that can cause significant shifts in mood, energy, activity, sleep, and behavior. These changes can range from periods of unusually high energy and activity to episodes of significant depression. Bipolar I disorder and Bipolar II disorder are related but distinct diagnoses, and the biggest difference between them is the type of elevated mood episode a person experiences. Bipolar I involves mania, while Bipolar II involves hypomania and requires a history of major depressive episodes.

Both Bipolar I and Bipolar II are serious, treatable medical conditions. They can affect relationships, work, school, sleep, and overall quality of life, but with appropriate treatment and support, many people with bipolar disorder are able to live stable, fulfilling lives. This article explains the differences between Bipolar I and Bipolar II, including the diagnostic criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), common symptoms, and general approaches to treatment. This information is intended for education and is not a substitute for an evaluation by a qualified mental health professional.

Understanding Bipolar Disorder Types

Bipolar disorder was called manic-depressive illness in the past, reflecting the two ends of the mood spectrum that can occur. Today, clinicians understand bipolar disorders as a group of related conditions involving episodes of elevated mood, activity, and energy; depressive episodes; and periods when a person’s mood returns to their usual baseline, sometimes called euthymia. The pattern varies considerably from person to person.

The two diagnoses most people are referring to when they talk about bipolar disorder are:

• Bipolar I disorder: Defined by the occurrence of at least one manic episode. Major depressive episodes are common but are not required for the diagnosis.
• Bipolar II disorder: Defined by at least one hypomanic episode and at least one major depressive episode, without any history of a full manic episode.

There are also other diagnoses within the bipolar spectrum. Cyclothymic disorder, for example, involves extended periods of mood elevations and dips that do not meet the full criteria for hypomanic or major depressive episodes but still cause distress or impairment in functioning. The DSM-5-TR also includes other specified and unspecified bipolar and related disorders for presentations that do not fit neatly into the primary categories. This page focuses primarily on Bipolar I and Bipolar II because they are two of the most commonly discussed diagnoses and are often confused with one another.

DSM-5-TR Criteria: Bipolar I vs Bipolar II at a Glance

The DSM-5-TR provides the diagnostic criteria mental health professionals use to identify psychiatric disorders, including Bipolar I and Bipolar II disorder. Clinicians consider the specific symptoms, how long they last, how different they are from a person’s usual functioning, and how significantly they affect daily life. This helps distinguish mania and hypomania from the normal changes in mood and energy that everyone experiences.

A manic episode is a distinct period of unusually elevated, expansive, or irritable mood with increased energy or activity and other symptoms. It lasts at least one week, or any duration if hospitalization is necessary, and causes significant impairment, requires hospitalization, or involves psychosis. A hypomanic episode involves a similar but less severe change lasting at least four consecutive days. By definition, hypomania does not cause marked impairment, require hospitalization because of the episode, or involve psychosis.

Importantly, Bipolar I disorder can be diagnosed after a single qualifying manic episode. A person does not need to have multiple episodes or a history of depression. For Bipolar II disorder, both a qualifying hypomanic episode and a major depressive episode are required, with no history of mania. At the same time, normal emotional reactions, such as feeling especially happy after receiving a promotion or deeply sad after experiencing a loss, are not by themselves sufficient for a diagnosis of bipolar disorder. Clinicians consider the overall pattern, severity, duration, and impact of symptoms when making a diagnosis.

Mania vs Hypomania: How Elevated Moods Differ

Mania and hypomania share many symptoms, including decreased need for sleep, racing thoughts, increased energy, rapid or increased speech, greater confidence, increased activity, and impulsive behavior. The key difference is severity and impact on functioning.

Mania causes significant impairment and can become dangerous. From the outside, a person may seem very different from their usual self, talking rapidly or non-stop, jumping between topics, starting numerous projects, making unrealistic plans, spending impulsively, becoming unusually irritable, or behaving in ways that are clearly out of character. They may sleep very little without feeling tired. From the person’s perspective, mania may feel energizing, creative, productive, and even powerful. Some people experience an exaggerated sense of confidence or importance and may not recognize that their behavior has changed. In severe cases, mania can involve psychosis, such as hallucinations or delusional beliefs, and may require hospitalization.

Hypomania involves many of the same changes but is less severe. A person may sleep less, feel unusually energetic or confident, talk more, become more social, take on multiple projects, or feel exceptionally productive or creative. Others may notice that the person is more talkative, active, enthusiastic, or driven than usual. However, hypomania does not cause the marked impairment, hospitalization, or psychosis that can occur with mania. The person often may enjoy the experience and feel that they are functioning better than usual.

Everyone has periods of excitement, motivation, increased productivity, or strong emotions. What distinguishes mania or hypomania is the degree and persistence of the change from a person’s usual baseline, along with the combination of symptoms. For example, staying up late to finish an exciting project is not necessarily hypomania, but consistently sleeping only a few hours without feeling tired while also experiencing racing thoughts, unusually rapid speech, increased impulsivity, and behavior that is markedly different from one’s usual self may warrant an evaluation by a mental health professional.

Depression in Bipolar I and Bipolar II

Depression is sometimes a prevalent part of bipolar disorder. A major depressive episode generally involves at least two weeks of certain symptoms occurring more often than not, such as: depressed mood or loss of interest or pleasure, along with changes in sleep or appetite, fatigue, difficulty concentrating, feelings of worthlessness or guilt, changes in activity level, or thoughts of death or suicide. The symptoms must be significant enough to affect functioning or feel distressing, and cannot be better explained by another cause.

Major depressive episodes can occur in both Bipolar I and Bipolar II. However, a history of major depressive episodes is required for a diagnosis of Bipolar II, while it is not required for Bipolar I. People with Bipolar II also often spend more time experiencing depressive symptoms than they do hypomania. This can make the condition particularly difficult to recognize, especially when periods of hypomania are brief, rare, feel positive, or are not reported during an evaluation.

This is one reason Bipolar II can initially be mistaken for unipolar depression, also called major depressive disorder. If someone seeks treatment during a depressive episode but does not recognize or report previous periods of hypomania, the larger pattern can be missed. This distinction matters because treatment for bipolar depression can differ from treatment for unipolar depression, and antidepressants used without an appropriate bipolar treatment plan may contribute to mood destabilization in some people.

Both Bipolar I and Bipolar II are associated with an increased risk of suicidal ideation and suicide. According to the DSM-5-TR: the lifetime risk of suicide in people with bipolar disorder is approximately 20 to 30 times greater than in the general population, and 5 to 6% of people with bipolar disorder die by suicide.

Any thoughts of suicide or concern that you or a loved one  may not be able to stay safe should be taken seriously. If there is an immediate risk of harm, call 911 or go to the nearest emergency department. In the United States, you can also call or text 988 to reach the Suicide & Crisis Lifeline.

Why the Distinction Matters for Treatment and Daily Life

The distinction between Bipolar I and Bipolar II is more than a label. A history of mania, hypomania, and depression helps clinicians determine what symptoms need to be monitored and which treatments are most appropriate. For Bipolar I disorder, medication is generally a central part of treatment because of the potential severity and recurrence of manic episodes. Treatment should typically be continued even when a person is feeling well to reduce the risk of future episodes. It only takes one manic episode to undo years of hard work, as manic behaviors such as impulsive sexual activity, excessive spending, reckless behavior, or dangerous decision-making can have serious and lasting harmful consequences.

Medication selection also depends on the current phase of illness. Different medications have stronger evidence for treating acute mania, bipolar depression, or preventing future mood episodes. Treatment may include mood stabilizers, such as lithium, and/or atypical antipsychotics, with the specific medication chosen based on the person’s symptoms, history, side-effect profile, and other health considerations. Antidepressants may have a role for some people with bipolar depression, but they are used cautiously because they can contribute to mood switching or destabilization in some individuals. Medication decisions should therefore be individualized and guided by a clinician with experience treating bipolar disorder.

Psychotherapy can also be an important part of treatment. Cognitive behavioral therapy (CBT) can help people recognize patterns in thoughts and behaviors that affect mood. Other approaches, including interpersonal and social rhythm therapy, focus on maintaining consistent sleep and daily routines and recognizing early changes in mood. Learning to identify a person’s own warning signs can be particularly helpful for preventing or limiting future episodes.

The practical impact of bipolar disorder varies considerably from person to person. Someone with Bipolar I may experience periods when mania significantly disrupts work, relationships, finances, or daily functioning, while someone with Bipolar II may experience less disruption from hypomania but spend substantial amounts of time dealing with depression. Neither diagnosis alone determines how a person will function or what their future will look like.

With appropriate treatment, ongoing monitoring, and support, many people with either diagnosis are able to maintain relationships, work, pursue education, and enjoy meaningful lives.

Getting Help: Diagnosis, Safety, and Next Steps

It may be worth scheduling an evaluation with a psychiatrist or other qualified mental health professional if you have experienced distinct periods of unusually high energy, decreased need for sleep, racing thoughts, rapid speech, increased impulsivity, unusually elevated or irritable mood, and/or significant episodes of depression. It is particularly important to seek an evaluation if these changes have affected your relationships, work, school, finances, or ability to function safely.

A comprehensive evaluation may include screening tools and questionnaires, along with a detailed discussion of your current symptoms and history over time. A clinician may ask about previous periods of depression or elevated mood, sleep patterns, medications, substance use, medical conditions, family psychiatric history, and changes in functioning.

Screening for other conditions that can cause similar symptoms is also an important part of the process, and bloodwork may be ordered. With your permission, information from a partner or family member can sometimes be especially helpful, as people experiencing mania or hypomania may not recognize all of the changes that others have noticed.

Bipolar diagnoses can also change as a person’s presentation becomes clearer. For example, someone initially diagnosed with Bipolar II disorder may later meet criteria for Bipolar I disorder if they experience a full manic episode. A qualified clinician can help put symptoms into context and develop an individualized treatment plan. If you or someone you care about is experiencing severe mania, psychosis, suicidal thoughts, or another psychiatric emergency, seek immediate help through 911, the nearest emergency department, or 988 in the United States.

This article is intended for general educational purposes and is not a substitute for professional medical or psychiatric evaluation, diagnosis, or treatment. If you have concerns about your mood, sleep, energy, or behavior, speak with a qualified mental health professional.

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