What are bipolar and related disorders?

Bipolar disorders sit between psychotic disorders and depressive disorders in how they are classified—and in some ways they share features with both. The defining characteristic is the occurrence of mood episodes that are clearly outside the normal range. Depending on the type, this may include manic episodes (periods of abnormally elevated or irritable mood with dramatically increased energy), hypomanic episodes (a less severe version of mania), and depressive episodes (periods of persistent low mood and loss of energy or interest).

Bipolar disorders are not simply a matter of being "up and down" or moody. During a full manic episode, a person's behavior, judgment, and sense of self can be dramatically altered—sometimes to a degree that requires hospitalization. During depressive episodes, the same person may struggle to get out of bed. The contrast can be disorienting and exhausting for the person experiencing it and for those around them.

Types of bipolar and related disorders

Bipolar I Disorder

Defined by the presence of at least one manic episode—a distinct period of abnormally elevated, expansive, or irritable mood, combined with increased energy or activity, lasting at least one week (or less if hospitalization was needed). Depressive episodes are common but are not required for the diagnosis. The manic episode must cause marked impairment or include psychotic features, and must not be caused by substances or a medical condition.

Bipolar II Disorder

Requires at least one hypomanic episode and at least one major depressive episode—but no history of a full manic episode. Hypomania is a distinct but less severe elevation in mood and energy that does not cause the level of impairment seen in mania and does not involve psychosis. Bipolar II is often misdiagnosed as depression because the depressive episodes tend to be more prominent and the hypomanic periods may not be recognized as part of the illness.

Cyclothymic Disorder

A pattern of chronic mood instability involving numerous periods of hypomanic symptoms and depressive symptoms over at least two years (one year in children and adolescents). Crucially, these symptoms do not meet the full criteria for a hypomanic or depressive episode. Cyclothymic disorder represents a milder but persistent form of mood cycling that can still cause meaningful disruption to daily life.

Other specified and unspecified bipolar disorders

Some people experience bipolar-like symptoms that cause distress or impairment but do not fit neatly into one of the above categories. This may include short-duration hypomanic episodes, hypomania with too few symptoms to meet full criteria, or brief cyclothymia. These presentations are still clinically significant and warrant assessment and support.

Substance/medication-induced and medically caused bipolar disorders

Manic or hypomanic symptoms can be triggered by substance use, withdrawal, or certain medications—as well as by underlying medical conditions such as hyperthyroidism or neurological conditions. In these cases, treating the underlying cause is central to managing the mood symptoms.

Understanding the mood episodes

The different types of bipolar disorder are defined by which mood episodes occur. Understanding what each looks like helps in recognizing them.

Manic episode

A distinct period—lasting at least a week—of abnormally and persistently elevated, expansive, or irritable mood, combined with increased activity or energy. During this time, three or more of the following are present (four if the mood is mainly irritable):

Inflated self-esteem or grandiosity—feeling unusually powerful, important, or capable
Decreased need for sleep—feeling rested after only a few hours, or not sleeping at all
More talkative than usual, or speech that feels pressured and hard to interrupt
Racing thoughts or a rapid flow of ideas jumping from one to the next
Distractibility—attention pulled easily to irrelevant things
Increased goal-directed activity or restless physical agitation
Excessive involvement in risky activities—spending sprees, sexual behavior, or reckless decisions that are out of character

A manic episode causes marked impairment in functioning, may require hospitalization, and may involve psychotic features such as delusions or hallucinations.

Hypomanic episode

Hypomania involves the same kinds of symptoms as mania—elevated or irritable mood, increased energy, reduced need for sleep, increased talkativeness, racing thoughts—but at a lower intensity. It lasts at least four days and is noticeable to others, but does not cause the severe impairment associated with mania and does not involve psychosis or require hospitalization. Some people find hypomanic periods feel productive or even enjoyable, which is one reason bipolar II and cyclothymia can go unrecognized.

Major depressive episode

A period of at least two weeks characterized by persistent low mood or loss of interest or pleasure in nearly all activities, accompanied by other symptoms such as changes in sleep, appetite, energy, concentration, and thoughts of death or suicide. In the context of bipolar disorder, depressive episodes are often the most frequent and most disabling part of the illness.

Signs to look out for

Bipolar disorders are sometimes difficult to recognize because the episodes can look very different from each other, and because people often seek help during a depressive episode without mentioning—or being asked about—past periods of elevated mood. Across conditions, signs worth paying attention to include:

Periods of unusually high energy, reduced need for sleep, and racing thoughts that are clearly different from normal
Behavior during elevated mood that feels out of character—spending money recklessly, making impulsive decisions, or talking much more than usual
Recurring episodes of depression, especially if they alternate with periods of elevated mood or energy
Mood swings that seem cyclical or patterned over months or years
A history of depression that has not fully responded to antidepressants alone
A family history of bipolar disorder, which significantly raises a person's own risk

What helps

Bipolar disorders are lifelong conditions, but they are treatable. Most people with bipolar disorder are able to live full and productive lives with appropriate support. Effective approaches include:

Mood stabilizers—medications such as lithium, valproate, and lamotrigine are cornerstone treatments that help prevent episodes and reduce their severity
Atypical antipsychotics—a range of medications used to manage acute episodes and as longer-term maintenance treatment
Psychotherapy—cognitive behavioral therapy, family-focused therapy, and psychoeducation all help people understand the disorder, recognize early warning signs, and manage triggers
Regular routines—stable sleep, exercise, and daily structure help regulate mood and reduce episode frequency
Monitoring and early action—learning to recognize the early signs of a mood episode and having a plan to act quickly can prevent a full relapse
Avoiding substances—alcohol and recreational drugs can destabilize mood and interact with medications

Medication is typically central to managing bipolar disorders—particularly Bipolar I. Stopping medication is a common trigger for relapse, even when someone has been well for a long time. Any changes to treatment should be made with a psychiatrist.

When to seek help

If you or someone you know is experiencing a period of elevated mood with significantly reduced sleep, impulsive behavior, or racing thoughts—especially if this has happened before—it is worth seeking a medical assessment promptly. Manic episodes can escalate quickly and carry real risks.

If depression is the main concern, it is still worth asking about any periods of unusually high mood or energy in the past, as this information changes how the condition is understood and treated. Giving antidepressants without a mood stabilizer to someone with unrecognized bipolar disorder can trigger a manic episode.

A GP or psychiatrist can carry out an assessment and, if appropriate, refer for specialist support.

Bipolar and related disorders