Bipolar Disorder

Learning Objectives

  • Describe the symptoms and risk factors of bipolar disorder
  • Examine the epidemiology and etiology of bipolar disorder

Bipolar Mood Disorders

Three major types of bipolar disorder are described by the DSM-5 (APA, 2013): bipolar I, bipolar II, and cyclothymia. Bipolar I disorder (BD I), which was previously known as manic depression, is characterized by a single or recurrent manic episode. A person with bipolar disorder often experiences mood states that vacillate between depression and mania; that is, the person’s mood is said to alternate from one emotional extreme to the other (in contrast to unipolar, which indicates a persistently sad mood). A depressive episode is not necessary but commonly present for the diagnosis of bipolar I disorder.

Bipolar I, Bipolar II, and Cyclothymic Disorder

Bipolar II disorder is characterized by single (or recurrent) hypomanic episodes and depressive episodes, instead of the more severe manic episodes characteristic of bipolar I disorder.

Another type of bipolar disorder is cyclothymic disorder, characterized by numerous and alternating periods of hypomania and depression, lasting at least two years. To qualify for cyclothymic disorder, the periods of depression cannot meet the full diagnostic criteria for a diagnosis of major depressive disorder; the person must experience symptoms at least half the time with no more than two consecutive, symptom-free months, and the symptoms must cause significant distress or impairment.

A cartoon drawing of two figures. One figure has many speech bubbles around him while the other figure isn't speaking at all.

Figure 1. Being abnormally talkative is different from just having an outgoing personality.


To be diagnosed with bipolar disorder (BD), a person must have experienced a manic episode at least once in their life, or a hypomanic episode for bipolar II. According to the DSM-5, a manic episode is characterized as a “distinct period of abnormally and persistently elevated, expansive, or irritable mood and abnormally and persistently increased activity or energy lasting at least one week” that lasts most of the time each day (APA, 2013, p. 124).

During a manic episode, some experience a mood that is almost euphoric and they may become excessively talkative, sometimes spontaneously starting conversations with strangers; others become excessively irritable and complain or make hostile comments. An individual may talk loudly and rapidly, exhibiting flight of ideas: abruptly switching from one topic to another. Manic episodes make individuals very distracted, which can make a conversation very difficult.

Individuals with BD may exhibit grandiosity, in which they experience inflated but unjustified self-esteem and self-confidence. For example, they might quit a job in order to “strike it rich” in the stock market, despite lacking the knowledge, experience, and capital for such an endeavor. They may take on several tasks at the same time (e.g., several time-consuming projects at work) and yet show little, if any, need for sleep; some may go for days without sleep. Patients may also recklessly engage in pleasurable activities that could have harmful consequences, including spending sprees, reckless driving, making foolish investments, excessive gambling, or engaging in sexual encounters with strangers (APA, 2013).

During a manic episode, individuals usually feel as though they are not ill and do not need treatment. However, the reckless behaviors that often accompany these episodes—which can be antisocial, illegal, or physically threatening to others—may require involuntary hospitalization (APA, 2013). Some patients with bipolar disorder will experience a rapid-cycling subtype, which is characterized by at least four manic episodes (or some combination of at least four manic and major depressive episodes) within one year.

Manic or Hypomanic Episode

The core criterion for a manic or hypomanic episode is a distinct period of abnormally and persistently euphoric, expansive, or irritable mood and persistently increased goal-directed activity or energy. The mood disturbance must be present for one week or longer in mania (unless hospitalization is required) or four days or longer in hypomania. Concurrently, at least three of the following symptoms must be present in the context of euphoric mood (or at least four in the context of irritable mood):

  1. inflated self-esteem or grandiosity
  2. increased goal-directed activity or psychomotor agitation
  3. reduced need for sleep
  4. racing thoughts or flight of ideas
  5. distractibility
  6. increased talkativeness
  7. excessive involvement in risky behaviors

Manic episodes are distinguished from hypomanic episodes by their duration and associated impairment. Whereas manic episodes must last one week and are defined by a significant impairment in functioning, hypomanic episodes are shorter and not necessarily accompanied by impairment in functioning. Although major depressive episodes are common in bipolar disorder, they are not required for a diagnosis (APA, 2013).

In addition to experiencing a manic episode, the diagnosis should not be explained by substance abuse, other medical conditions, schizoaffective disorder, or be superimposed on schizophrenia, schizophreniform disorder, delusional disorder, or other type of schizophrenic disorders (DSM-5-TR). The diagnosis can be specified as having anxious distress, mixed features, rapid cycling, melancholic features, atypical features, catatonia, peripartum onset, seasonal pattern, or mood-congruent or mood-incongruent psychotic features.

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What’s the difference between bipolar I and bipolar II disorder?

Watch It

This video explains some of the common features of bipolar disorders, including causes and common treatment methods.

You can view the transcript for “Bipolar disorder (depression & mania) – causes, symptoms, treatment & pathology” here (opens in new window).

Risk Factors for Bipolar Disorder

Bipolar disorder is considerably less common than major depressive disorder. In the United States, one out of every 167 people meets the criteria for bipolar disorder each year, and one out of 100 meets the criteria within their lifetime (Merikangas et al., 2011). The rates of BD are higher in men than in women, and about half of those with this disorder report onset before the age of 25 (Merikangas et al., 2011). Around 90% of those with bipolar disorder have a comorbid disorder, most often an anxiety disorder or a substance abuse problem. Unfortunately, close to half of the people suffering from bipolar disorder do not receive treatment (Merikangas & Tohen, 2011). Suicide rates are extremely high among those with bipolar disorder: around 36% of individuals with this disorder attempt suicide at least once in their lifetime (Novick, Swartz, & Frank, 2010), and between 15–19% complete suicide (Newman, 2004).

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Epidemiology of Bipolar Disorders

Bipolar disorder is the sixth leading cause of disability worldwide and has a lifetime prevalence of about 1%-3% in the general population. However, a reanalysis of data from the National Epidemiological Catchment Area survey in the United States suggested that 0.8% of the population experience a manic episode at least once (the diagnostic threshold for Bipolar I) and a further 0.5% have a hypomanic episode (the diagnostic threshold for bipolar II or cyclothymia). Including sub-threshold diagnostic criteria, such as one or two symptoms over a short time period, an additional 5.1% of the population, adding up to a total of 6.4%, were classified as having a bipolar spectrum disorder. A more recent analysis of data from a second U.S. National Comorbidity Survey found that 1% met lifetime prevalence criteria for Bipolar I, 1.1% for Bipolar II, and 2.4% for subthreshold symptoms.

The lifetime prevalence rate of bipolar spectrum disorders in the general U.S. population is estimated at approximately 4.4%, with BD I constituting about 1% of this rate (Merikangas et al., 2007). Prevalence estimates, however, are highly dependent on the diagnostic procedures used (e.g., interviews versus self-report) and whether or not sub-threshold forms of the disorder are included in the estimate. BD often co-occurs with other psychiatric disorders. Approximately 65% of people with BD meet diagnostic criteria for at least one additional psychiatric disorder, most commonly anxiety disorders and substance use disorders (McElroy et al., 2001). The co-occurrence of BD with other psychiatric disorders is associated with poorer illness course, including higher rates of suicidality (Leverich et al., 2003).

A recent cross-national study sample of more than 60,000 adults from 11 countries, estimated the worldwide prevalence of BD at 2.4%, with BD I constituting 0.6% of this rate (Merikangas et al., 2011). In this study, the prevalence of BD varied somewhat by country. Whereas the United States had the highest lifetime prevalence (4.4%), India had the lowest (0.1%). Variation in prevalence rates was not necessarily related to socioeconomic status (SES), as in the case of Japan, a high-income country with a very low prevalence rate of BD (0.7%).

With regard to ethnicity, data from studies not confounded by SES or inaccuracies in diagnosis are limited, but available reports suggest rates of BD among European Americans are similar to those found among African Americans (Blazer et al., 1985) and Hispanic Americans (Breslau, Kendler, Su, Gaxiola-Aguilar, & Kessler, 2005). Another large community-based study found that although prevalence rates of mood disorders were similar across ethnic groups, Hispanic Americans and Black Americans with a mood disorder were more likely to remain persistently ill than European Americans (Breslau et al., 2005). Compared with European Americans with BD, Black Americans tend to be underdiagnosed for BD (and over-diagnosed for schizophrenia) (Kilbourne, Haas, Mulsant, Bauer, & Pincus, 2004; Minsky, Vega, Miskimen, Gara, & Escobar, 2003), and Hispanic Americans with BD have been shown to receive fewer psychiatric medication prescriptions and specialty treatment visits (Gonzalez et al., 2007). Misdiagnosis of BD can result in the underutilization of treatment or the utilization of inappropriate treatment, and thus profoundly impact the course of illness.

As with major depressive disorder, adolescence is known to be a significant risk period for BD; mood symptoms start by adolescence in roughly half of BD cases (Leverich et al., 2007; Perlis et al., 2004). Longitudinal studies show that those diagnosed with BD prior to adulthood experience a more pernicious course of illness relative to those with adult-onset, including more episode recurrence; higher rates of suicidality; and profound social, occupational, and economic repercussions (e.g., Lewinsohn, Seeley, Buckley, & Klein, 2002). The prevalence of BD is substantially lower in older adults compared with younger adults (1% vs. 4%) (Merikangas et al., 2007).

Etiology of Bipolar Disorders

Although there have been important advances in research on the etiology, course, and treatment of BD, there remains a need to understand the mechanisms that contribute to episode onset and relapse. There is compelling evidence for biological causes of BD, which is known to be highly heritable (McGuffin, Rijsdijk, Andrew, Sham, Katz, & Cardno, 2003). Genetic influences are believed to account for 73–93% of the risk of developing the disorder. For Bipolar I, the rate at which identical twins (same genes) will both have Bipolar I (concordance) is around 40%, compared to about 5% in fraternal twins. The high rate of heritability demonstrates that BD could fundamentally be a biological phenomenon. However, variability is high in the course of BD, both within a person across time and across people (Johnson, 2005). The triggers that determine how and when this genetic vulnerability is expressed are not yet understood; however, there is evidence to suggest that psychosocial triggers may play an important role in BD risk (e.g., Johnson et al., 2008; Malkoff-Schwartz et al., 1998).

A stressed-looking person holding their head.

Figure 2. While there is high hereditability in BD, psychosocial triggers are thought to play an important role in developing the disorder.

In addition to the genetic contribution, biological explanations of BD have also focused on brain function. Many of the studies using fMRI techniques to characterize BD have focused on the processing of emotional stimuli based on the idea that BD is fundamentally a disorder of emotion (APA, 2000). Findings have shown that regions of the brain thought to be involved in emotional processing and regulation are activated differently in people with BD relative to healthy controls (e.g., Altshuler et al., 2008; Hassel et al., 2008; Lennox, Jacob, Calder, Lupson, & Bullmore, 2004).

However, there is little consensus as to whether a particular brain region becomes more or less active in response to an emotional stimulus among people with BD compared with healthy controls. Mixed findings are in part due to samples consisting of participants who are at various phases of illness at the time of testing (manic, depressed, or inter-episode). Sample sizes tend to be relatively small, making comparisons between subgroups difficult. Additionally, the use of a standardized stimulus (e.g., facial expression of anger) may not elicit a sufficiently strong response. Personally engaging stimuli, such as recalling a memory, may be more effective in inducing strong emotions (Isacowitz, Gershon, Allard, & Johnson, 2013).

Within the psychosocial level, research has focused on the environmental contributors to BD. A series of studies show that environmental stressors, particularly severe stressors (e.g., loss of a significant relationship), can adversely impact the course of BD. People with BD have a substantially increased risk of relapse (Ellicott, Hammen, Gitlin, Brown, & Jamison, 1990) and suffer more depressive symptoms (Johnson, Winett, Meyer, Greenhouse, & Miller, 1999) following a severe life stressor. In surveys, 30–50% of adults diagnosed with bipolar disorder report traumatic/abusive experiences in childhood, which is associated with earlier onset, a higher rate of suicide attempts, and more co-occurring disorders such as post-traumatic stress disorder. Interestingly, positive life events can also adversely impact the course of BD. People with BD suffer more manic symptoms after life events involving the attainment of a desired goal (Johnson et al., 2008). Such findings suggest that people with BD may have a hypersensitivity to rewards.

Evidence from the life stress literature has also suggested that people with mood disorders may have a circadian vulnerability that renders them sensitive to stressors that disrupt their sleep or rhythms. According to social zeitgeber theory (Ehlers, Frank, & Kupfer, 1988; Frank et al., 1994), stressors that disrupt sleep or that disrupt the daily routines that entrain the biological clock (e.g., meal times) can trigger episode relapse. Consistent with this theory, studies have shown that life events that involve a disruption in sleep and daily routines, such as overnight travel, can increase bipolar symptoms in people with BD (Malkoff-Schwartz et al., 1998).

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Watch It

This video addresses common myths about bipolar disorder:

  1. There are only manic or depressive episodes in bipolar disorder.
  2. Bipolar II is a “milder” form of bipolar disorder.
  3. Mood swings during the day mean you have bipolar disorder.
  4. All bipolar patients have mania.
  5. People with bipolar disorder are unreliable.

You can view the transcript for “5 misunderstandings about Bipolar Disorder” here (opens in new window).

Treatment for Bipolar Disorder

Psychotherapy aims to assist a person with bipolar disorder in accepting and understanding their diagnosis, coping with various types of stress, improving their interpersonal relationships, and recognizing prodomal symptoms before full-blown recurrence. Cognitive behavioral therapy, family-focused therapy, and psychoeducation have the most evidence for efficacy in regard to relapse prevention, while interpersonal and social rhythm therapy and CBT appear the most effective in regard to residual depressive symptoms. Most studies have been based only on Bipolar I, however, and treatment during the acute phase can be a particular challenge. Some clinicians emphasize the need to talk with individuals experiencing mania to develop a therapeutic alliance in support of recovery.


Lithium (Lithobid, Eskalith) is effective at stabilizing mood and preventing the extreme highs and lows of bipolar disorder. Periodic blood tests are required because lithium can cause thyroid and kidney problems. Common side effects include restlessness, dry mouth, and digestive issues. Lithium levels should be monitored carefully to ensure the best dosage and watch for toxicity. Lithium is used for continued treatment of bipolar depression and for preventing relapse. There is evidence that lithium can lower the risk of suicide but the FDA has not granted approval specifically for this purpose.

Other mood-stabilizing medications and anticonvulsants (generally used to treat seizures) are recommended for treating bipolar disorder. Common side effects include weight gain, dizziness, and drowsiness. But sometimes, certain anticonvulsants cause more serious problems, such as skin rashes, blood disorders or liver problems.

Valproic acid and carbamazepine are used to treat mania. These drugs, also used to treat epilepsy, were found to be as effective as lithium for treating acute mania. They may be better than lithium in treating the more complex bipolar subtypes of rapid cycling and dysphoric mania.

Lamotrigine is used to delay occurrences of Bipolar I. Lamotrigine does not have FDA approval for treatment of the acute episodes of depression or mania. Studies of lamotrigine for treatment of acute bipolar depression have produced inconsistent results.

Second-Generation Antipsychotics (SGAs)

Second-generation antipsychotics (SGAs) are commonly used to treat the symptoms of bipolar disorder and are often paired with other medications, including mood stabilizers. They are generally used for treating manic or mixed episodes. Second-generation antipsychotics (SGAs) are often prescribed to help control acute episodes of mania or depression. Finding the right medication is not an exact science; it is specific to each person. Currently, only quetiapine and the combination of olanzepine and fluoxetine (Symbax) are approved for treating bipolar depression. Regularly check with the FDA website, as side effects can change over time.

Standard Antidepressants

Antidepressants present special concerns when used in treating bipolar disorder, as they can trigger mania in some people. A National Institute of Mental Health (NIMH) study showed that taking an antidepressant in addition to a mood stabilizer is no more effective than using a mood stabilizer alone for Bipolar I. This is an essential area to review treatment risks and benefits.

The aim of management is to treat acute episodes safely with medication and work with the patient in long-term maintenance to prevent further episodes and optimize functioning using a combination of pharmacological and psychotherapeutic techniques. Hospitalization may be required especially with the manic episodes present in Bipolar I. This can be voluntary or (local legislation permitting) involuntary. Long-term inpatient stays are now less common due to deinstitutionalism, although these stays can still occur. Following (or in lieu of) a hospital admission, support services available can include drop-in centers, visits from members of a community mental health team or an Assertive Community Treatment team, supported employment, patient-led support groups, and intensive outpatient programs. These are sometimes referred to as partial-inpatient programs.

Key Takeaways: Bipolar Disorder


bipolar and related disorders: a group of mood disorders in which mania is the defining feature

bipolar disorder: mood disorder characterized by mood states that vacillate between depression and mania

Bipolar I: previously known as manic-depression, characterized by a single or recurrent manic episode

Bipolar II: single (or recurrent) hypomanic episodes and depressive episodes; manic episodes are less severe than in Bipolar I

flight of ideas: symptom of mania that involves an abruptly switching in conversation from one topic to another

hypomania: a mood disturbance similar to mania, but slightly less severe and

mania: state of extreme elation and agitation

manic episode: period in which an individual experiences mania, characterized by extremely cheerful and euphoric mood, excessive talkativeness, irritability, increased activity levels, and other symptoms