ICD-10 code: F31.81
Bipolar II Disorder (BPII) is part of a cluster of diagnoses called the bipolar and related disorders. Bipolar and related disorders are a group of psychiatric conditions that include:
These disorders are characterized by the occurrence of discrete mood episodes, including the presence of mania (in bipolar I disorder), hypomania (in bipolar II disorder), or hypomanic symptoms that do not meet full diagnostic criteria for hypomania or mania (in cyclothymic disorder).
An individual experiencing mania or hypomania may experience a significantly decreased need for sleep (e.g., feeling rested after only a few hours of sleep), inflated self-esteem or grandiosity, an increase in goal-directed activity (e.g., starting new projects at work or home), pressured speech, and other symptoms. Most individuals with bipolar and related disorders also experience discrete periods of depression, which are generally characterized by sadness or loss of interest, fatigue, difficulty concentrating, and/or sleep or appetite disturbance. To be diagnosed with a bipolar-related disorder, these mood symptoms must represent a clear change from normal (baseline) functioning.
The bipolar and related disorders differ from each other in the duration, severity, and types of symptoms that the individual experiences. Individuals with bipolar I disorder experience discrete manic episodes, in which manic symptoms last a week or longer, require hospitalization, or are accompanied by psychotic symptoms. A history of a major depressive episode is not required for a bipolar I diagnosis, but such an episode will occur in the majority of individuals with bipolar I disorder. Individuals with bipolar II disorder experience hypomanic episodes, in which manic symptoms last at least four days, are not severe enough to cause marked impairment or necessitate hospitalization, and are not accompanied by psychotic features. A bipolar II diagnosis requires a history of at least one major depressive episode. Finally, individuals with cyclothymic disorder experience numerous periods of hypomanic symptoms and depressive symptoms that do not meet criteria for hypomanic and depressive episodes, respectively.
BPII is a psychiatric disorder that affects approximately 1% of adults. BPIIis characterized primarily by the presence of hypomanic and major depressive episodes. Hypomanic episodes are distinct periods of at least four days in which mood is abnormally and persistently elevated or irritable, along with other symptoms such as an increase in goal-directed activity or energy.
During the hypomanic episode, at least three of the following symptoms occur (four symptoms if the mood is only irritable):
Hypomanic episodes are distinguished from manic episodes primarily by severity; by definition, hypomanic episodes are not severe enough to cause marked impairment or necessitate hospitalization. If impairment is severe or hospitalization is warranted, or if psychotic features are present, BPI is the more appropriate diagnosis.
BPII also requires a history of at least one major depressive episode. Major depressive episodes are characterized primarily by depressed mood or loss of interest. To meet diagnostic criteria, the individual must also experience at least four of the following symptoms, which must occur with the depressed mood or loss of interest nearly every day for two weeks or longer:
Sometimes mixed episodes can occur, where the individual meets criteria for both a hypomanic episode and a major depressive episode concurrently. Typically, the individual with BPII will also have periods of euthymia, where no significant mood symptoms are present. However, euthymic periods occur less frequently and are often of a shorter duration in BPII compared to BPI.
BPII severity can range from mild to debilitating. In severe cases, BPII can lead to inability to work or attend school, particularly during depressive episodes, and can cause serious problems in interpersonal relationships. Many people with BPII also have other psychiatric conditions, most commonly personality disorders, substance abuse or dependence, and anxiety disorders.
BPII is characterized by abnormalities of brain function which are thought to contribute to symptoms. In particular, evidence points to hypoactivation in several regions of the prefrontal cortex, which are involved in executive functioning and regulation of emotion. Hyperactivation of limbic structures involved in emotion generation, including the amygdala, and reduced connectivity of the amygdala with frontal regions,have also been observed. The disorder has a genetic component, although having a genetic predisposition to BPII does not necessarily mean that someone will develop BPII.
BPII is generally thought to be a chronic disorder, but it can be managed effectively. BPII generally should not be managed in primary care; primary care management should occur only in consultation with a specialist.
Published treatment guidelines for bipolar disorder include those from the American Psychiatric Association (ApA), the Society of Clinical Psychology, and the National Institute for Clinical Excellence (NICE). NICE and ApA state that these guidelines should be applied to the treatment of both BPI andBPII. However, the guidelines also note that few studies have explicitly distinguished between BPI and BPII; the studies that do distinguish between the disorders more often include BPI samples. Therefore, caution is warranted when applying these guidelines, particularly with respect to managing hypomanic symptoms.
First Line Treatments
To manage severe mania symptoms or a mixed episode, combined pharmacological treatment with lithium plus an atypical antipsychotic such as olanzapine, risperdone, or quetiapine is the first-line treatment. For a less severe hypomanic episode, monotherapy with lithium, valproate, or an atypical antipsychotic may be sufficient. Short-term adjunctive treatment with a benzodiazepine may also be helpful.
In the case of a bipolar depressive episode, lithium or lamotrigine are considered first-line treatments. Antidepressant monotherapy is not recommended, as this can trigger hypomanic symptoms.
Augmentation of first-line pharmacological interventions with psychotherapy is also indicated. Psychological treatments with research support include:
Second Line Treatments
In cases of nonresponse to first-line treatment or "breakthrough" episodes despite continued pharmacological treatment, optimization of the medication dose should be the first intervention. During a depressive episode, augmentation with an antidepressant may be considered. Antidepressant-induced manic symptoms are less likely in BPII compared to BPI. Adjunctive medications to be considered may include:
Electroconvulsive therapy (ECT), in which small electrical currents are used to trigger a brief seizure, may also be provided as an augmentation strategy. ECT may be indicated if the individual is pregnant or in the case of a mixed episode.
Additional Treatments to Consider
Preliminary evidence suggests that the following strategies, while not a substitute for the more well-validated treatments described above, might be considered to assist with depressive symptoms. However, most of these treatments have not been evaluated in the context of BPII; therefore, the risk of triggering a manic episode should be carefully weighed against the potential benefits.