Features of bipolar disorder

The mood episodes of bipolar disorder are mania, hypomania and depression.

Acute mania is a distinct period with an abrupt onset of symptoms, including abnormally and persistently elevated, expansive or irritable mood, accelerated speech, racing thoughts with flight of ideas, increased activity and reduced sleep requirements. Patients may develop grandiose ideas, act recklessly (including increased spending), and have increased sexual drive and activity. Patients who have psychosis are considered to have a severe presentation. To diagnose mania, symptoms must be present for most of the day, cause marked functional impairment and last for at least 1 week. However, a diagnosis of acute mania can be made with symptoms of any duration if the patient requires admission to hospital because of their symptoms.

A hypomanic episode is characterised by symptoms similar to those of a manic episode, but is differentiated from a manic episode by less severe symptoms that do not impair functioning. The symptoms last at least 4 consecutive days and are present for most of the day. People with hypomania do not experience psychotic symptoms.

Depressive episodes last for at least 2 weeks and must include a depressed mood, or a loss of interest or pleasure, for most of the day. The episode must cause significant distress or impair the person’s functioning; during depressive episodes, there is a high risk of suicide. While most symptoms overlap with those of major depression, patients with bipolar depression are more likely to have atypical depressive features (eg excessive sleeping or eating), psychomotor slowing, psychotic features or mixed features (ie manic or hypomanic features interspersed in the depression). Most patients experience at least one depressive episode before developing a first episode of mania or hypomania. Depressive episodes are the predominant mood episode for most patients with bipolar disorder, especially those with bipolar II disorder. Patients with bipolar disorder also frequently experience periods of subthreshold depressive symptoms between the major mood episodes.

Mixed features describes the simultaneous experience of symptoms opposite to the predominant state (eg during a manic episode, patients also experience depressive symptoms). Mixed features can occur during a manic, hypomanic or depressive episode.

Rapid cycling bipolar disorder can occur in some patients, in which at least 4 mood episodes are experienced in a 12-month period (ie manic, hypomanic or depressive episodes). This is the most difficult to treat of all bipolar disorder presentations.