DEFINITION:
The phrase “bipolar disorder (BD)” refers to a mental illness characterized by cycles consisting of periods of depression alternating with periods of abnormally elevated mood, each cycle consisting of a variable amount of time lasting from a few days days to several weeks.
ETYMOLOGY:
The phrase BD was invented by the German psychiatrist Karl Leonhard (1904–1988) in his 1957 book, Aufteilung der endogenen Psychosen [Division of the Endogenous Psychoses] (English translation, 1979).
Ther phrase “BD was intended to replace the earlier phrase, “manic-depressive psychosis,” coined by the German psychiatrist Emil Kraepelin (1856–1926) in 1913.
The English term “bipolar” is attested from the early nineteenth century. It is formed from the two elements:
(1) The English prefix “bi-,” which derives, via Middle English, from the Classical Latin adverb bis, meaning “two” or “in two ways”; and
(2) The English adjective “polar,” which is attested from the mid-sixteenth century. It derives from the Medieval Latin adjective polaris, meaning the “of or relating to a pole.” Polaris, in turn, derives from the Classical Latin noun polus, poli, meaning the “end of an axis.”
The English noun “pole” is an allied form, which is attested from the fourteenth century. It derives separately, via the Middle English noun pool, from the same Classical Latin noun, polus.
For the etymology of the term “disorder,” see the Glossary entry, borderline personality disorder.
DISCUSSION:
Patients suffering from BD are whipsawed between depressed and elevated states of mind.
During the depressive phase (see the Glossary entry, depression), the patient’s negative mood leads to crying jags, the avoidance of eye contact, anxiety, and an increased risk of substance abuse, self-harm, and suicide.
During the manic phase, the patient’s positive or elevated mood may lead to abnormal energy levels, reduced need for sleep, giddiness, irritability, impulsivity, and heedlessness of the consequences of one’s actions.
The manic phases in a case of BD may vary in intensity. Less severe episodes of mania are sometimes referred to as “hypomania,” while more severe episodes may lead to full-blown psychosis (see Glossary entry, psychosis) in some cases.
Several subclassifications of BD are in common use, including “bipolar I” (at least one manic episode, with or without depression), “bipolar II” (at least one hypomanic episode, no full manic episode, and at least one major depressive episode), and “cyclothymia” (hypomanic episodes with depressive episodes that fall short of major depression).
The causes of BD are not well understood. However, it is likely that both genetic and environmental factors play a role in the etiology of the illness.