Mental illness characterized by the alternation of manic and depressive states. Depression is the more common symptom, and many patients experience only a brief period of overoptimism and mild euphoria during the manic phase. The condition, which seems to be inheritable, probably arises from malregulation of the amines norepinephrine, dopamine, and 5-hydroxytryptamine. It is most commonly treated with lithium carbonate.

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In Medicine

• Bipolar disorder and its subtypes:
• Bipolar I
• Bipolar II
• Cyclothymia
• Bipolar cell, a second order neuron of the retina.

In charitable organisation

MDF The BiPolar Organisation - A UK based charitable organisation

In Electronics and electrical engineering

• Bipolar junction transistor, electronic device.
• BiCMOS, the integration of bipolar junction transistors and CMOS technology into a single device.
• A loudspeaker design which has transducers on the front and the rear of the enclosure.
• Nickname for the Milwaukee Road class EP-2 electric locomotives.
• bipolar encoding, a type of line code used in telecommunication.
• bipolar high-voltage direct current transmission

In Science

• Bipolar nebula, a two-lobed, axi ally symmetric nebula
• Bipolar outflow, outflow of ejected materials from both poles of a star.
• Bipolar political system, a system where two political powers are equally matched.

In Mathematics

• Polar set, sometimes called a bipolar set, is the polar of a polar set.
• Bipolar coordinates, a type of orthogonal coordinates based on the Apollonian circles.

In Pop culture

• Bi-Polar (album), an album by Vanilla Ice.
• Bi-Polar (Chilli Album), an album by Rozonda Thomas, Chilli of TLC (band)