Definition of Manic-depressive disorder

Bipolar disorder is a psychiatric condition defined as recurrent episodes of significant disturbance in mood. These disturbances can occur on a spectrum that ranges from debilitating depression to unbridled mania. Individuals suffering from bipolar disorder typically experience fluid states of mania, hypomania or what is referred to as a mixed state in conjunction with depressive episodes. These clinical states typically alternate with a normal range of mood. The disorder has been subdivided into bipolar I, bipolar II and cyclothymia, with both bipolar I and bipolar II potentially presenting with rapid cycling.