Ultradian denotes biologic activities that recur in physiological cycles of 20 hours or less. They are independent of illumination factors.
The descriptive term ultradian is used in sleep research to describe individual stages of sleep that occur within intervals of an organism's circadian rhythm, and especially to refer to the 90 minute ultradian cycle in human sleep.
Some of the ultradian cyclings of the body are hormonal release, heart rate, thermoregulation, nostril dilation and appetite. The last involves rhythmic release of Neuropeptide Y (NPY) and Corticotropin-releasing hormone(CRH), stimulating and inhibiting appetite ultradian rhythms.
All forms of Bipolar Disorder have a defined biological nature, apparently stemming from a common genetic factor that leads to generational morbidity. Both twins studies, and general population studies show that there is an increased chance of developing a Bipolar Disorder when either a general mood disorder or a specific Bipolar disorder is present in family members. Further research is being conducted to discriminate any environmental factors that may also play a role in onset and severity of Bipolar disorder. The same kindling effect that is present with seizure disorders has been observed in early onset cases of Bipolar Disorder. Results are inconclusive at this time.
Ultradian states in Bipolar Disorder are different from rapid cycling, (having four or more mood episodes in a year). The term rapid cycling was defined prior to discovery of Ultradian mood states. Thus it can be misleading to think of these states as ultra rapid cycling, as this particular form of cycling is also described as a mixed state, and has not yet gained universal acceptance. Both terms are unable to capture the nature of this unique form of the Bipolar Disorder.
Ultradian cycling is characterized by more than four mood states within a year. Often these mood states occur within the space of a few weeks or even a single day. These oscillations, cycles, may last for several hours, a few days, or even weeks. While our current understanding looks to the presence of both states simultaneously, there are anecdotal cases where situational factors can produce distinct and separate periods of depression or mania/hypomania, switching back and forth. Because there is very little research into this particular form of cycling, the terminology is borrowed from the more established research into the formal Bipolar I or Bipolar II categories.
Ultradian Bipolar Disorder is productively treated by the same mood-stabilizing medications used with Bipolar I and II, though dosing may be difficult due to situational stress and other environmental factors.
Researchers are working to understand the brain chemistry basis of mood states in an effort to better diagnose and treat Bipolar Disorder. This research shows the promise of finding biological determinants for Ultradian mood states.
["Acute, rapid-cycle bipolar disorder" has also been used in recent studies involving the cycling of once daily (1d) to once hourly (1h). Minor "seizures" and "strokes" have also been found in these studies...]