Kay Redfield Jamison Quote

Circadian rhythms are implicated in some of the symptoms of depression, such as early awakening and diurnal variation in mood. The possible importance of the circadian system in its pathogenesis is suggested by the capacity of experimental alterations in the timing of sleep and wakefulness to alter clinical state. Biological rhythms range in frequency from milliseconds to months or years. Most rhythmic disturbances identified in the symptoms of manic-depressive illness occur over the course of a day-that is, they are circadian rhythms-and are most apparent in the daily rest-activity cycle. The episodic recurrences of the illness, on the other hand, are usually infradian, oscillating over periods of months or years. Episodic mania and depression may also reflect disturbances in ultradian rhythms, those that oscillate more than once a day, which are common at the cellular level and in hormone secretion, as well as in such autonomic functions as circulation, blood pressure, respiration, heart rate, and in the cycles of sleep.