Sleep and Bipolar Disorder

Sleep disturbance is a cardinal feature of bipolar disorder. During acute mania, patients exhibit markedly reduced sleep time and report a reduced need for sleep. The reduced need for sleep can be further defined as the “ability to maintain energy without sufficient sleep” (Plante and Winkelman, 2008). Even when euthymic, sleep disturbance is common (Harvey 2008). In a recent study, 55% of euthymic bipolar patients had chronic insomnia (Harvey et al 2005). Both insomnia and hypersomnia have been reported in patients with bipolar depression (Harvey 2008). Children with bipolar disorder (who often display ultradian rapid cycling rather than distinct mood episodes) exhibit reduced sleep efficiency and frequent nocturnal awakenings (Mehl et al 2006).

Both homeostatic and circadian sleep abnormalities are thought to play a role in bipolar disorder (Plante and Winkelman 2008).

Polysomnographic studies of unmedicated manic panics have found shortened total sleep time, shortened REM latency, and increased time awake in bed (Plante and Winkelman 2008).

**Harvey AG. Sleep and circadian rhythms in bipolar disorder: seeking synchrony, harmony, and regulation. Am J Psychiatry 2008;165(7):820-9.**


Harvey AG, Schmidt DA, Scarna A, Semler CN, Goodwin GM. Sleep-related functioning in euthymic patients with bipolar disorder, patients with insomnia, and subjects without sleep problems. Am J Psychiatry 2005;162(1):50-7.

Mehl RC, O’Brien LM, Jones JH, Dreisbach JK. Correlates of sleep and pediatric bipolar disorder. Sleep 2006;29(2):193-7.

**Plante DT, Winkelman JW. Sleep disturbance in bipolar disorder: therapeutic implications. Am J Psychiatry 2008;165(7):830-43.**

The above is excerpted from an article I wrote on Sleep Disorders and Mental Illness for Medlink Neurology.

Circadian Rhythms

USAToday has a nice article today about circadian rhythms, with the final part of the article focusing on the possible role of circadian rhythm disturbance in bipolar disorder:

In people, circadian rhythm disorders can trigger serious problems, notably depression. Seasonally affective disorder is a winter depression tied to a lack of the sunlight cues that trigger the SCN into proper rhythm.
Also, there are indications that bipolar disorder also involves circadian problems, McClung says. This disorder causes unusual shifts in mood and energy, with episodes varying between extremes and afflicting some 5.7 million people nationwide, according to the National Institute of Mental Health. "People might sleep all the time or not sleep at all," says McClung. Body temperatures and hormone levels similarly race, all pointing to a body clock with its springs missing.
At the Cold Harbor conference, McClung presented a mouse engineered to lack a specific clock gene which "looks as close to a bipolar person in a manic state as we can determine in a mouse," she says. The manic mice are hyperactive, sleep little, disregard signs of predators and voraciously consume cocaine.
For medical research, the most intriguing thing about the manic mice is that lithium, which human bipolar patients take to treat their illness, cuts their symptoms. "We don't know why lithium works, and we hope the mouse gives us an opportunity to explore its mechanism," McClung says.
Opening up the mechanism by which clock genes work, or don't work, is the task before scientists today, McClung adds. "Everyone on this planet has a 24-hour internal clock, and it is deeply ingrained in our biology," she says. "If we lived on a different planet, we'd have a different rhythm — that's how fundamental they are."