Tuesday, June 19, 2007

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."


StevePocetaMD said...

Thanks. Besides mood changes, I sometimes think that a very mild form of bipolar disease can show up with just insomnia, and can be treated with medications for bipolar disease.
The picture is great--it's amazing that we are starting to figure out how the genes cause a cell to basically keep time, and then those cells control the 24 hour cycle of the whole person.

StevePocetaMD said...

By the way, you are tagged, see:


Michael Rack, MD said...

thank you