Too Little Sleep Can Make Us Go Violent

Too Little Sleep Can Make Us Go Violent

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• Jun 28, 2008 at 5:04 AM
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Sleeping woman

Researchers have now discovered a few nights without enough sleep can do a lot more than make people tired, grouchy, or emotional, it can actually put the brain in to a primitive  'fight' or 'flight' state.

Volunteers of both men and women were given brain scans first and after two full days with no sleep. What scientists discovered was that the volunteers' brains seemed to rewire, re-directing activity from the calming and rational prefrontal cortex to the 'fear centre', the amygdala.

"It's almost as though, without sleep, the brain had reverted back to more primitive patterns of activity, in that it was unable to put emotional experiences into context and produce controlled, appropriate responses," said Matthew Walker of the University of California Berkeley, who led the study.      

Walker's team reported back to their findings to the journal Current Biology , he commented on the profound changes in the brain activity of the volunteers who stayed awake for over two days.

"We found a strong overreaction from the emotional centers of the brain," Walker said. "It was almost as if the brain had been rewired, and connected to the fright, flight or fight area in the brain stem."

And lab workers noticed a difference in the behavior of the sleep-deprived volunteers.. "They seemed to swing like a pendulum between the broad spectrum of emotions," Walker said.

"They would go from being remarkably upset at one time to where they found the same thing funny. They were almost giddy - punch drunk."

Following this Walker decided to test people who were chronically sleep-deprived just letting them have 5 hours of sleep over this time several days. On average a person needs 7 to 9 hours sleep a day.

He said the findings may shed light on psychiatric diseases. "This is the first set of experiments that demonstrate that even healthy people's brains mimic certain pathological psychiatric patterns when deprived of sleep."

"Before, it was difficult to separate out the effect of sleep versus the disease itself. Now we're closer to being able to look into whether the person has a psychiatric disease or a sleep disorder."

A second study in the same journal suggests daylight-savings time regimes may cause similar effects.

Till Roenneberg of Ludwig-Maximilian University in Munich, Germany examined the sleep patterns of 55,000 people in Central Europe.

He found people's internal circadian clocks adjusted well when the clock moved back in the autumn months, but failed to adjust when it moved forward, costing them an hour of sleep, in the spring.

He said the effects held for weeks, perhaps causing people to feel continually sleep-deprived in the spring and summer.

David Power