If you do not get enough sleep your chances of developing a psychiatric disorder are much greater, say researchers from Harvard Medical School and the University of California at Berkeley. Brain scans revealed that the sleep-deprived brain becomes tired and abnormally emotional.

You can read about this latest research in the journal Current Biology, October 23 issue.

The researchers explain that sleep deprivation is known to undermine a range of functions, including immune regulation and metabolic control, as well as learning and memory. However, evidence so far on how sleep regulates our emotional brain-state is very limited.

The scientists had 35 volunteer-participants who did not sleep for 35 hours. They discovered enormous activity in parts of the brain when they looked at pictures aimed at making them sad or angry.

The researchers, with the aid of fMRI (functional magnetic resonance imaging), were able to examine the blood flow in the brains of the volunteers in real time, after and during sleep deprivation. The technology reveals which parts of the brain are experiencing the most activity.

After a long stretch without sleep the participants were asked to look at images that were designed to trigger an emotional response. The scientists explain that the amygdala showed 60% higher reactions to the images compared to people who are not sleep-deprived. The amygdala is a part of the brain which is linked to emotional reactions.

“The size of the increase really surprised us,” commented Matthew Walker. “It is almost as though, without sleep, the brain reverts back to a more primitive pattern of activity, becoming unable to put emotional experiences into context and produce controlled, appropriate responses.” He believes there may well be a link between sleep deprivation/disorders and psychiatric disorders. He added that previous studies had indicated that most patients with psychiatric disorders also suffer from some kind of sleep disorder – it would be interesting, as a result of this study, to look into the mechanisms of why this may be so.

“The human emotional brain without sleep – a prefrontal amygdala disconnect”
Seung-Schik Yoo, Ninad Gujar, Peter Hu, Ferenc A. Jolesz, and Matthew P. Walker
Current Biology, Vol 17, R877-R878, 23 October 2007
Click here to view abstract online

Written by: Christian Nordqvist