Sleepless nights can leave brains feeling anxious

SAN DIEGO, Calif. — Missing a single night of sleep can leave the brain anxious the next day. That’s the finding of a new study from the University of California, Berkeley.

Sleep researchers Eti Ben Simon and Matthew Walker invited healthy adults to sleep overnight in their lab. Whether someone slept or not affected their anxiety in the morning. A wakeful night also changed patterns of brain activity.

The scientists reported these results November 4 at the annual meeting of the Society for Neuroscience, in San Diego, Calif.

People with anxiety disorders often have trouble sleeping. The new results show the reverse may be true, too: Poor sleep can lead to anxiety.

“This is a two-way interaction,” says Clifford Saper. He works at Harvard Medical School and Beth Israel Deaconess Medical Center in Boston, Mass. He studies sleep but wasn’t part of the new study. “Sleep loss makes the anxiety worse,” he notes, “which in turn makes it harder to sleep.”

The new study enrolled 18 healthy volunteers. They either got a full night of sleep or stayed up all night. The next morning, each person took a test to gauge signs of anxiety. They also laid in a brain scanner and watched short videos. These were designed to spark emotional reactions. The scanner recorded patterns of brain activity as the volunteers watched.

On a different night, the volunteers switched groups. Those who slept the first time now had to stay up all night. The previously sleep-deprived people got some shut-eye. The next morning, each repeated the anxiety test and brain scan.

Sleep makes a big difference, those tests showed. Staying awake all night boosted anxiety levels 30 percent above those that were typical after getting a night’s sleep. Just one sleepless night boosted anxiety in healthy recruits to levels seen in people with anxiety disorders. Ben Simon described that finding November 5 to news reporters at the conference.

What’s more, brain activity in sleep-deprived people was different. Parts of their brains involved in emotions were more active than usual when they watched emotional videos. And an area that can put the brakes on anxiety, known as the prefrontal cortex, was less active than normal.

The results suggest that poor sleep “is more than just a symptom” of anxiety, Ben Simon says. In some cases, it may help cause the condition.