Lack of sleep is common in anxiety disorders, but it may play a key role in revving up brain regions that contribute to excessive worrying, UC Berkeley researchers have found.
Being deprived of sleep, neuroscientists have found, boosts anticipatory anxiety by sparking the brain’s amygdala and insular cortex, areas linked to emotional processing. The ensuing patterns imitate the abnormal neural activity seen in anxiety disorders.
In addition, this research suggests that innate worriers, people who are naturally more anxious and so more likely to develop a full-blown anxiety disorder, are acutely vulnerable to the impact of not enough sleep.
“These findings help us realize that those people who are anxious by nature are the same people who will suffer the greatest harm from sleep deprivation,” said senior author Matthew Walker, a professor of psychology and neuroscience.
Sleep Restoration Possible Anxiety Treatment
“If sleep disruption is a key factor in anxiety disorders, as this study suggests, then it’s a potentially treatable target,” Walker said. “By restoring good quality sleep in people suffering from anxiety, we may be able to help ameliorate their excessive worry and disabling fearful expectations.”
Although existing research indicates that sleep disruption and psychiatric disorders regularly occur together, this latest study is the first to demonstrate causally that sleep loss triggers excessive anticipatory brain activity associated with anxiety.
“It’s been hard to tease out whether sleep loss is simply a byproduct of anxiety, or whether sleep disruption causes anxiety,” said doctoral student Andrea Goldstein, lead author of the study. “This study helps us understand that causal relationship more clearly.”
Neutral, Disturbing and Random Images
The experiments, performed at UC Berkeley’s Sleep and Neuroimaging Laboratory, involved researchers scanning the brains of 18 young adults as they looked at dozens of images, first after a good night’s rest, and again after a sleepless night. The images were either all neutral, disturbing or alternated between both.
Participants reported a broad range of baseline anxiety levels, with none fitting the criteria for clinical anxiety disorder. After a full night’s rest at the lab, monitored by researchers measuring neural electrical activity, their brains were scanned via functional MRI as they waited to be shown, and then viewed 90 images during a 45-minute session.
To set off anticipatory anxiety, researchers primed the participants using one of three visual cues prior to each series of images. A big red minus sign signaled to participants that they were about to see a very unpleasant image, like a death scene.
A yellow circle signaled the neutral image, such as a basket on a table. Possibly most stressful was a white question mark, indicating that either a grisly image or a bland, innocuous one was coming, and kept participants in a heightened state of suspense.
In the case of being sleep-deprived plus waiting in suspenseful anticipation for a neutral or disturbing image to appear, the activity in the emotional brain centers of all the participants skyrocketed, particularly in the amygdala and the insular cortex.
Remarkably, the amplifying impact of sleep deprivation was most dramatic for those people who were innately anxious to begin with.
“This discovery illustrates how important sleep is to our mental health,” said Walker. “It also emphasizes the intimate relationship between sleep and psychiatric disorders, both from a cause and a treatment perspective.”
A. N. Goldstein, S. M. Greer, J. M. Saletin, A. G. Harvey, J. B. Nitschke, M. P. Walker.
Tired and Apprehensive: Anxiety Amplifies the Impact of Sleep Loss on Aversive Brain Anticipation
Journal of Neuroscience, 2013; 33 (26): 10607 DOI: 10.1523/JNEUROSCI.5578-12.2013