One night without sleep has an antidepressant effect
A study conducted by the Perelman School of Medicine at the University of Pennsylvania in Philadelphia examined the somewhat controversial phenomenon of sleep deprivation leading to improved mood in patients with depressive disorders.The research team mapped the activity of brain regions using functional magnetic resonance imaging at rest to understand why sleep loss has a positive effect in some people.
The study found that one night of total sleep deprivation improved amygdala connectivity to the anterior cingulate cortex, which correlated with better mood in some healthy and depressed people.
In sleep deprivation experiments performed on both healthy subjects (n=38) and patients with major depressive disorder (n=30), as well as on 16 control groups who were allowed continuous sleep, researchers examined the effects of total sleep deprivation (TSD) on mood and functional communication networks.
The experiments were conducted in the laboratory of the Center for Clinical Translational Research at the University of Pennsylvania Hospital for five consecutive days. All participants received three sessions of fMRI scans. A total of 210 fMRI images were obtained for each participant.
Participants underwent three resting-state fMRI scans over a five-day period. The first scan was performed after normal nocturnal sleep on the morning of the second day as baseline. In the TSD groups, participants had a second scan session on the morning of the third day after no sleep.
Participants were then given two nights of restful sleep and a final scan session on the morning of day five. All participants completed an abbreviated version of the 37-item Mood State Profile every two hours on days two through five.
As expected, the majority of participants had a worsening of mood immediately after their lack of a night's sleep. Thirteen of 30 (43%) participants with depression experienced mood improvement, and the remaining 17 participants experienced mood deterioration or no change after one night of TSD.
After one night of restful sleep, 20 participants with major depressive disorder had improved mood, while the remaining participants had worsened or no change in mood.
The connection between the amygdala and anterior cingulate cortex increased significantly in patients with improved mood, but decreased in patients with unimproved mood. The amygdala is the nucleus of the "hit or run" response, processing frightening or threatening stimuli and signaling other parts of the brain to respond.
The article "Improved connectivity between the amygdala and cingulate gyrus is associated with better mood in both healthy and depressed people after sleep deprivation" is published in PNAS.