Staying up all night can actually ease depression in some people

As most new parents can attest, sleepless nights aren’t exactly the happiest mornings. This is why it doesn’t make much sense that total sleep deprivation temporarily resets the mood of nearly half of people with major depressive disorder.

Brain scans on volunteers have shown why this might be the case, revealing intriguing changes between critical brain areas in healthy volunteers and those diagnosed with major depression.

Research conducted by the University of Pennsylvania in the United States used functional magnetic resonance imaging to map and measure the brain functions of 54 individuals without a history of psychiatric or mood disorders and 30 with major depression.

Of those without a history of depression, 16 were placed in a control group and received a good night’s sleep between tests. For everyone else, diagnosed and undiagnosed, it was a long evening of reading, computer games, television, and no shuts. No caffeine, no exercise. Only boredom until dawn.

Lacking sufficient time to rest and replenish, the human brain isn’t the most efficient machine. A piece of tissue in the front of our brains called the dorsolateral prefrontal cortex moves slowly, making it harder to pay attention.

Not only is our cognition slowed, but so is our ability to regulate our emotions as the amygdala, a key component of the limbic system, works overtime, especially in response to negative stimuli. Without the prefrontal cortex to temper our thinking, we can become snappy and irritable.

However, since the dawn of psychiatric research, sleep deprivation has been seen as a potential treatment for relieving depression, at least in a percentage of individuals who experience it as a persistent state of mind.

Sure enough, the researchers behind this latest survey noticed an improvement in mood in 13 of 30 patients with major depression after the sleepless night.

Meanwhile, the results of a mood test on those who weren’t depressed generally reflected the kind of tired jitters most experience when sleep deprived.

The imaging data revealed a possible explanation behind this contrast. Connections between the amygdala and a bridge between cognitive and emotional regions of the brain called the anterior cingulate cortex appeared to be enhanced in those whose moods would improve, regardless of their mental health.

Even after two nights of catching up on lost sleep, this connectivity between the two regions remained relatively strong.

Known as chronotherapy, the principle of treating psychiatric conditions through changes in biological rhythms has become a serious field of study, suggesting that a jolt to our biological clock could somehow reset regulatory processes that have gone awry.

That’s not to say frequent sleepless nights are necessarily a good idea for anyone, with sleep disturbances linked to higher risks of dementia later in life. Playing with the biological clock can take a toll on our health, our social life and our working day.

However, mapping the dramatic changes in communication between brain areas known to be involved in emotional and cognitive regulation following a sleep loss could help establish the possible mechanisms responsible for at least some cases of depression.

The World Health Organization classifies major depressive disorder as the third largest disease burden worldwide. Knowing that it’s at least possible to improve connectivity between areas of the brain critical to mood, we may one day find a way to lift the mood of millions without robbing our brains of the benefits of a good night’s rest.

This research was published in PNAS.