A sleepless night could reverse the effects of depression according to a recent study

in collaboration with

Amélie Boukhobza (Clinical psychologist)

We know the effects of chronic sleep loss and its many harmful effects on health, but brief sleep loss (such as a sleepless night before an exam, for example) is less well understood. To find out more, scientists who are experts in brain neuroplasticity have conducted various experiments with surprising results.

Antidepressant effects for several days

Most people who have had a sleepless night know this feeling of “tiredness and tension” all too well. Although the body is physically exhausted, the brain feels cheerful and almost dizzy.

In this new study, researchers induced mild, acute sleep deprivation (avoiding inducing stress) in mice, then examined their behaviors and brain activity. After a sleepless night, the animals’ behavior changed to become more aggressive, hyperactive and hypersexual, compared to controls who experienced a typical night’s sleep.

The activity of dopamine neurons, responsible for the brain’s reward response, was higher in the animals during the brief period of sleep loss. Not only was dopamine release increased during the period of acute sleep loss, but synaptic plasticity was also enhanced, literally rewiring the brain to maintain a bubbly mood for the following days.

While most behaviors (such as hyperactivity and increased sexuality) disappeared within hours of acute sleep loss, the antidepressant effect persisted for a few days.

The multiple roles of dopaminergic neurons

The researchers found that three brain regions responsible for dopamine release (the prefrontal cortex, the nucleus accumbens, and the hypothalamus) were involved. By “turning off” the dopaminergic reactions in these areas one by one, the researchers discovered that the antidepressant effect was linked to the medial prefrontal cortex. On the other hand, the nucleus accumbens and the hypothalamus seemed to be the most involved in hyperactive behaviors.

“The antidepressant effect persisted except when we silenced dopamine inputs to the prefrontal cortex“, Kozorovitskiy said. “This means that the prefrontal cortex is a clinically relevant area when searching for therapeutic targets. But it also reinforces the idea that has been developing recently: dopamine neurons play very important but very different roles in the brain. It’s not just this monolithic population that just predicts rewards.”.

An effect inherited from evolution?

Although researchers don’t really understand why sleep loss causes this effect on the brain, Kozorovitskiy suspects that evolution is at play.You can imagine certain situations where there is a predator or some sort of danger where you need a combination of relatively high functions and an ability to delay sleep (…) I think that might be something that we let’s see here. If you regularly lose sleep, various chronic effects will set in and be uniformly detrimental. But transiently, you can imagine situations in which it is beneficial to be intensely alert for a period of time“.

However, P Kozorovitskiy also warns people not to start having sleepless nights in order to fight against discomfort or dark feelings. “The antidepressant effect is temporary and we know the importance of a good night’s sleep. I would say it’s better to go to the gym or take a nice walk. This new knowledge is more important when it comes to matching someone with the right antidepressant“.

A feeling shared by our expert Amélie Boukhobza, clinical psychologist, who is enthusiastic about the results of this study while recalling the benefits of a good night’s sleep.