If you have been a regular sleeper and just recently felt the “perks” of sleep-deprived lifestyle, you might be surprised to experience a sudden rush of adrenalin or a state of euphoria after a night of poor sleep. Usually, symptoms such as fatigue and sleepiness are expected as outcomes of sleep deprivation, but lesser known side effect gives us quite the opposite feel. Euphoria can be described as a feeling of happiness, excitement, wellbeing, and many daily activities can trigger this condition, but also some neurological disorders and drugs have been recognized as stimulants or causes of euphoria.   

The first all-nighter after a while usually provides that extra buzz on the day after, research show that we owe that to the increased level of dopamine. That can potentially be the way in which our brain is trying to fight off sleepiness and function as normal as possible on the day after a sleepless night. But, the brain’s defense mechanism only masks the real problem for a certain amount of time; once the effects of dopamine increase vanish, the fatigue will strike down on us hard.

This sudden mood boost has even been considered as a short-term treatment for depression. There have been some indications that the symptoms of depression can decline for around 40% to 60% after a whole night of wakefulness. However, that is not a recommended way of treatment in any case, since sleep deprivation can cause more severe problems while ostensibly solving one.


One Sleepless Night

You do not have to be chronically sleep deprived to experience consequences of poor sleep, and sometimes it is hard to pay off just one night of sleep debt. Sleeping is important for many reasons, while we are resting, our body is working and performing multiple restorative processes which all help us to function on the next day. Since we are a sleep-deprived nation, many of us are already used to the fact that we sometimes need to sacrifice a night or two in order to do something on time or just to binge-watch a tv show. However, the reason why we continue to do that even though we know that losing sleep is not good for us is that we know that we can make it, we know that somehow we can survive and stay awake on the day after a sleepless night.

Some days are harder than the others, but yet there are those days when we stay up all night, and with the first rays of sun we feel good, no fatigue, no yawning, nothing, we just go out and do whatever we need to do that day. And no, that is not a sign that you have become resistant to sleep deprivation, or that you are so used to it that it has become normal. Feeling good, motivated and powered even though you did not shut your eyes for even five minutes is also a side effect of sleep deprivation.

Researchers from Berkeley and Harvard Medical School examined the brains of young adults and found out that their brains got a boost of pleasure after a sleepless night. When our brain functions normally it finds a sweet spot on the mood spectrum, but a brain of a sleep-deprived person will switch to one of two extremes, and neither one of them is considered good for decision making. This study also pointed out that professions such as doctors or pilots, people who take important and risky decisions on a daily basis, are especially at risk of making bad choices with fatal consequences if they are sleep deprived.

Intrigued by the fact that many patients with diagnosed clinical depression feel better and positive after a sleepless night, researchers used MRI to see what is going on inside of the brains of people who pulled an all-nighter, compared to those who were sleeping the last night. A total of 27 young adults aged from 18 to 30 years participated in this research, various images were shown to them, and their task was to rate them as positive or neutral. The group of all-nighters gave more positive feedback on the pictures, while the ones who were well rested gave a more moderate score. That shows that the participants who were awake for the past 30 hours have an overall more positive attitude towards basically everything, but that was impacting their judgmental abilities and hindering their objective point of view.

Brain scans of all-nighters showed that there is a higher activity in their mesolimbic pathway which is a brain circuit driven by dopamine, and dopamine regulates our positive feelings, motivation, cravings, addiction, etc.

After a night of good sleep, our frontal lobe regions are highly connected to the dopamine reward regions, but when we stay up all night, a disconnection occurs between the prefrontal cortex and mesolimbic pathway. This leans on the previous conclusions and researches of this team, which have also shown that sleep deprivation shuts down those regions in our brain which are in charge of decision making and planning while activating some more primal neural functions in the amygdala region.

Another study from 2012. also tried to inspect what is happening in our brain after a wholly sleepless night. Since dopamine has two main types of receptors, they hypothesize that the D2 receptor controls wakefulness. So, their question was, what is causing the decrease of D2 receptors when people are sleep deprived? Their first guess was that the increased release of dopamine was responsible for that because when some receptors are overstimulated, they leave the membrane. A group of volunteers was kept awake the whole night, while the other group was sleeping tight, so the next morning they checked the D2 receptors in the striatum, area full of dopamine. They realized that D2 receptor binding was much lower in the brains of sleep-deprived people, so does that mean that tiredness causes increased release of dopamine, which as a consequence has a decrease in D2 receptors? Or do the receptors decrease for some other reason? Most probably it will still remain a mystery, the researchers tried to test their theory one more time and treated their participants with methylphenidate which increases dopamine to see will it gave them higher dopamine release in well-rested participants than sleep deprivation. But, there was no significant difference, which means that the decrease of D2 receptors is not caused by the higher release of dopamine due to sleep deprivation. Their second guess was that adenosine, which is a neurochemical that promotes sleepiness. Caffeine increases wakefulness by counteracting the adenosine receptors, and one of the areas included in these effects is striatum, which is very high in dopamine. So their next mission is to see how adenosine and dopamine interact in the brains of sleep-deprived people.

Changes in receptors can also be linked to some risky behavior and impulsiveness which usually follows sleep deprivation. Although those changes in D2 type of receptors are visible, there is still no scientific explanation that can tell us why do they happen.


What is Dopamine?

Dopamine is usually widely associated with some positive conditions such as bliss, euphoria or motivation, but is it a thrill pill, happy hormone or something else?

Just like, for example, serotonin, dopamine is one of the hundreds of different brain chemicals called neurotransmitters, released by the brain cells. Dopamine is created by neurons when an enzyme called tyrosine hydroxylase gets combined with tyrosine, which is an amino acid. Neurotransmitters are in charge of controlling many body functions and transferring signals from the brain through the body. Although dopamine has been found in many animals, humans have three times more dopamine-producing neurons than most of the primates.

Dopamine has a key role in many body functions, such as sleeping, learning, movement, mood, attention, memory, etc. It is essential to know that dopamine will affect you positively only when its level is optimal, inadequate level or dopamine deficiency can even cause some negative outcomes, and one of them is depression. On the other hand, an increased level of dopamine makes us act and feel like we are on drugs since people experience something similar to losing their touch with reality.


Dopamine Effects

Researcher James Olds performed some of the earliest experiments inspecting dopamine back in the 1950s and 1960s. He experimented with rats, and find out that when their brains receive electrical stimulation at a certain area, they will keep performing some action over and over. At first, scientists suspected that dopamine somehow causes pleasure, and since people who suffer from depression usually had a lower level of dopamine in their brains, it supported their assumption that less dopamine means less pleasure. But, research from the 1980s proved that theory wrong. It was another experiment on animals, this time, their dopamine cells were dashed by drugs, but the animals still enjoyed the taste of sugar, according to their faces. They came to the conclusion that dopamine is not responsible for causing pleasure, but it does impact the way how pleasure affects our brain.

When we experience some pleasure, such as eating our favorite cake, our brain releases more dopamine, which will make you feel good about it, and that is why dopamine is often connected to addiction. Dopamine is the reason why we feel that urge to satisfy our cravings. And, we all want to feel good all the time, who does not, but some people seek illegal substances that increase their level of dopamine in an unhealthy way. Many recreational drugs stimulate the release of dopamine in our brain, causing addiction because the dopamine produced as a result of drug usage has a more long-lasting and intense effect than a piece of cake or anything else. When you finish your piece of cake, that intense feeling of pleasure will quickly start to fade, but with drugs it does not stop once you are done with your act, it gets you high and out of control. Now here is the part when it all goes down for drug addicts since constant use of drugs makes changes in their brains. Due to the over the top dopamine production, the brain starts to shut down some of the dopamine receptors, but the brain is still used to expect that pleasure caused by drugs, so in order to achieve the same amount of pleasure, addicts use more and more drugs. But the process of shutting down the receptors slowly takes that feeling away from them, causing the condition called anhedonia, which is a state when nothing feels right. Low level of dopamine receptors is responsible for impulsive and risky behavior, but that is not only connected to drug addicts, many gamblers or extreme sports aficionados are also risk takers due to their naturally smaller number of dopamine receptors. People who have a fewer amount of these receptors also have a problem with the regulation of released dopamine.


Can Sleep Deprivation Cure Depression?

This is a somewhat bizarre treatment for depression which was tested and proven decades ago. It has been shown that sleep deprivation rapidly alleviates symptoms of depression in up to 50% of depressed people, but there is still no reasonable explanation why it works for some people and for the others does not. Around 200 years ago, a German psychiatrist, Johann Christian August Heinroth, was testing sleep deprivation as a treatment for a condition then called melancholia. Since this phenomena became a huge field of interest for many psychologists, this treatment or process was established as a so-called Wake therapy, and it quickly became as popular as treatments with antidepressant drugs.

The main disadvantage is that symptoms of depression recur quickly, even after a day, since its effects are not long lasting. Regardless of that, researchers of this treatment for depression have come up with some new data, a study from 2015. found out that sleep deprivation impacts the same receptor for mood regulation as the ketamine and tricyclic antidepressants.

People who suffer from depression should never start this therapy randomly or on their own since sleep deprivation will never be a viable therapy for clinical depression. A sleepless night will provide that short-term experience of euphoria, but for those people who are suffering from depression, once the feeling of pleasure starts to fade, their coming back to reality would be even harder. Hopefully, ongoing research will give us more information on how sleep deprivation affects depression, and create a drug that can replicate its effects, without losing precious sleep time.



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