What Is The Difference Between Serotonin And Dopamine?
By Sarah Fader
Updated May 09, 2019
Reviewer Jeffrey Craven , MA, LMHC, LPCC, LLC
The brain is the most complex organ in the body. Composed of the body's control center are over 100 billion nerves that are constantly communicating with one another, controlling what we do, think, and feel.
When the brain and all of its parts are functioning optimally, all is well. However, sometimes one piece of the puzzle falls out of place, creating problems for mental or physical health. Many people struggling with their mental health are dealing with imbalances of the neurotransmitters serotonin and dopamine. Everyone has felt the impact of these brain chemicals, whether positive or negative, but most people do not know what they are or what they do.
While serotonin and dopamine are both neurotransmitters and are both considered "happy chemicals," they have different, distinct functions. It is also important to note that serotonin and dopamine are not only related to mood and happiness. They also play a role in things like sleep, digestion, pain response, and other bodily functions.
Serotonin Vs. Dopamine
What Is Serotonin?
As a neurotransmitter, serotonin is responsible for sending signals between cells of the body. While its most well-known functions have to do with brain function and mood, most of the serotonin in your body is found in the digestive system. This is because serotonin is produced from the amino acid tryptophan. Tryptophan is an essential amino acid, which means the body cannot produce it on its own and you must consume the amino acid via your diet. You may have heard of tryptophan before around Thanksgiving time- it is the chemical found in turkey that is said to make people feel blissful and sleepy after their big Thanksgiving meal. But, turkey is not the only source of tryptophan. Eggs, tofu, salmon, and nuts are all great foods to eat to make sure you are meeting your tryptophan needs and supplying your body with plenty of material to work with to create serotonin.
As most people know, serotonin is often associated with happiness and good moods. But rather than thinking of serotonin as a mood booster, think of it as a mood regulator. Serotonin keeps moods stable and should prevent any major fluctuations in happiness, which is why serotonin deficiency is often associated with depression. But, serotonin does much more than regulate mood. Some of its other functions include:
- Sleep: Serotonin plays a big role in our sleep/wake cycles. Unlike the hormone melatonin, which helps you fall asleep at night, serotonin helps promote wakefulness in the morning.
- Digestion: As previously mentioned, most of the serotonin in your body is found in your stomach and intestines, not your brain (though it sends signals to the brain and impacts its function). It helps regulate bowel movements and other digestive functions.
- Wound Healing: In addition to the stomach, serotonin is found in blood platelets. When you are injured, your body releases serotonin out of the blood platelets to facilitate blood clotting.
What Is Dopamine?
Like serotonin, dopamine is an important neurotransmitter. It is connected with the brain's "pleasure center," and can drive our behavior towards things that bring a spike to that center of the brain. But, like serotonin, dopamine has many functions beyond pleasure and happiness. It also plays a critical role in the movement, including Parkinson's disease and its characteristic tremors. The dopamine that is responsible for controlling movement and related to Parkinson's disease is found in the substantia nigra area of the brain.
Still, most people are interested in dopamine for its role in the brain's pleasure and reward center. Dopamine is often discussed in association with drug addiction because it can drive behavior towards things that will activate the pleasure centers of the brain. Specifically, dopamine created in the ventral tegmental area (VTA) of the brain is associated with rewards. Dopamine is released from the VTA into the rest of the brain when a person does something and receives, or even just expects, a "reward," or pleasure. This spike of dopamine then motivates the person to continue performing this behavior that brought them the reward. Dopamine helps drive humans towards necessary behaviors, like drinking water and eating food, but can also bring people to act on less healthy behaviors, like binge eating or drug use.
The Differences Between Serotonin And Dopamine
As you can see, serotonin and dopamine serve different purposes in the brain. They are both neurotransmitters and function as messengers between brain cells. They also both have positive associations, as serotonin stabilizes mood and dopamine signals rewards. But, their core functions are quite different. Dopamine brings feelings of pleasure and provides a happiness boost based on a certain action, while serotonin is more of a stabilizer than a booster. The non-mood related functions of serotonin and dopamine also differ, as dopamine primarily controls movement and serotonin contributes to sleep and digestion.
Other Important Neurochemicals
There are a few other neurochemicals that often come up when discussing serotonin and dopamine. Oxytocin and endorphins are the other "feel good" chemicals that play a role in your daily life and mood.
Oxytocin: Oxytocin is both a hormone and a neurotransmitter. In popular culture, it is often referred to as the "love hormone," for its ability to bring about feelings of intimacy. It is released during orgasm for both men and women and is associated with fidelity in relationships. Another name for oxytocin is the "cuddle hormone," because simply hugging someone is a great way to get a boost of the neurotransmitter. And, it is not only important for romance. Oxytocin can help facilitate strong social bonds in many settings, including with friends and coworkers.
Endorphins: Endorphins are another member of the "feel good" chemical family. Unlike serotonin and dopamine, endorphins are not neurotransmitters, but rather a neurochemical that binds to receptors in the brain. Most people associate endorphins with exercise or the "runner's high" one feel upon completing their workout. Endorphins are similar to morphine, as they reduce one's perception of pain and work as a sedative. If you are not someone who enjoys working out, you can still get an endorphin boost by simply having a good laugh. Laughter, or even the anticipating of laughter, is known to send a spike of endorphins to the brain.
Serotonin, Dopamine, And Mental Health
Given the many important functions of serotonin and dopamine, it is no surprise that they play a major role in mental health. When both of the neurotransmitters are functioning as they should, they help someone feel balanced and happy. However, problems can arise when serotonin and dopamine levels are imbalanced.
When serotonin levels are balanced, you should feel calm, happier, and more focused. But, imbalances are associated with a range of mental health problems, most notably depression.
It is well known that there is a relationship between serotonin and depression. However, there is a lack of consensus about how they are related. While the common theory remains that low levels of serotonin are what causes depression, there are now some that believe the opposite- that depression causes serotonin levels to drop. Still, what everyone can agree on is that serotonin and depression are related. If you are struggling with depression, it is always a good idea to talk to a therapist.
In addition to depression, low levels of serotonin have also been associated with insomnia and anxiety. Adequate serotonin levels are very important for getting a good night's sleep, and many natural sleeping supplements contain serotonin precursors to help facilitate this process.
The most widely used serotonin medications are selective serotonin reuptake inhibitors or SSRIs. SSRIs such as Prozac, Lexapro, and Zoloft are commonly prescribed as antidepressants. SSRIs work by blocking the reuptake of serotonin into the brain so that more of it is available for use. This is an effective treatment because many people with depression have lower than normal levels of serotonin in the brain. Making more serotonin available can help ease some of the symptoms of depression. In addition to depression, some SSRIs are used to treat anxiety or even insomnia (such as Trazodone).
The different SSRIs have somewhat different chemical makeups, so if you have negative side effects from one, you may be able to take another. A psychiatrist can help you find the best medication and dosage combination for your body.
Dopamine impacts one's movement and behavior. The most well-known aspect of dopamine is its role in drug addiction. As previously discussed, dopamine works with the brain's reward system to motivate people to act in ways that will bring them a dopamine boost. Of course, one way to get a strong hit of dopamine is drug use. Drugs like alcohol and cocaine, as well as less intense substances that some people use daily, such as caffeine and nicotine, are all related to dopamine release.
These drugs increase the amount of dopamine in the brain, so the person feels compelled to keep using to feel the same reward for the behavior. Drug tolerance occurs when the brain gets used to this increased level of dopamine, so the person has to use more and more of the drug to feel the same boost in dopamine as they did when they started using.
Dopamine deficiency is associated with Parkinson's disease, as dopamine plays an important role in controlling movement.
Dopamine medications fall into one of two categories: agonists or antagonists. Dopamine agonists activate dopamine receptors to increase the amount of dopamine in the brain. They are useful to treat conditions related to dopamine deficiency, specifically Parkinson's disease. They are also used to treat restless leg syndrome (RLS), as the mechanism behind this condition is similar to what causes tremors in people with Parkinson's. Indirect agonists can be used to treat attention deficit disorders.
On the other hand, dopamine antagonists block dopamine receptors, similar to how an SSRI functions. Most of these drugs are used as antipsychotics to treat conditions such as schizophrenia or bipolar disorder.
Serotonin and dopamine are just two of the many moving parts that make up the brain. Understanding these two neurotransmitters, and how they impact your mood and behaviors on a daily basis, can help bring you one step closer to comprehending the complex system that is the human body.