Serotonin Vs. Dopamine: Understanding The Similarities & Differences

Serotonin and dopamine belong to a group of neurochemicals, or chemical messengers in the brain, known as neurotransmitters. High or low serotonin or dopamine levels in a person's brain can affect a person's mood (or depression levels) in addition to other essential functions. Here, you will learn about the difference between these two, how these neurotransmitters influence how we feel, and how they are involved in the treatment of various mental conditions.

What Is A Neurotransmitter?

As mentioned in the introduction, neurotransmitters are chemical messengers in the brain that send signals to other parts of the body. All neurotransmitters have various functions in the body. However, serotonin, dopamine, and norepinephrine all belong to a specific group of neurotransmitters called monoamines. Deficiency in these monoamines is connected to several common mental disorders. Fortunately, with professional help, monoamine levels can be improved.

The Importance of Neurotransmitters: Focus On Serotonin and Dopamine 

However, sometimes, one component falls out of place or stops communicating with the control center, creating problems for mental or physical health. People struggling with mental health issues are often dealing with imbalances of serotonin and dopamine. Everyone experiences 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," as they affect mood, 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 important bodily functions, such as sleep, digestion, and pain response.

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, the chemical found in turkey that is said to make people feel blissful and sleepy after their Thanksgiving meal. However, 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 regulator instead. Serotonin keeps feelings stable and should prevent any major fluctuations in happiness, which is why serotonin deficiency is often associated with depression. Serotonin does much more than regulate mood, though. 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 toward things that bring a spike to that center of the brain. However, like serotonin, dopamine has many functions beyond pleasure and happiness. It also plays a critical role in the movement, including for individuals living with Parkinson's disease and its characteristic tremors. The dopamine that is responsible for controlling motor patterns and related to Parkinson's disease is found in the substantia nigra area of the brain.

Still, most interest in dopamine springs from its role in the brain's pleasure and reward center. Dopamine is often discussed in association with drug addiction because it can drive behavior toward 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 toward necessary actions, like drinking water and eating food, but can also influence people to act on less healthy behaviors, like binge eating or drug use.

Serotonin Vs Dopamine

Serotonin and dopamine are both neurotransmitters and function as messengers between brain cells. They also both have positive associations, as serotonin stabilizes mood and dopamine signals rewards. Despite these similarities, though, 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 impacts 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 our daily lives and moods.

• 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 by all genders 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. Oxytocin is not limited to romantic situations; it can help facilitate strong social bonds in many settings, including with friends and coworkers.
• 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 reduce perceptions of pain and also work as a sedative. If you do not enjoy working out, you can still get an endorphin boost by simply having a good laugh. Laughter, even the anticipation of laughter, is known to send a spike of endorphins to the brain.

Serotonin, Dopamine, And Health: What Do Low Or Imbalanced Levels Mean?

Given the many important functions of serotonin and dopamine, it is no surprise that they play major roles 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.

Serotonin-Related Conditions

When serotonin levels are balanced, you should feel calmer, happier, and more focused. Imbalances are associated with a range of mental health disorders, most notably depression.

It is well known that there is a relationship between serotonin and depression. However, there is a lack of consensus about exactly how they are related. Conventional wisdom has stated that low levels of serotonin may cause depression, but others now believe that depression causes serotonin levels to drop. Overall, it is commonly agreed that serotonin levels and depression are related. Additionally, women synthesize serotonin much more slowly than men, which can increase lifelong odds of developing depression. 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 are associated with insomnia and anxiety. Adequate serotonin levels are important for getting a good night's sleep, and many natural sleeping supplements contain serotonin precursors to help facilitate this process.

Serotonin Medications

The most widely used serotonin medications are selective serotonin reuptake inhibitors or SSRIs, such as Prozac, Lexapro, and Zoloft, which 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 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).

Various SSRIs have different chemical makeups, so if you experience 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-Related Conditions

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, all impact dopamine release.

These substances increase the amount of dopamine in the brain, so the person feels compelled to keep using to feel the same reward for the behavior. Substance tolerance occurs when the brain gets used to this increased level of dopamine, so the person has to use more and more of the substance to feel the same boost in dopamine as they did when they started using.

Dopamine Medications

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.

By contrast, dopamine antagonists block dopamine receptors, similar to the functioning of an SSRI. These drugs are often 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 daily, can help bring you one step closer to comprehending the complex system that is the human body.

Seeking Therapy For Dopamine and Serotonin Imbalances

While the previous sections discuss how serotonin and dopamine levels can be adjusted through medication, therapy is a viable solution as well.