You’ve probably heard the word serotonin thrown around here and there. Often referred to as the happy molecule, serotonin is one of the many chemicals that our brain and body produce to help regulate the many different physical and psychological processes that are underway at any given moment.
If you’ve never actually studied it, though, then chances are that you don’t know much more about the serotonin definition other than the fact that it affects your mood. Serotonin does a lot more than just affect your mood, though. In fact, most of your body’s serotonin spends its entire life hanging out in your digestive tract, not your brain!
Serotonin’s popularity – in so far as a brain chemical can be popular – is largely due to the pharmaceutical industry. The most common antidepressants, which in themselves are the most commonly-prescribed pharmaceuticals worldwide – target serotonin.
These drugs are known as selective serotonin reuptake inhibitors (SSRIs). They basically help your brain make better use of serotonin. Most people don’t research too far beyond what their doctor tells them, so their knowledge about the serotonin definition usually stops here. We’ll talk more about the function of SSRIs later.
For now, though, rest assured that we’ll provide you with all the information about serotonin that you could need in this article. We’ll try not to get too technical. After all, you’re not here to study neuroscience. However, if you are interested in neuroscience, this article might be a good place to start!
What Is Serotonin?
Serotonin is a specific type of chemical called a neurotransmitter. Its chemical name is 5-hydroxytryptophan, often shortened to simply 5-HTP. (That’s right – if you’ve ever seen those 5-HTP supplements in the vitamin aisle, they’re serotonin supplements! However, don’t waste your money on them. We’ll explain why later.)
There are many different types of neurotransmitters in your body, each with its own form and function. These are the compounds that allow your brain and nervous system to communicate.
Each neurotransmitter acts as a sort of ‘key’ for a specific system in the body, unlocking locks that are called receptors. What they do is bind to receptors in the system, either agonizing (activating, or unlocking) or antagonizing (deactivating, or locking) these receptors. Antagonists and agonists can have effects that are the polar opposite of one another, so it’s important to make sure that you know what you’re using!
Serotonin Chemical Effects
If you think serotonin is only involved in regulating our mood, think again. Here are a few examples of some of the most important things that serotonin does.
- Helps to encourage healthy communication among different cells in the nervous system
- Helps to regulate sleep
- Serotonin is important for helping the blood clot to stop yourself from bleeding excessively
- Maintains digestive health and manages hunger
- Manages anxiety levels and other aspects of cognitive/emotional health
- Helps with the development of bones
Because serotonin affects such a wide range of different things, it can be difficult to identify and diagnose an issue related specifically to serotonin. Many people with serotonin-related depression will also struggle with digestive issues, for example.
What Does a Lack of Serotonin Cause?
Since serotonin is responsible for maintaining so many different systems, a serotonin deficiency can be a serious issue. Most people – unfortunately, including most doctors – associate serotonin exclusively with mood.
This means that serotonin drugs are often prescribed in situations where people may very well be producing enough serotonin. On the other hand, serotonin deficiencies can easily go unnoticed because people rarely suspect other serotonin-related issues, such as chronic digestive issues or anxiety, to be related to the ‘happy chemical.’
Because serotonin is involved with so many different things, a deficiency usually results in more than one symptom.
This is also part of the reason that serotonin medication tends to cause such a wide variety of side effects. Many of these side effects result from your body being overburdened with serotonin, which it may not have needed in the first place.
Realistically, doctors should check to ensure that patients meet the criteria of serotonin deficiency – meaning that they present numerous symptoms of low serotonin, not just one (low mood) – before prescribing powerful drugs like SSRIs.
A holistic practitioner would tell you that depression isn’t really reasonable grounds to prescribe to somebody something as serious as a serotonin reuptake inhibitor. Unless you’ve already tried a number of other treatments without much success, SSRIs should be considered fairly serious medicines.
If you’re confident that your problem is the result of a serotonin imbalance, you can always try to take a natural route. St. John’s Wort, for example, has significant SSRI properties and has been proven to be just as effective and in some cases more effective for treating depression, with far fewer side effects.
For example, many people struggle with depression caused by life events. While this can cause a temporary drop in serotonin, the best approach to this would be to unpack the emotions associated with the event with the help of a counselor or therapist.
People may also become depressed because of a lack of exercise or an improper diet.
Taking an SSRI may override this type of depression, but they won’t actually cure it. In other words, you’ll be medicated for a problem that you could heal on your own. One of the reasons tha we go through life is to learn and adapt to different circumstances and challenges. If we just throw drugs at every obstacle that we approach, then we won’t learn much during our journey here.
Here are some of the most common side effects associated with serotonin deficiency.
- Depression. Depression is the ‘granddaddy’ serotonin deficiency syndrome, at least as far as our society is concerned. Serotonin drugs are always the first line of defense against depression in most first-world countries, even though there are countless things that can cause depression, most of which have nothing to do with serotonin. In fact, researchers don’t even fully understand how serotonin deficiency can cause depression, only that there is a complex relationship between the two factors.
- Sleeping disturbances. Serotonin helps to keep the body’s internal clock on time. If you don’t have enough serotonin then your body won’t be able to tell when it’s time to hit the hay and when it’s time to wake up.
- Pain. Serotonin is involved in muscle function. Without it, your muscles may begin to function improperly which could lead to pain that’s difficult to diagnose. Chronic, low serotonin is associated with fibromyalgia, a chronic and painful condition that can affect the whole body.
- Cognitive health issues. Low serotonin levels can interfere with an individual’s cognitive abilities. The deficiency can cause memory problems and make it difficult to learn. In serious cases, people with low serotonin may develop conditions like ADHD.
- Mental and emotional health disorders. Low serotonin levels can contribute to other mental and emotional health issues besides depression. A serotonin deficiency can also cause anxiety and related conditions, such as OCD. In serious cases, it can cause schizophrenia and related behaviors, such as hallucinations and spontaneous mood changes.
- Digestive issues. Since most of your serotonin is located in your gut, it makes sense that serotonin imbalances could cause digestive issues. Low serotonin can interfere with the appetite and can also affect the regularity of your bowel movements and nutrient absorption. IBS and loose stools are common among people with low serotonin.
Serotonin Syndrome (Effects of Too Much Serotonin)
Serotonin syndrome is a potentially permanent condition that can occur when somebody has an excess of serotonin. It most usually occurs when somebody combines medications and/or supplement in dosages that can trigger serotonin syndrome.
Some of the most common symptoms associated with serotonin syndrome are:
- Confusion
- Agitation, restlessness, inability to sit still or relax
- Dilated pupils
- Tremors
- Sweating
- Dry mouth
- Flushed skin
- Twitching or jerking of the muscles
- “Brain zaps,” rapid eye movements associated with an electrifying sensation
- Headaches and migraines
- Changes in blood pressure and temperature
- Digestive issues (nausea, vomiting, diarrhea)
If the serotonin syndrome is serious enough it could result in more dangerous, and potentially fatal, symptoms. These can include a loss of consciousness, inability to respond to external stimuli like voices, comas, or seizures.
If you’re taking a drug or a medication that affects serotonin, like an SSRI, then you should be very careful before taking any other new supplements or drugs. Taking an SSRI in conjunction with another drug that affects serotonin could be enough to trigger serotonin syndrome.
Selective Serotonin Reuptake Inhibitors – SSRI Antidepressants
So, anyway – what do SSRIs do? You can find that out by breaking apart the name: selective serotonin reuptake inhibitors.
The first word, selective, tells us that the medication has a tendency to target a specific system, organ, or tissue – in this case, the serotonin system. Selectivity can vary among different drugs even among different SSRIs.
For example, some drugs are selective not just to a system but also to a specific receptor subtype. For example, most selective serotonin antidepressants target the 5HT2a receptor in the serotonin system, whereas other drugs may be more selective in targeting the 5HT2b receptor (though these drugs are far less common.)
The 5HT2a receptor is the most appealing to doctors and pharmacists interested in helping people balance their moods. It has the strongest influence on our cognitive and emotional health. SSRIs are designed to specifically target this receptor and interfere as minimally as possible with other serotonin subtypes (although, as evidenced by the side effects, this doesn’t work well in practice).
How Does the Body Make Serotonin?
The body has a number of mechanisms that are involved in the production of serotonin. The mechanisms that the body will employ depend on where the serotonin is being manufactured. For example, in the gut, microbes help you produce serotonin. The vast majority of your serotonin is produced in the digestive tract. Even though it is referred to as peripheral serotonin, this is the bulk majority of your body’s storehouse.
Contrary to what researchers previously thought, the microbes themselves don’t actually produce the serotonin – or, at least, not all of it. Instead, they interact with specific types of cells, called enterochromaffin cells, to produce serotonin.
Dopamine vs. Serotonin & Other Neurotransmitters
Even though serotonin is often referred to as “the happy chemical,” there are a lot of other neurotransmitters that are responsible for helping to bring balance to our mood. Of particular interest are dopamine and GABA, responsible for providing us with motivation and drive, and for regulating anxiety, respectively.
Aside from these, there are numerous other neurotransmitters that play different functions in the body and nervous system. We’ll explain a bit about each here.
Dopamine
Dopamine could just as rightfully be called ‘the happy chemical.’ Drugs that affect dopamine levels tend to produce feelings of elated euphoria, motivation, and an intense drive to accomplish things. In fact, dopaminergic drugs tend to produce a more notable mood boost than serotonergic.
Compare, for example, the effects of the highly serotonergic drug MDMA to the effects of a strong dopamine releaser, such as methamphetamine. Methamphetamine initially causes users to experience a powerful spike of dopamine that makes them chatty, euphoric, and potentially manic (mania is a symptom of excess dopamine).
MDMA, on the other hand, produces a different sort of mood boost that’s less in-your-face. It makes users lovey-dovey and fills them with an appreciation for life and the people in it. It is a more blissful experience rather than an intensely motivated one.
GABA
GABA is an inhibitory neurotransmitter. This means that its primary function is to help regulate the function of other neurotransmitters, most especially glutamate. Glutamate is the neurotransmitter responsible for making our nerve cells and brain cells ‘fire,’ so that they can communicate with one another.
However, if we have too much glutamate, or become too sensitive to it, the system becomes overexcited. In our modern, high-stress, busy society, many people are living with overexcited nervous systems. GABA and GABAergic drugs can help to correct this by inhibiting, or slowing, the function of glutamate.
Drugs like Xanax and Valium are benzodiazepines, the most common class of GABAergic drugs. They can be powerfully addictive and should be used with caution.
Glutamate
Glutamate is another important neurotransmitter, although its function is not nearly as relevant for mood as compounds like serotonin or dopamine. Glutamine is our chief excitatory neurotransmitter. It helps to ensure that our nerve cells can communicate with one another.
Without glutamate, we would not be able to think, move our muscles, or perform any number of automatic and manual bodily functions. However, excessive glutamate can cause problems like anxiety or, and serious cases, seizures.
Conclusion
Serotonin. The happy molecule. Even though there are lots of neurotransmitters that are related to our mood, serotonin often takes credit for being the most important one. Whether or not this is true is up for debate, but there’s no doubt that serotonin is important for regulating our physical and mental health across the board.
Antidepressant drugs that target serotonin are the most popular pharmaceuticals on the market. This doesn’t necessarily make them the smartest or safest drugs on the market, but it does help to ensure that the general population is at least aware of serotonin and its importance.
