Serotonin vs Dopamine and Their Roles in Depression
Explore the intricate interplay between serotonin and dopamine and their distinct roles in the complex landscape of depression.
Correcting deficiencies or dysfunction of the neurotransmitters serotonin and dopamine is the key to treating depression. Learn how to do this naturally.
There are over one hundred known neurotransmitters, but two of them — serotonin and dopamine — get the most attention by far.
Serotonin and dopamine are similar in structure and both are considered “feel-good” brain chemicals.
While they each have their own unique set of functions, both play an important role in one of the most prevalent mental disorders — depression.
For decades, the prevailing theory has been that depression is caused by a lack of serotonin.
But now, there’s compelling evidence that dopamine is equally important for a positive mood and good mental health.
Serotonin vs Dopamine: How Each Influences Mental Health
Before we examine how serotonin and dopamine contribute to depression, here’s a brief summary of their most important functions and symptoms of dysfunction.
Serotonin: The “Happiness Molecule”
Serotonin helps regulate mood, sleep, memory, appetite, and social behavior.
It is popularly known as the “happiness molecule” for its importance to a positive mood.
A key symptom of poor serotonin activity is a lack of enthusiasm for things you once enjoyed, such as favorite foods, hobbies, and relationships.
Other symptoms are insomnia, excessive eating, and anger.
Disorders linked to a low serotonin level include:
- depression
- anxiety
- eating disorders
- obsessive-compulsive disorder
The current first-line treatment for depression is prescription medications that increase the serotonin level in the brain.
Higher than normal levels of serotonin are linked to social anxiety and autism spectrum disorder.
Dopamine: The “Motivation Molecule”
Dopamine is our “motivation molecule.”
It helps give us the drive we need to take action.
Dopamine is also in charge of the pleasure-reward system.
“ People with dopamine-related depression often self-medicate with substances and activities that flood the brain with dopamine, such as excessive coffee, sugar, cigarettes, shopping, gambling, porn, and recreational drug use.
The release of dopamine is triggered when your needs are about to be met.
The main symptoms of a low dopamine level are lack of motivation, hopelessness, and general apathy.
Too much dopamine can make you overly competitive, impulsive, aggressive, and prone to addictions of all kinds.
Disorders linked to dopamine dysfunction include:
- attention disorders
- bipolar disorder
- depression
- obsessive-compulsive disorder
- Parkinson’s disease
- schizophrenia
The medical establishment typically looks at dopamine as a factor in depression only after serotonin-based treatments fail to bring relief.
Serotonin vs Dopamine: Happiness vs Pleasure
Here’s another insight into a key difference between serotonin and dopamine.
Robert Lustig, MD, author of The Hacking of the American Mind, calls serotonin and dopamine the neurochemical pathways of “happiness” and “pleasure,” respectively.
Happiness and pleasure are similar, but there’s a fundamental difference.
Serotonin provides a contented kind of happiness.
It tells the brain, “This feels good and I have enough.”
Dopamine, as the reward chemical, encourages us to seek a hedonistic kind of happiness or pleasure.
It tells the brain, “This feels good and I want more.”
Dopamine temporarily gives you a good feeling when you accomplish a goal, eat food, drink coffee, take drugs, have sex, or engage in risky behaviors.
It’s easy to see how an excess of dopamine can get you into trouble.
Serotonin vs Dopamine Depression: How to Tell the Difference
The symptoms of depression, whether related to serotonin or dopamine, are very similar.
But there are a few distinctions.
Dopamine-related depression is characterized by lethargy and apathy, while serotonin-related depression is usually accompanied by feelings of anxiety.
People with dopamine-related depression often self-medicate with substances and activities that flood the brain with dopamine, such as excessive coffee, sugar, cigarettes, shopping, gambling, porn, and recreational drug use.
People with serotonin-related depression tend to consume excessively high-carbohydrate foods like ice cream and pastries which give them a short-lived surge in serotonin.
Men, in particular, are more likely to abuse alcohol if they are low in serotonin.
Depression May Not Be Due to a Serotonin Deficiency
If you’re depressed, your doctor will likely initiate your treatment with a selective serotonin reuptake inhibitor (SSRI).
SSRIs are the most commonly prescribed antidepressants and are thought to work by increasing serotonin levels in the brain.
These drugs, which include Prozac, Zoloft, and Lexapro, are the first-line treatment for depression.
Unfortunately, SSRIs work for only 40% of those who try them, so treating depression as a serotonin deficiency is clearly a protocol with limited success.
When Initial SSRI Treatment Doesn’t Work
Depression unresponsive to standard antidepressant medication is labeled as treatment-resistant depression.
When a patient doesn’t respond positively to the first SSRI, one of three things can happen.
Their doctor will increase the dosage, add an additional medication, or switch to a different antidepressant, usually a different SSRI.
Unfortunately, few doctors consider that dopamine, rather than serotonin, may be the problem instead.
Interestingly, when SSRIs do alleviate depression symptoms, it may not be for the expected reason.
There’s evidence that SSRIs may help depression by other mechanisms that have nothing to do with serotonin.
For example, it’s now thought that SSRIs may relieve depression by:
The Case for Dopamine Dysfunction as a Cause of Depression
The theory that dopamine contributes to depression isn’t new, but the medical community has largely overlooked it.
Numerous studies going back decades support the idea that dopamine dysfunction can be a cause of depression.
In the early 1990s, researchers found substantial evidence that drugs that target dopamine activity can effectively treat depression.
In 2005, Harvard Medical School researchers confirmed a link between depression and dopamine dysregulation.
Furthermore, a final piece of evidence implicating dopamine in depression is the group of antidepressants known to increase dopamine levels.
Doctors typically prescribe these drugs only after SSRIs have proven ineffective.
Bupropion
Bupropion (brand name Wellbutrin) is one of the better-known antidepressants that increases dopamine.
It is classified as a norepinephrine dopamine reuptake inhibitor (NDRI) since it increases both dopamine and norepinephrine, a dual-purpose chemical messenger that acts as both a stress hormone and a neurotransmitter.
Perhaps tellingly, NDRIs are classified as atypical antidepressants.
Monoamine oxidase inhibitors (MAOIs) cover all bases by blocking the activity of an enzyme that breaks down dopamine, serotonin, and norepinephrine, thereby raising the levels of all three of these neurotransmitters.
Doctors typically prescribe these drugs only after SSRIs have proven ineffective.
Bupropion (brand name Wellbutrin) is one of the better-known antidepressants that increases dopamine.
It is classified as a norepinephrine dopamine reuptake inhibitor (NDRI) since it increases both dopamine and norepinephrine, a dual-purpose chemical messenger that acts as both a stress hormone and a neurotransmitter.
Perhaps tellingly, NDRIs are classified as atypical antidepressants.
MAOIs: Neurotransmitter Regulators
Monoamine oxidase inhibitors (MAOIs) cover all bases by blocking the activity of an enzyme that breaks down dopamine, serotonin, and norepinephrine, thereby raising the levels of all three of these neurotransmitters.
The number and health of neurotransmitter receptors, along with whether neurotransmitters are appropriately broken down or recirculated, significantly impact neurotransmitter function.
So, for now, the best indicator of your serotonin and dopamine status is your symptoms.
Other factors that significantly impact neurotransmitter function include the number and health of neurotransmitter receptors, as well as the appropriate breakdown or recirculation of neurotransmitters.
So, for now, the best indicator of your serotonin and dopamine status is your symptoms.
One additional type of supplement to look into is a psychobiotic formula.
Psychobiotics are probiotics that specifically bestow mental health benefits.
The microbes that dwell in the intestines produce over 30 neurotransmitters, including dopamine and serotonin.
Remarkably, your intestines house 90% of your total serotonin and 50% of your total dopamine.
Warnings About 5-HTP for Depression
5-HTP (5-hydroxytryptophan) is a popular supplement for depression, insomnia, and anxiety.
Many mood-enhancing supplement formulas contain 5-HTP as an active ingredient.
5-HTP increases serotonin, but does so at the expense of dopamine.
This is why supplementing with 5-HTP typically helps in the beginning, but eventually stops working.
If you take 5-HTP for more than a few months, you’re trading one neurotransmitter imbalance for another.
If you decide to try it, remember never to take 5-HTP with antidepressants or other supplements that increase serotonin.
Together, they can cause serotonin levels to get too high and even cause a potentially serious condition known as serotonin syndrome.
If you aren’t sure whether any drugs or supplements you take contribute to high serotonin levels, check out Medications That Raise Serotonin Levels, a comprehensive list of substances that increase serotonin, created for us by Drugwatch.com.
Recommended: Upgrading brain health is key to making your brain work better.
Brain supplement can help you:
- Improve your mental clarity and focus.
- Boost your memory and your ability to learn.
- Increase your capacity to think critically, solve problems, and make decisions.
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