What Do Antidepressants Do to the Brain?

January 10, 2022

Nue Life

Nue Life

Top points

  • Antidepressants increase various neurotransmitters in your brain that are involved in mood regulation.
  • They can also cause side effects such as concentration problems and out-of-control emotions.
  • Ketamine has minimal side effects and acts differently on the brain, creating new neural pathways so you can change negative thought patterns.

If you struggle with your mental health, the odds are you’ve thought about taking antidepressants. In recent years, antidepressants have become one of the most commonly used treatments for a myriad of mental health conditions.

However, how much do we know about how antidepressants really work? It’s common to ask questions like “How do antidepressants affect your brain?”, “What are the mental side effects of antidepressants?” or “Can antidepressants cause permanent changes?”

Being aware of how antidepressants affect your brain chemistry will better inform you on whether or not they’re the right choice for you.

At this point, scientists know that antidepressants have successfully treated some people’s mental health conditions, but they still aren’t entirely sure how the medications do so. In this article, we’ll explore the popular theories on how they work, their common side effects, and alternatives to antidepressants.

Many theories circulate in the medical community as to how antidepressants work. One is that antidepressants may correct a chemical imbalance in people with lower levels of neurotransmitters.

How Does Your Brain Work?

The brain is a complex system containing several billion nerve cells used to coordinate functions like behavior, touch, thought, emotions, and movement.

These nerve cells, also known as neurons, coordinate these functions by communication sent throughout the body within a split second — just like when you quickly react to touching something too hot.

That is communication being received by the nerves in your hand and sent up to the brain. The brain receives it and sends a message to quickly move the hand.

This happens in one moment by neurons communicating with other cells. Neurons communicate by using electrical pulses to create neurotransmitters, which essentially act as messengers of information to other chemicals in the body.

What Do Neurotransmitters Do?

Neurotransmitters essentially bring messages to and from your brain. Between each neuron is a gap called a synapse.

Neurotransmitters receive information from one neuron, then travel through the synapse to deliver the information to the next neuron. This process continues throughout the body, allowing you to communicate, have emotions, and process the world around you.

There are over fifty different types of neurotransmitters, and they have three different types of influence on neurons. The three types of influencers include the following:

Modulatory neurotransmitters
Excitatory neurotransmitters
Inhibitory neurotransmitters

Among the fifty different types of neurotransmitters, one of the main ones is monoamines. This type of neurotransmitter is specifically important because it directly deals with how you make decisions, respond emotionally, and general moods such as overall happiness and emotional wellness.

Some examples are serotonin, dopamine, and norepinephrine.


Serotonin is not only an important hormone, but it also can act as an inhibitory neurotransmitter. Instead of stimulating the brain, it works to bring balance by counteracting excitatory neurotransmitter effects.

Serotonin plays a crucial role in balancing emotions and regulating sleep cycles, appetite, subduing stress and tension, and controlling discomfort. Serotonin can typically be located in the central and enteric nervous systems.

There are several adverse outcomes to someone experiencing a lack of serotonin. These include major mental health conditions, leading to general fatigue, persistent sadness, or potentially thoughts of self-harm.


Unlike the inhibitory neurotransmitter serotonin, dopamine is actually all three different types of neurotransmitters. It is a modulatory, excitatory, and inhibitory neurotransmitter. Relating to the reward function of the brain, dopamine plays a significant role when it comes to tasks like motivation, addiction, and other reward-based behaviors.

Too much dopamine can lead to aggression, addiction, an overly competitive nature, and a lack of control over your reactions. Inversely, a lack of dopamine in the body can lead to feelings of restlessness and other similar symptoms.

Most addictive drugs are known to raise levels of dopamine. Once your body becomes used to a heightened amount of dopamine, the reward part of the brain will send signals to your body to take more, furthering the cycle of addiction.

Once the cycle has begun, ending the use of the drugs will lead to less dopamine than your body is used to, thus potentially leading to depressive symptoms.


Norepinephrine, also called noradrenaline, is an excitatory neurotransmitter that occurs naturally within the adrenal glands, hypothalamus, and brain stem. Its primary function is to bring stimulation to the body and brain.

This function allows the body and brain to recognize stress and danger and react accordingly. It essentially curates alertness as a natural protective instinct. This reaction is commonly known as the fight-or-flight response.

While stressful situations heighten norepinephrine, it is at its lowest point during times of sleep and rest. If levels become higher than necessary, this may result in stress, tension, and high blood pressure. If they are too low, it is likely to result in trouble concentrating, a lack of overall energy, and symptoms of poor mental health.

How Do Antidepressants Affect Your Brain?

While antidepressants have been around for decades, the exact way they affect a person’s brain has remained elusive. What researchers do know is that most antidepressants are considered to be reuptake inhibitors. The brain’s natural function uses brain cells to create certain molecules to recycle leftover neurotransmitters by catching them in synapses.

These molecules are able to catch neurotransmitters because they have an exact slot for them to fit in. Certain uptake inhibitors work by moving into these slots before the neurotransmitters, thus blocking their entry and leaving them to stay in synapses. This can lead to the development of neighboring cells.


Selective serotonin reuptake inhibitors are found in some of the more popular antidepressants. Their main function is in the name. They inhibit the reuptake of serotonin in the body to ultimately increase the action of serotonin.

SSRIs are not like any other antidepressant in the way they do not interfere much with the movement of any other neurotransmitters such as dopamine and norepinephrine. They also get their popularity because of the lack of side effects compared to different types of antidepressants.

Here are some popular FDA approved SSRIs that are currently used to treat several mental health conditions:

• Fluoxetine
• Fluvoxamine
• Escitalopram
• Sertraline
• Citalopram
• Paroxetine


Serotonin and norepinephrine reuptake inhibitors work much like SSRIs in the way that they enter into molecules blocking neurotransmitters from moving in and leaving them in the synapses.

The main difference between SSRIs and SNRIs is that SNRIs also inhibits the reuptake of norepinephrine and serotonin. Both SSRIs and SNRIs are mainly used to treat stress and tension. The side effects of this type of antidepressant can include nausea, dizziness, drowsiness, and sexual dysfunction.

Here are several FDA approved SNRIs that are currently being used to treat depressive symptoms:

• Cymbalta
• Pristiq
• Effexor


Norepinephrine and dopamine reuptake inhibitors work similarly to SNRIs and SSRIs by blocking norepinephrine and dopamine so that the brain can retain more of those specific neurotransmitters.

This change to the brain’s functionality over time could relieve conditions such as depressive symptoms. Because of the roles that norepinephrine and dopamine play in the function of the human brain, taking NDRIs can result in overall quick and straightforward reactions when placed into stressful situations and better motivation and reward response to certain aspects of life.

Side effects include weight loss, sleep issues, dry mouth, and excessive stress.


Tricyclic antidepressants, named after the number of rings that make up their chemical structure, are an older type of antidepressant—tricyclics focus on blocking the reuptake or absorption of two different neurotransmitters — serotonin and norepinephrine.

Ultimately, the goal is to raise those levels to relieve feelings of restlessness and manage overall mood. These cyclic antidepressants can also affect several chemical messengers, which can cause several unwanted side effects like drowsiness, blurred vision, weight loss, and sexual dysfunction.

Here are several FDA approved TCAs that are currently being used to help support treatment for symptoms:

• Desipramine
• Amoxapine
• Trimipramine
• Nortriptyline
• Doxepin


Serotonin antagonists and reuptake inhibitors work to increase the amount of serotonin in the brain by targeting a specific receptor of serotonin called the 5HT2a receptor and blocking the absorption, or reuptake, of serotonin.

Different types of this antidepressant can also affect other essential activities in the brain and neurotransmitters, such as blocking the reuptake of norepinephrine and potentially causing adrenergic and histamine blockades.

Initially used as an antidepressant, SARIs are now mainly used by individuals struggling with sleep quality and symptoms of stress and tension.

The main side effects include headaches, dry mouth, constipation, and withdrawal symptoms when ceasing drug intake.


In the 1950s, monoamine oxidase inhibitors were the very first antidepressant medication to come out. They have proven to be effective but now are seldom prescribed due to the safety of other antidepressants in having significantly fewer side effects.

MAOIs have specific dietary and medical requirements. When taking them, you have to be careful about what you put into your body because when mixed with the wrong food or medication, MAOIs can cause severely high blood pressure.

MAOIs operate by interfering with a specific enzyme called monoamine oxidase, which removes all three neurotransmitters — dopamine, serotonin, and norepinephrine — from the brain.

The main side effects include nausea, bowel movement issues, weight gain, and sleep health. Here are several FDA-approved MAOIs that are currently being used to treat depressive symptoms:

• Selegiline
• Phenelzine
• Tranylcypromine
• Isocarboxazid

What Are The Mental Side Effects Of Antidepressants?

Some side effects may vary depending on what type of antidepressant you are taking. There are many physical side effects that occur from each one, but there are also plenty of mental side effects to be aware of.

The primary function of antidepressants is to increase certain neurotransmitters in your brain to encourage usual functionality. The neurotransmitters directly affect things such as mood, alertness, emotions, and concentration.

You could experience heightened emotions, reduced alertness, inability to control mood, and lack of ability to concentrate, among many other variations of these issues.

The FDA requires each antidepressant to come with a black box warning label informing the user that, in some cases, the drugs have led to an increase of harmful thoughts among people under the age of 25.

Can Antidepressants Cause Permanent Changes?

As of August 2019, according to Alexander S. Young, there is no compelling reason to believe that antidepressants can cause permanent changes in the brain. While there is limited research on the matter, Young claims that there is little reason to believe that they would cause permanent change based on clinicians’ experience on the subject.

Are There Alternatives To Antidepressants?

The use of ketamine treatments has become a primary alternative to antidepressant medication. What started as an anesthetic for the numbing of discomfort has become one of the medical world’s most exciting ways to help support emotional wellness.

Ketamine infusions are holistic and come with little to no side effects. It works by restoring the synapse connection in your brain that stress can break down over time, ultimately pathing healthier thought patterns and brain activity.

Nue Life offers affordable, at-home ketamine experiences that help patients uncover valuable insights in their mental wellness journey. These breakthroughs are later supported through compassionate support from a dedicated team of clinicians and wellness experts.


There are several different types of antidepressants. They are all meant to inhibit the reuptake, or absorption, of certain neurotransmitters from keeping them present in the brain.

The ultimate goal is to restore the natural functionality of those neurotransmitters and bring balance to those functions of the brain. Taking antidepressants comes with the potential for several physical and mental side effects.

In some cases, it even worsens the original symptoms. However, there are holistic alternatives to taking antidepressants that have been proven to be less risky and have more efficient outcomes.

With the help of evidence-based treatments and products, Nue Life aims to help patients discover and grow into their most authentic selves.


Neurotransmitters: Types, Function, and Examples | Simply Psychology

Antidepressants and Brain Neurochemistry | Mayo Clinic

Selective Serotonin Reuptake Inhibitors | NCBI

Tricyclic Antidepressants and Tetracyclic Antidepressants | Mayo Clinic

Serotonin Antagonist and Reuptake Inhibitor (SARI) | American Addiction Centers

Selective Serotonin Reuptake Inhibitors (SSRIs) | Mayo Clinic

What are the long-term effects of common antidepressant medications, such as SSRIs or SNRIs? Do they cause permanent changes? | SMI Advisor

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