Serotonin (A complete guide)

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Serotonin is a neurotransmitter produced in the brain that is heavily involved in regulating mood, sleep, appetite, and more. 

Neurotransmitters are chemical messengers in the brain that relay information to other neurons, or nerve cells.

They are molecules that transmit messages between neurons and neurons to muscles by our nervous system. 

In this blog article, we will go over how serotonin is involved in many aspects of our mood and daily functioning, and how it is dysregulated in certain psychiatric disorders. 

What is serotonin?

Serotonin, sometimes abbreviated as 5-HT, is a neurotransmitter that controls many aspects of our daily functioning including mood, appetite, and sleep.

Dysfunction in the 5-HT system has been implicated in the pathogenesis of depression.

Insufficient amounts of serotonin may play a role in anger issues and even suicidal tendencies.

Typical antidepressants work by increasing the amount of serotonin available in the synapse. 

Some facts about serotonin: 

·      There are many different types of serotonin receptors, and the effects are usually inhibitory

·      It is released mainly from neurons in the brainstem.

·      The main function of serotonin is to regulate the body temperature, emotions and the sleep cycle.

Although there are many other factors involved in the etiology of depression, anxiety, and other mental disorders, it has been shown over the past several decades that serotonin levels are reduced in patients with these disorders.

Thus, medications to increase the levels of serotonin in the brain are commonly used to treat many of these conditions. 

Selective serotonin reuptake inhibitors (SSRIs) are a type of drug that are used to treat various mental disorders including depression.

As they have been found to diminish experiences of moderate to severe depression, selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants.

They are relatively safe and often lead to fewer side effects in comparison to other types of antidepressants that would be used for the same purpose.

How do SSRIs work?

SSRIs treat depression by increasing the amount of the chemical serotonin in the brain.

Serotonin is one of the chemical messengers (neurotransmitters) that deliver signals between brain nerve cells (neurons).

SSRIs hinder the reabsorption (reuptake) of serotonin into neurons.

This allows more serotonin to be available so that it can help facilitate the transmission of information and messages between neurons.

SSRIs are called selective because they mainly affect serotonin, not other neurotransmitters.

Aside from depression, SSRIs may also be used to treat other conditions such as anxiety disorders.

SSRIs approved to treat depression

The Food and Drug Administration (FDA) has approved these SSRIs to treat depression:

  • Citalopram (Celexa)
  • Escitalopram (Lexapro)
  • Fluoxetine (Prozac)
  • Paroxetine (Paxil, Pexeva)
  • Sertraline (Zoloft)

What are possible side effects and cautions to be aware of before taking SSRIs?

Scientific research has found that all SSRIs have similar ways of functioning and usually can lead to similar side effects, which not all people experience in the first place.

After the first few weeks of beginning SSRI treatment, many of the potential side effects that you may experience will subside.

However, if the side effects persist you should notify your doctor and request to try a different drug to treat your malady. 

SSRIs vary in their rate of blocking serotonin reuptake and how fast the body metabolizes the drug, so if you can’t tolerate one SSRI, your body still could respond positively to another SSRI that is different from the SSRI that you are unable to tolerate.

Among others, possible side effects of SSRIs may include:

  • Nausea, vomiting or diarrhea
  • Headache
  • Drowsiness
  • Dry mouth
  • Insomnia
  • Nervousness, agitation or restlessness
  • Dizziness
  • Sexual problems, such as reduced sexual desire, difficulty having a release or inability to maintain an erection (erectile dysfunction)
  • Impact on appetite, leading to weight loss or weight gain

To reduce your risk or experiences of nausea, try taking your medication with food.

Also, as long as your medication does not hinder your sleeping, you can minimize the effect of nausea by taking your SSRI when you head to bed.

Your symptoms and pre existing health conditions determine which antidepressant is best for you.

Ask your doctor and pharmacist about the most common possible side effects for your specific SSRI and fully read the patient medication guide that comes with the prescription.

Stopping treatment with SSRIs

Luckily, SSRIs aren’t addictive. However, withdrawal-like symptoms can appear if one abruptly terminates antidepressant treatment abruptly or repeatedly misses several doses.

This phenomenon is sometimes called discontinuation syndrome.

Work with your doctor to gradually and safely decrease your dose.

Withdrawal-like symptoms can include:

  • General feeling of uneasiness
  • Nausea
  • Dizziness
  • Lethargy
  • Flu-like symptoms

How do I find the right serotonin medication for me?

The same antidepressant may affect different people in different ways, causing varying reactions.

For example, a specific SSRI may work better — or not as well — for you than for another person.

Or you may have more, or fewer, side effects from taking a specific antidepressant than someone else does.

Genetically inherited traits also are a factor in how antidepressants affect you.

If you have a close relative who had a negative experience using a particular antidepressant, tell your doctor, because this drug should be avoided.

Likewise, if you have a close relative who had a positive experience using a particular antidepressant, tell your doctor, because this drug could be a good starting point.

In some cases, results of special blood tests, if available, can offer clues about how your body may respond to a particular antidepressant.

However, other variables do affect your response to medication.

When deciding which antidepressant to take, your doctor should consider your symptoms, any health problems, other medications you take and what has worked for you in the past.

Often, it can take several weeks or longer before an antidepressant is fully effective and for initial side effects to halt.

Your doctor may recommend some dose adjustments or different antidepressants, but with patience, you and your doctor can find a medication that works well for you.

Who should take medications that increase serotonin levels?

If you suspect you have MDD, SAD, an anxiety disorder, or another related condition, talk to your doctor about taking antidepressants.

In addition, a loved one or friend may reach out to discuss these symptoms with you and point you in the direction of help.

These are debilitating mental health conditions and you should not feel like you have to go through them alone. 

MDD is a mood disorder that causes feelings of worthlessness and loss of interest in daily activities.

Common symptoms of MDD are as follows: 

·      Chronic feelings of sadness, tearfulness, emptiness, or hopelessness

·      Loss of interest in activities that once used to bring enjoyment (i.e., sex, hobbies) 

·      Outbursts of anger 

·      Irritability

·      Frustration

·      Issues with sleeping too much or insomnia

·      Lack of energy and fatigue 

·      Changes in eating patterns and weight (i.e., increased appetite and weight gain or reduced appetite and weight loss)

·      Anxiety

·      Agitation

·      Restlessness

·      Slowed speaking, thinking, and movement 

·      Feelings of worthlessness 

·      Ruminating on past failures

·      Feelings of guilt 

·      Trouble concentrating, making proper decisions, and remembering things 

·      Physical problems such as back pain or headaches that cannot be explained by another medical condition 

SAD is a subtype of depression that is heavily related to changes in seasons.

It usually begins at the same time every year and usually occurs during fall and winter months.

If you have any of the following symptoms, you may be diagnosed with SAD: 

·      Feelings of depression most of the day almost every day

·      Low energy

·      Loss of interest in activities that used to bring enjoyment

·      Trouble sleeping, usually oversleeping 

·      Changes in appetite or weight 

·      Feelings of hopelessness, worthlessness, or guilt

·      Feeling agitated or sluggish 

·      Frequent thoughts of death or suicide

In the winter months, people with SAD may frequently oversleep, gain weight due to food cravings high in carbohydrates, or have fatigue and lack of energy.

More rarely, people can suffer from SAD in the spring or summer months.

These patients are likely to experience trouble sleeping (insomnia), reduced appetite and weight loss, and agitation or anxiety. 

Side Note: I have tried and tested various products and services to help with my anxiety and depression. See my top recommendations here, as well as a full list of all products and services our team has tested for various mental health conditions and general wellness

Want to learn more about antidepressants? Try these books!

Medications for Anxiety & Depression – A no-nonsense, comprehensive guide to the most common (and not so common) antidepressants and anti-anxiety drugs available

If you are suffering from major depressive disorder (MDD), including treatment resistant depression and dysthymia, generalized anxiety disorder (GAD), panic disorder, phobic disorder, obsessive compulsive disorder (OCD), or any mood disorder on the depressive or anxious spectrum, this book is for you.

It is important to understand which medications might be prescribed to you and how they work, as well as common side effects.

Benjamin Kramer provides extensive details on common and non-common antidepressants and anti-anxiety medications (anxiolytics) including SSRIs (selective serotonin reuptake inhibitors, such as Zoloft, Paxil, Prozac and Lexapro), SNRIs (Serotonin and Norepinephrine reuptake inhibitors such as Effexor and Cymbalta), atypical antidepressants (such as Remeron, Buspar and Wellbutrin), TCAs (Tricyclic antidepressants, such as Endep and Anafranil), Benzodiazepines (such as Xanax, Ativan and Klonopin), “Off-label” and experimental options including stimulants (amphetamine, methylphenidate), Lyrica, tramadol memantine and ketamine.

This book also discusses upcoming drugs for depression and anxiety that are supposed to become available soon. 

Understanding Antidepressants

Dr. Wallace B. Mendelson, Professor of Psychiatry and Clinical Pharmacology at University of Chicago, explains how antidepressants work, their interactions with other medications, how long they stay in the body, side effects, and what to consider when choosing one.

About 10% of the population in the United States is taking antidepressants, and about 16 million Americans experience a major depressive episode each year, so it is important to thoroughly understand how this condition is treated. 

The Mindfulness Journal: Daily Practices, Writing Prompts, and Reflections for Living in the Present Moment

As described above, journaling is a great way to give yourself a stress release.

Whether you are dealing with mental health issues, heartbreak, a problem at work, or any other life stressor, this journal is for you.

This Mindfulness Journal can easily be added into your daily routine and can serve as an outlet for stress-reduction that will help you appreciate every single day and moment.

It includes 365 daily writing prompts divided into 52 weekly mindfulness topics.

The prompts are extremely unique, fun, and engaging, so you will never get bored while journaling.

Additionally, each prompt is on its own separate page so you will have more than enough room for reflection and to write down all of your thoughts, big or small.

Although it is suggested to journal once a day, you can spend as much or as little time as you want on each prompt. 

I am not in recovery. I am in discovery: Journaling my mental illness

Journaling is a great way to help process and keep track of your experiences and feelings while you are going through depression or seasonal affective disorder (SAD).

This journal contains 94 daily templates to aid in your discovery process. 

In this blog article, you should have learned about the different types of antidepressants, how they work to treat depression and anxiety, and common side effects. 

Better Living Through Neurochemistry – A guide to the optimization of serotonin, dopamine and the neurotransmitters that color your world

James Lee provides an in depth overview of what neurotransmitters are, what they do in your brain and body, and how to boost levels.

This book also explains how to know when certain neurotransmitters are depleted. 


Antidepressants: Selecting one that’s right for you. Mayo Clinic

Selective Serotonin Reuptake Inhibitors (SSRIs) Information, U.S. Food and Drug Administration

What are SSRIs?,WebMD

Selective Serotonin Reuptake Inhibitors: What to Know, Health Line


What are neurotransmitters? Queensland Brain Institute. November 9th, 2017. 

The Brain from Top to Bottom. McGill University. 2020  

What are neurotransmitters. Medical News Today. 2020. 

Can a Neurotransmitter Imbalance be Causing Your Mood Problems? Integrative Psychiatry. 2020 

Olivia Levine (neuroscientist, neuroscience PhD candidate) 


What are neurotransmitters? Queensland Brain Institute. November 9th, 2017. 

The Brain from Top to Bottom. McGill University. 2020  

What are neurotransmitters. Medical News Today. 2020. 

Can a Neurotransmitter Imbalance be Causing Your Mood Problems? Integrative Psychiatry. 2020 

Olivia Levine (neuroscientist, neuroscience PhD candidate) 

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