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Selective Serotonin Reuptake Inhibitors (SSRIs) | Overview & Side Effects

Published on October 15, 2021
Selective Serotonin Reuptake Inhibitors (SSRIs) | Overview & Side Effects

Selective serotonin reuptake inhibitors (SSRIs) are the most widely prescribed class of antidepressants. Although they mainly treat depression, SSRIs are also used to treat anxiety and other mental health disorders

SSRIs are likely the first course of treatment for depression because they cause fewer side effects than other antidepressants. The most common side-effects associated with SSRIs include sexual dysfunction, difficulty sleeping, and weight changes. 

SSRIs & Antidepressants

Major depression, also referred to as major depressive disorder, is a serious mental health disorder that affects about 16 million adults each year. 

Symptoms of depression involve feelings of sadness that persist for at least two weeks and interfere with daily life. Untreated depression increases the risk of suicidal thoughts or substance abuse to self-medicate. 

Along with depression, SSRIs may also be used to treat:

The treatment of depression usually involves medication, therapy, or a combination of both. Antidepressant medications have been around for decades but one of the most recent types, SSRIs, have been found to be less harmful. 

SSRI antidepressants include:

Other types of antidepressants include:

  • monoamine oxidase inhibitors (MAOIs)
  • tricyclic antidepressants
  • serotonin-norepinephrine reuptake inhibitors (SNRIs)
  • atypical antidepressants

Tricyclic antidepressants and MAOIs are older types of antidepressants that are associated with more severe side effects. They are usually only prescribed if SSRIs or other types of antidepressants are ineffective. 

SSRIs Side Effects

Depression is a complex disorder with many possible causes. However, it is believed that the neurotransmitters (chemical messenger) dopamine, norepinephrine, and serotonin may play a role in depression. 

How SSRIs Work

SSRIs target serotonin, which is responsible for regulating mood, emotions, and appetite. As a neurotransmitter, serotonin carries messages between neurons (nerve cells). Serotonin is then reabsorbed before another signal can be transmitted, also known as “reuptake.” 

SSRIs block the reuptake of serotonin, which increases levels of serotonin in the brain. This may improve depression symptoms for some people, however, SSRIs can take several weeks to be effective. 

During this period, side effects may peak as your body adjusts to the medication. Your doctor may start you at a low dose and increase it slowly as needed. 

Learn more about How SSRIs Work

Common Side Effects

Not everyone will experience adverse effects and some people may experience worse side effects than others. If side effects are severe, your prescribing doctor may recommend a different medication or class of antidepressants. 

Although all SSRIs work similarly, they vary in their chemical makeup. SSRIs differ in how long they last in your body, how they interact with other drugs, and the effectiveness of the recommended dose. These differences can influence side effects of each individual drug. 

Common side effects of SSRIs include:

  • nausea/vomiting
  • diarrhea
  • headache
  • drowsiness
  • dry mouth
  • insomnia
  • anxiety
  • dizziness
  • erectile dysfunction
  • changes in appetite

Long-term use of SSRIs is associated with sexual dysfunction, weight gain, and sleep problems. 

Some SSRI drugs carry a higher risk of sexual side effects and insomnia than other drugs. In addition, weight gain is often attributed to the medication but may also be affected by lifestyle changes during and after depression episodes. 

Serious Side Effects Of SSRIs

For some people, the benefits of SSRIs outweigh the risk of side effects. However, it is important to watch for signs of serious side effects. If you recognize signs of serious side effects, you should seek medical attention immediately.

Increased Risk Of Suicidal Thoughts/Behavior

The U.S. Food and Drug Administration (FDA) requires a warning on the label of all antidepressant drugs, including SSRIs. Clinical trials found an increase in suicidal thoughts and behaviors during the initial months of treatment. Studies have found this risk mainly affects children and adolescents.

Children and adolescents being treated for depression should be monitored daily for the following warning signs:

  • agitation
  • irritability
  • suicidal thoughts/behaviors
  • behavior changes

To decrease the risk of suicidality, healthcare professionals will typically begin treatment with a low dose. Families and doctors can work together by keeping open communication about warning signs and unusual changes in mood or behavior. 

If you notice signs of suicidal thoughts or behaviors in a loved one, seek emergency care immediately. 

Serotonin Syndrome

Although serotonin is a necessary and natural hormone, too much can be life-threatening. 

Serotonin syndrome is a condition that occurs when you take one or more medications that affect serotonin levels. If you take high doses of SSRIs or multiple medications that target serotonin, it can cause a toxic buildup of the chemical in your system. 

Symptoms can range from mild to severe and may include: 

  • agitation
  • confusion
  • fast heart rate
  • muscle twitching
  • sweating 
  • diarrhea
  • shivering
  • headache

In life-threatening cases, serotonin syndrome can cause a fever, seizures, irregular heartbeat, and loss of consciousness. 

Drugs that may interact with SSRIs and increase the risk of serotonin syndrome include:

  • MAOIs
  • tricyclic antidepressants
  • SNRIs
  • migraine medications
  • opioids
  • recreational drugs (like ecstasy and LSD)
  • amphetamines
  • herbal supplements (like St. John’s Wort)

If you show any signs of serotonin syndrome, you should speak with a healthcare professional immediately. Mild cases may be treated by stopping the medications that enhance serotonin, while severe cases may require hospitalization. 

Learn more about the Short & Long Term Side Effects Of SSRIs

To learn more about how Ark Behavioral Health supports treatment for mental health disorders, please speak with a specialist today. 

Frequently Asked Questions About SSRIs

What Are Some Examples Of SSRI Medications?

Some of the most common SSRIs include:

  • citalopram (Celexa)
  • escitalopram (Lexapro)
  • fluoxetine (Prozac)
  • paroxetine (Paxil)
  • sertraline (Zoloft)
  • vilazodone (Viibryd) 

To learn more, read List Of SSRI Medications

What Is The Newest SSRI Available?

Trintellix (vortioxetine) is the newest SSRI available and was approved by the FDA in 2013. As an SSRI, Trintellix blocks the reabsorption of serotonin, which increases the amount of this chemical in the brain. 

Serotonin is an important hormone responsible for mood, emotions, and well-being. SSRIs have been among the most successful types of antidepressants. Trintellix and other SSRIs cause fewer adverse side-effects than other medications. 

Learn more about The Latest Antidepressants

Are SSRIs Effective For Treating Anxiety?

SSRIs are likely the first-line of defense for those who struggle with anxiety disorders. However, since these reuptake inhibitors only affect serotonin, there are other types of antidepressants that may be better for you. 

Learn more about Using SSRIs To Treat Anxiety Disorders

Do SSRIs Cause Weight Gain?

Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressant drugs. One of the most common side-effects associated with all antidepressant drugs is weight gain. 

Some SSRIs are associated with a risk of weight gain, especially if the drug is taken long-term. Some studies have found an average increase of about 20 pounds, depending on the medication. 

In some cases, however, weight gain can be caused because the medication is improving depression and appetite is normalizing. Other factors, like smoking and lack of exercise, can also contribute to weight gain. 

Learn more about SSRIs & Weight Gain

Are SSRIs Effective For Treating OCD?

Some SSRIs are effective for treating obsessive-compulsive disorder (OCD), but not all SSRIs are helpful as some work better than others. Prozac and Zoloft are two of the most well-known SSRIs used to treat OCD.

Learn more about Using SSRIs To Treat OCD

How Long Does It Take For SSRIs To Work? 

SSRIs can take between four to six weeks to start working for depression. Health experts are debating on why SSRIs do not improve your mood right away.

To learn more, read How Long Does It Take For SSRI Antidepressants To Work?

What’s The Difference Between SSRIs & SNRIs?

Selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) are antidepressants. They are used primarily for anxiety disorders. 

SNRIs seem to be more effective than SSRIs, but they may have more side effects that some find difficult. SSRIs are likely used as the first-line of defense against an anxiety disorder. 

SSRIs are selective and increase serotonin in the brain while SNRIs increase both serotonin and norepinephrine. 

Learn more about SSRIs Vs. SNRISs

Is It Risky To Take SSRIs Long-Term?  

While SSRIs are considered a safe option for treating major depressive disorder and certain mental health conditions, there are certain risks that those using SSRIs should be aware of, especially with prolonged use. 

Learn more about the Risks & Dangers Of SSRI Antidepressants

What Are Some Alternatives To SSRIs? 

Alternatives to SSRIs include SNRIs, antipsychotics, ketamine, psychotherapy, and exercise. The most effective treatment for depression may be different for everyone.

Learn more about the Alternatives To SSRI Antidepressants

Can You Take SSRIs During Pregnancy?

No study has shown conclusive evidence that taking SSRIs during pregnancy will harm the baby. While there is a slight increase in risk of birth defects, it’s so small that it’s unclear whether the SSRIs are the cause.

Learn more about SSRI Antidepressants & Pregnancy

Written by Ark Behavioral Health Editorial Team
This page does not provide medical advice.

Centers For Disease Control And Prevention (CDC) - Mental Health Conditions: Depression and Anxiety
Food And Drug Administration (FDA) - Suicidality in Children and Adolescents Being Treated With Antidepressant Medications
National Library of Medicine: StatPearls - Selective Serotonin Reuptake Inhibitors
The Primary Care Companion to the Journal of Clinical Psychiatry - SSRI Antidepressant Medications - Adverse Effects And Tolerability

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