Selective-Serotonin Reuptake Inhibitors (SSRIs)

This article provides a comprehensive overview of SSRIs, including the benefits, common examples, side effects, and their overall role in depression and mental health treatment.

Key Takeaways

• SSRIs are the most commonly prescribed type of antidepressant. In addition to depression, they’re also used for anxiety disorders and several other conditions.

• SSRIs are generally tolerated better and are less likely to cause side effects compared to other antidepressants. However, there are still several possible side effects and interactions, some of which may be severe.

• SSRI treatment involves a trial period (over several weeks), typically followed by at least 6 months of use. Regular visits with your doctor help formulate the most effective treatment plan.

Understanding SSRIs

Selective-serotonin reuptake inhibitors (more commonly referred to as SSRIs) are a specific class of antidepressant used primarily for depression and anxiety disorders. They are the most commonly prescribed type of antidepressant, mainly due to their established safety, tolerability, and effectiveness. SSRIs are considered a first-line treatment for depression and several other mental health conditions, particularly for people with moderate to severe symptoms. ^{[1] [2]}

How do SSRIs Work?

SSRIs work in part by inhibiting the reuptake of serotonin, which leads to more available serotonin in the brain. Serotonin is a neurotransmitter with important roles in mood and emotional regulation, sleep, appetite, and sexual function. Therefore, greater serotonin is thought to deliver antidepressant effects and reduce many of the hallmark symptoms of depression. ^{[1] [2]}

However, the serotonin deficiency or “chemical imbalance” theory of depression is not the full picture. Later research has found that antidepressants may have other benefits too, such as promoting nerve cell health and brain plasticity. This is important since these factors are often involved in depression, too, as opposed to only low levels of neurotransmitters. ^[3]

SSRIs to Treat Depression

There are many available SSRIs to treat depression. The most common ones are: ^{[1] [2] [4]}

• Fluoxetine (Prozac®)

• Sertraline (Zoloft®)

• Citalopram (Celexa®)

• Escitalopram (Lexapro®)

• Paroxetine (Paxil®, Pexeva®)

• Fluvoxamine (Luvox®)

Fluoxetine was the first approved SSRI back in 1988. It is used for major depressive disorder (MDD), treatment-resistant depression, bipolar depression, and several other mental health conditions. It acts the least directly on serotonin out of the SSRIs, and may also affect norepinephrine and dopamine at higher doses. ^[4]

Sertraline is approved for MDD, premenstrual dysphoric disorder (PMDD), and several other mental health conditions. It has relatively quicker-acting effects compared to other SSRIs, and it is one of the most commonly used SSRIs overall. ^[4]

Citalopram and escitalopram are used for MDD, and escitalopram is also used for anxiety. Escitalopram acts the most directly on serotonin out of all of the SSRIs, and may be more effective than citalopram. ^[4]

Paroxetine is used for MDD, PMDD, and other mental health conditions, especially anxiety disorders. It has some of the most direct and potent effects out of all of the SSRIs. ^[4]

Fluvoxamine is primarily used to treat obsessive-compulsive disorder (OCD), but it can be used for other anxiety or depressive disorders in some cases. Like paroxetine, fluoxetine also has potent effects. It also acts on sigma-1 receptors, which may lead to cognitive benefits. ^[4]

Another medication that has SSRI activity but is not as commonly prescribed is Vilazodone (Viibryd®). It is both an SSRI and a serotonin-receptor partial agonist. Both of these effects may have a positive effect on serotonin. It is primarily used for MDD.

Other Conditions Treated by SSRIs

In addition to depressive disorders, SSRIs are often used for other mental health conditions, such as: ^{[1] [2] [4] [5]}

• Panic disorder

• Generalized anxiety disorder (GAD)

• Post-traumatic stress disorder (PTSD)

• Social anxiety disorder (SAD)

• OCD

• Bulimia nervosa

SSRIs are also sometimes used off-label for other conditions, such as: ^{[1] [2] [4]}

• Chronic pain

• Gastrointestinal (GI) disorders, such as irritable bowel syndrome (IBS)

• Menopausal symptoms

• Binge eating disorder (BED)

• Premature ejaculation

Common Side Effects of SSRIs

SSRIs generally have fewer side effects compared to other types of antidepressants. However, there are still several potential side effects, such as: ^{[1] [2] [3] [4] [5]}

• Sexual problems

• Decreased libido

• Delayed orgasm

• Insomnia/sleep disruption

• Headache

• Anxiety

• Dizziness

• Headache

• Weight changes, esp. weight gain

• Appetite changes

• GI issues

• Nausea

• Vomiting

• Constipation

• Diarrhea

• Drowsiness

• Agitation

Rare and Severe Side Effects

There are also several less common side effects of SSRIs, some of which can be severe. This includes: ^{[1] [2] [4]}

• Serotonin syndrome: This is when too much serotonin builds up in the brain and nervous system. It can lead to severe symptoms, such as seizures, rapid heart rate, and disorientation. Other symptoms include: ^{[1] [2] [4]}

• Nervousness

• Dilated pupils

• Muscle twitching

• Sweating

• Side-to-side eye movements

• Diarrhea, nausea, and/or vomiting

• QT Prolongation: This disrupts the natural heart rhythm, which can be fatal in severe cases.

• Hyponatremia (low blood sodium)

• Cataracts

• Suicidal ideation: This is more likely to occur in children and young adults under age 25.

• Contact your doctor immediately if you or someone you know is showing signs of suicidal ideation

Suicide Risk

SSRIs may increase the risk of suicide in a small percentage of people. This is especially true for children and young adults under age 25. It’s not entirely clear whether the SSRIs cause this increased risk or if it is a result of worsening depression on its own. ^{[1] [2] [6]}

Regardless, it’s essential to watch out for warning signs if you or your child is taking an SSRI. Key warning signs to look out for include:

• Severe mood swings

• Antisocial behavior

• Aggression and irritability

• Thoughts of harming oneself

• Talking about wanting to die or feeling like a burden to others

• Shame and guilt

• Significant changes in eating and sleeping habits

• Engaging in risky behaviors

Getting a Prescription for SSRIs

SSRIs are prescribed as a first-line treatment for individuals dealing with moderate to severe symptoms of depression and/or other mental health concerns.

If you’re looking to get a prescription for an SSRI, you’ll have to meet with your primary care doctor. They will conduct a physical exam, go over your medical history, and listen to your symptoms and concerns. Sometimes, referral to a psychiatrist is needed.

Ultimately, whether or not you are prescribed an SSRI depends on the risk-to-benefit ratio. If there are no contraindications, and your symptoms are moderate to severe, they will likely prescribe an SSRI.

When to Seek a Diagnosis for Depression

You should seek a diagnosis for depression if you’re having significant symptoms that negatively interfere with daily life and your overall well-being. Common symptoms that warrant attention include:

• Feeling very down, empty, or hopeless.

• Decreased pleasure or interest in activities.

• Significant weight or appetite changes.

• Trouble sleeping or sleeping too much.

• Agitation.

• Loss of energy.

• Shame, guilt, or self-criticism.

• Suicidal ideation.

SSRI Treatment Plan

The exact treatment plan varies from person to person. Your doctor will present a treatment plan that is unique to your symptoms, goals, and individual characteristics.

Typically, there is a trial period of 4 to 8 weeks to see how you respond to the medication and dose. A low dose is usually used for this period. ^{[2] [5]}

Within this trial period, your doctor will recommend a follow-up after 2 weeks, sometimes just 1 week for younger individuals and others with a higher risk of suicidal ideation. ^[5]

After the trial period, your doctor will evaluate your treatment response and if any changes are needed. Sometimes, the dose may need to be increased. Other times, a change of medications is needed. Openly discussing all relevant information with your doctor is crucial to find the best treatment plan.

How Long Does it Last?

It is recommended that most individuals take SSRIs for at least 6 months after they begin to feel better. This is designed to provide a longer-lasting effect and help prevent the return of symptoms. Some individuals are on SSRIs for 6 to 12 months, while others with chronic depression may be prescribed SSRIs indefinitely. ^{[3] [5]}

Safely Stopping SSRI Treatment

After a sustained period of improved symptoms, you may be able to stop your antidepressant. However, this is a gradual process and needs to be done under medical supervision. Stopping your SSRI too quickly may lead to withdrawal or discontinuation syndrome, which can lead to several side effects, such as: ^{[2] [3] [5]}

• Restlessness

• Agitation

• Insomnia

• Aches and pains

• Suicidal ideation

• Mood changes

Rather than simply stopping SSRIs, your doctor will provide a tapering schedule, which gradually lowers the amount of medication you’re taking over time. Typically, the dose is reduced by a set percentage (e.g., 25%) every 2 to 4 weeks, although the exact protocol differs from person to person due to various factors (e.g., specific medication, length of treatment). ^{[5] [6]}

Final Thoughts

SSRIs have the potential to help with depression and several other mental health conditions. If you’re having symptoms of depression, anxiety, and/or other mental health concerns, SSRIs may be able to help. Talk with your doctor to learn what treatment plan is best for you.