Mental Health
What Is The Difference Between SSRIs And SNRIs?

What Is The Difference Between SSRIs And SNRIs?

6 min read

·

Caitlin Harper

For people struggling with depression, antidepressants can sometimes be prescribed to help manage their symptoms.

Not all depression requires treatment with medication, but if you and your doctor decide that medication might be a good option for you, SSRIs, SNRIs, or a combination could be used.

SSRIs, or selective serotonin reuptake inhibitors, and SNRIs, or serotonin and norepinephrine reuptake inhibitors, are two different types of antidepressants. SSRIs work by increasing the level of serotonin in the brain, while SNRIs increase both serotonin and norepinephrine levels.

It can be hard to understand how different antidepressants work and which is the best fit for you. While your best resource is your doctor or psychiatrist, it never hurts to do some homework beforehand. This knowledge helps you have a better idea of what might be available so you can make the best decision for your care.

How Do SNRIs and SSRIs Work?

Serotonin reuptake inhibitors SSRIs, along with SNRIs, NRIs, NDRIs, and SNDRIs, are all reuptake inhibitors. They block the reuptake or reabsorption of your neurotransmitters, which are the body's chemical messengers.

These molecules are used by the nervous system to transmit messages between neurons, or from neurons to muscles. Neurotransmitters are involved in countless functions of the nervous system. They work to keep our brains functioning and control bodily functions like breathing. They also control psychological functions like joy and fear.

If your levels of neurotransmitters are already low, reuptake can reduce the amount of neurotransmitters in the brain. By blocking the reuptake of neurotransmitters and keeping their levels high, reuptake inhibitors increase the amount of neurotransmitters circulating or working at one time. This increased activity can have a positive effect on your mood.

There are three neurotransmitters that antidepressants can target to help regulate your mood: dopamine, norepinephrine, and serotonin. Each one plays a role in mood regulation and works a bit differently.

The Difference Between SSRI and SNRI Medications

While the aim of reuptake inhibitors is essentially the same, the difference between SSRI and SNRI medications lies in their slightly different approaches to achieving similar results.

What Are SSRIs?

An SSRI is any of a class of antidepressants that work by blocking the reuptake of serotonin into serotonin-containing nerve cells in the central nervous system. This action leads to increased serotonin levels in the brain.

Examples of SSRIs (with their brand names in parenthesis):

  • Citalopram (Celexa)
  • Escitalopram (Lexapro)
  • Fluoxetine (Prozac, Sarafem, Symbyax)
  • Fluvoxamine (Luvox, Luvox CR)
  • Paroxetine (Paxil, Paxil CR, Pexeva)
  • Sertraline (Zoloft)
  • Vilazodone (Viibryd)

What Are SNRI Drugs?

An SNRI is any of a class of antidepressants that exert their therapeutic effects by interfering with the reabsorption of both serotonin and norepinephrine by the neurons that released them.

Examples of SNRI drugs (with their brand names in parenthesis):

  • Duloxetine (Cymbalta)
  • Venlafaxine (Effexor, Effexor XR)
  • Levomilnacipran (Fetzima)
  • Desvenlafaxine (Pristiq, Khedezla)

Conditions These Medications Treat

In addition to depression, SSRIs are prescribed to treat mental health conditions like generalized anxiety disorder, obsessive compulsive disorder, panic disorder, and severe phobias such as agoraphobia and social phobia. They're also used for bulimia and post-traumatic stress disorder.

Sometimes SSRIs treat other conditions such as premature ejaculation, premenstrual syndrome, fibromyalgia, irritable bowel syndrome, and pain. SNRIs are also used to treat anxiety disorders and long-term (chronic) pain, especially nerve pain.

SSRIs vs SNRIs: Which One Is Better?

The short answer is: whatever you and your doctor decide is best for your specific situation!

Sometimes doctors prescribe a combination of SSRIs and SNRIs for their patients' treatment. Norepinephrine and dopamine reuptake inhibitors, or NDRIs, can be used as well.

SSRIs are more commonly prescribed because they can be more effective at mood regulation, sometimes with fewer side effects. SNRIs have the ability to improve energy levels, so each type has its own benefits. While a boost of energy might sound better, treating depression is about balancing the chemicals in your brain. Your doctor can determine what the best treatment choice and dosage is for you at a particular time.

Studies show that the benefit generally depends on the severity of the depression. The more severe the depression, the greater the benefits will be. In other words, antidepressants are effective against chronic, moderate and severe depression. They can be less effective in mild depression.

One of the largest issues with both SSRIs and SNRI medications is tolerance. Even if they help at first, any antidepressant may lose its effect after months or years. This happens because the brain has become less responsive to the drug. Solutions include increasing the dose and switching to another antidepressant with a different mechanism of action.

Common Side Effects of These Antidepressants

Common side effects of antidepressants may include:

  • Nausea and vomiting
  • Diarrhea or constipation
  • Weight gain
  • Headache
  • Drowsiness
  • Dizziness
  • Insomnia or sleep disturbances
  • Sexual dysfunction
  • High blood pressure (more common with SNRIs)

Side effects of SNRIs include some additional concerns. There may be an increased risk of high blood pressure and drug interactions compared to SSRIs.

Both medication types carry warnings from the Food and Drug Administration about a potential increase in suicidal thoughts, especially in young adults under 25.

It's important to discuss any side effects with your doctor. They may want to adjust your dosage or medication based on your experience.

How Long Will I Be on Antidepressants?

Antidepressants are usually taken daily. In the first few weeks and months, the goal is to relieve the symptoms. When possible, the aim is to make the depression go away completely.

It usually takes some time for your doctor to figure out the medication or combination that works best for you. It's hard, but be patient! Many antidepressants take a few weeks for you to notice any improvement in your symptoms.

After that, the treatment continues for at least four to nine months. The goal is preventing the symptoms from coming back. Sometimes, medication continues for longer to prevent relapses.

To discontinue use, most people need to gradually decrease their dose over time. Stopping immediately could cause withdrawal-like symptoms like dizziness, headaches, flu-like symptoms, and lethargy.

Some people take antidepressants for years. The duration of treatment varies from person to person. It depends on the severity of your depression, how your symptoms develop over time, and whether the depression returns or subsides.

Pairing Your Medication with Therapy Is Often More Effective

SSRIs and SNRIs are both prescription medications, so you must talk to a doctor to begin taking them. While antidepressants can treat the symptoms of depression or other conditions, they can't necessarily deal with everything.

They're often prescribed alongside therapy to help deal with the roots or causes of your symptoms. For depression, two kinds of psychotherapy have been shown to be helpful: cognitive-behavioral therapy and interpersonal psychotherapy.

There is evidence that combining psychotherapy and medications may be more effective than either treatment alone.

Looking for a therapist? Match with the right provider for you for free.

Finding the Right Treatment for You

There are many treatment options available for depression, anxiety, and other mood disorders. The SNRI vs SSRI decision should always be made with professional guidance.

Working with your doctor and therapist togehter will help figure out the best treatment for you. This collaborative approach ensures you get the care and support you deserve while managing any potential drug interactions or side effects effectively.

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About the author

Caitlin is an organizational change strategist, advisor, writer, and the founder of Commcoterie, a change management communication consultancy. She helps leaders and the consultants who work with them communicate change for long-lasting impact. Caitlin is a frequent speaker, workshop facilitator, panelist, and podcast guest on topics such as organizational change, internal communication strategy, DEIBA, leadership and learning, management and coaching, women in the workplace, mental health and wellness at work, and company culture. Find out more, including how to work with her, at www.commcoterie.com.

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