SSRIs or SNRIs: Is One Type of Antidepressant Better?

SSRIs may be the most prescribed antidepressant, but does that mean they’re somehow better than SNRIs ― another type of medication used to treat depression and other mental health conditions?

The two antidepressants work in similar ways after all, and treat some of the same mood disorders. It makes you wonder how the medications differ aside from one letter in their well-known acronyms.

Let’s break it down with psychiatric pharmacist Josh Maline, PharmD, BCPP.

SSRIs vs. SNRIs

Both SSRIs (selective serotonin reuptake inhibitors) and SNRIs (serotonin and norepinephrine reuptake inhibitors) regulate emotions by influencing chemical messengers in your brain known as neurotransmitters.

“By balancing these chemicals, they can help improve symptoms of depression and anxiety and maybe reduce feelings of hopelessness that someone may have,” says Dr. Maline.

But the medications take different routes to reach the same goal.

Differences in how SSRIs and SNRIs work

SSRIs increase your brain’s levels of serotonin, often called your body’s natural “feel good” chemical. The medication does this by blocking the reuptake (or absorption) of serotonin by nerve cells in your brain.

“That allows more serotonin to stay active in your brain, which helps improve mood and reduce feelings of anxiety or depression,” explains Dr. Maline.

But serotonin isn’t the only chemical in your brain, which brings us to how SNRIs work.

“SNRIs are very similar to SSRIs, but they affect two chemicals in the brain instead of just one,” clarifies Dr. Maline.

Like SSRIs, SNRIs increase serotonin levels by blocking reuptake. But SNRIs also boost levels of a second chemical, norepinephrine, to improve mood while also increasing energy and alertness.

Norepinephrine plays a role in your body’s “fight-or-flight” response to danger, too. It’s naturally released from your adrenal glands during stressful moments to jolt your body and senses into action.

Common antidepressants

SSRIs and SNRIs are both routinely prescribed to treat mood disorders. You’ll probably recognize some of the medications and brand names that fall under both classes of antidepressants.

Examples of SSRIs include fluoxetine (Prozac®), citalopram (Celexa®) and Sertraline (Zoloft®). SNRI medications include duloxetine (Cymbalta®) and venlafaxine (Effexor®).

Potential side effects of SSRIs and SNRIs

Any medication comes with potential side effects. Different people respond differently to certain medications, too. But overall, SSRIs and SNRIs can both commonly lead to issues such as:

• Nausea
• Difficulty sleeping
• Headache
• Dry mouth
• Dizziness

More serious concerns include a risk of suicidal thoughts or behavior.

SNRIs may sometimes worsen symptoms of anxiety, given the increase in norepinephrine. “We do need to be a bit more cautious with SNRIs because of that potential for a ‘fight or flight’ response,” Dr. Maline reports.

But in general, both SSRIs and SNRIs are pretty well tolerated.

So, which is more effective?

When it comes to SSRIs versus SNRIs, one isn’t necessarily better than the other at treating depression or other issues. What works best for you depends upon … well, YOU and your needs.

“Both are first-line options for treating depression and anxiety,” says Dr. Maline, “but one might be a better option for you than the other based on your brain chemistry, as well as symptoms that you may be experiencing.”

It’s not unusual for someone to try a few prescriptions before finding what works best to treat issues like depression, anxiety, obsessive-compulsive disorder (OCD) or post-traumatic stress disorder (PTSD).

That could mean different versions of SSRIs or SNRIs, dosage adjustments or switching from one type of medication to the other, notes Dr. Maline.

Sometimes, doctors may even prescribe an SSRI or SNRI with another type of antidepressant, such as an NDRI (norepinephrine and dopamine reuptake inhibitors) to try to find the right combination.

And it may take a few weeks to two months to determine whether medications are working.

“Treatment is very individualized,” states Dr. Maline. “Two people can take the same antidepressant and have very different responses — not just from an efficacy standpoint, but in side effects, too. It can make finding the right medication very challenging.”

Dr. Maline also emphasized the importance of not relying solely on medications.

“Try to take a holistic approach, too,” he recommends. “Combing medications with therapy; getting adequate sleep and exercise; healthy eating; and stress management techniques have led to better outcomes for people.”