What Are Selective Serotonin Reuptake Inhibitors (SSRIs)? Everything You Need To Know

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If you or a loved one has been diagnosed with a mental health condition, you may have heard of selective serotonin reuptake inhibitors (SSRIs), a class of antidepressant medications commonly prescribed for the treatment of depression, anxiety disorders, and other mental health conditions. SSRIs increase serotonin levels in the brain, potentially decreasing depressive symptoms. With careful dosing and guidance from a primary care physician or psychiatrist, SSRIs may positively impact a person’s mental health, particularly when combined with therapy and certain lifestyle changes as directed by a healthcare professional.

For those who choose to take medication, finding the right type or dose may take time and patience. Below, we’ll discuss the basic features, science, and applications of selective serotonin reuptake inhibitors (SSRIs). Note that any medication, including SSRIs, should only be started, changed, or stopped under the direct guidance of a doctor like a psychiatrist.

What are SSRIs?

SSRIs are some of the most commonly prescribed antidepressants today. They are used to reduce the symptoms of depression and potentially prevent symptom relapses. Although selective serotonin reuptake inhibitors are a type of antidepressant medication, their uses extend beyond managing this condition. SSRIs may also be used to treat other mental health conditions like generalized anxiety disorder, obsessive-compulsive disorder (OCD), panic disorder, phobias, bulimia, post-traumatic stress disorder (PTSD), and premenstrual syndrome, in some cases. Antidepressants are often prescribed in combination with other treatment methods like therapy and lifestyle changes for maximum effect.

If you are experiencing trauma, support is available. Please see our Get Help Now page for more resources.

How do SSRIs work? 

To understand how selective serotonin reuptake inhibitors can help with depression and other conditions, it can be useful to familiarize yourself with some basic information on how serotonin and other neurotransmitters work. Fundamentally, SSRIs work by increasing levels of available serotonin, a neurotransmitter or chemical “messenger” that carries signals between nerve cells in the brain. Scientists believe that serotonin can have a positive influence on mood, emotions, and sleep.

After carrying a chemical message in the brain, serotonin is often reabsorbed by nerve cells. However, when SSRIs are present, they block or inhibit this “reuptake” of serotonin, which increases its availability in the brain. Over time, selective serotonin reuptake inhibitors can increase and stabilize levels of serotonin, which often correlates with improvements in depression symptoms. Some elements of the precise connection between serotonin levels, depression, and other mental health conditions remain unclear, however, and scientists continue to work to understand the full picture. 

How often do SSRIs need to be taken?

How often you take an SSRI depends on the type of SSRI you are prescribed and your unique treatment plan. You might be asked to take the medication for a few weeks before you notice any effects. Carefully follow your doctor’s medication instructions. Sticking to your self-care plan, continuing therapy, and reaching out to your doctor with any questions or concerns in the meantime may increase the likelihood of positive effects.

How long does it take for SSRIs to work? 

It may take two to four weeks of regular dosing before you notice any benefit from the treatment. The timeline can vary somewhat depending on which medication you are prescribed. When you first begin taking an SSRI, your doctor may prescribe a specific dosage—typically, the lowest possible dose—and monitor your response over the first few weeks. If you consistently take your medication as directed for four to six weeks with no noticeable benefits, check in with your doctor to see if a higher dose or alternative medication might be more appropriate or whether you want to add other elements to your treatment plan. 

When you find an SSRI that works well for you, your doctor may recommend taking it for at least six months after you notice an improvement in symptoms to prevent symptoms from worsening. For more severe depression or other conditions, your doctor may recommend you follow a longer course of medication or take SSRIs indefinitely. These are common recommendations; depending on your symptoms, however, your doctor may suggest you take selective serotonin reuptake inhibitors for more or less time.

What happens if you stop taking SSRIs?

If you’ve been taking selective serotonin reuptake inhibitors or SSRIs for several weeks, months, or years, suddenly stopping your medication routine can lead to withdrawal-like symptoms known as antidepressant discontinuation syndrome. These symptoms can include the following:

• Anxiety
• Dizziness
• Flu-like symptoms
• Shock-like sensations
• Stomach pain
• Seizures

If you’re considering going off antidepressants after an extended period of time, your doctor may recommend you taper off slowly and ultimately stop taking the medication. However, each person is different. Do not take any action without consulting your doctor. You could experience increased adverse health effects if you stop taking this type of medication abruptly. 

What are the side effects of SSRIs? 

As a commonly prescribed type of antidepressant treatment, research suggests that SSRIs are generally safe, effective, and well tolerated, meaning they don’t typically cause long-term side effects. However, side effects are possible and may occur for some people.

During the first few weeks after starting an SSRI, some individuals may experience short-term nausea, changes in appetite, and changes in sleep, which typically disappear after the body adjusts to the medication. Fewer side effects are reported later in treatment, though they may occur, including these:

• Sexual dysfunction, including erectile dysfunction, delayed orgasm, ejaculatory disorders, and reduced sex drive
• Headaches
• Sleep-related concerns, including insomnia, drowsiness, and vivid dreaming
• Diarrhea, indigestion, and constipation
• Agitation, shakiness, and/or anxiety
• Excessive sweating
• Overall feelings of sickness

Another of the potential side effects of SSRIs is an increased risk of suicidal thoughts in some individuals, particularly young adults. It’s important to notify your doctor if this occurs so they can adjust your or your child’s medication accordingly. 

If you or someone you know is experiencing suicidal thoughts or behaviors, seek help immediately. The National Suicide Prevention Lifeline can be reached 24/7 by dialing 988.

Less common side effects of SSRIs

In rare cases, people may experience more serious side effects as a result of taking SSRIs that require immediate medical attention. Uncommon and potentially serious effects of selective serotonin reuptake inhibitors can include these:

• Increased bruising 
• Vomiting with blood
• Confusion
• Stiffness, shaking, and other movement problems
• Hallucinations
• Inability to urinate
• Serotonin syndrome, which happens when serotonin levels are too high to the point that there’s more available than your body can use, with symptoms including confusion, agitation, muscle twitches, and diarrhea

If you experience any of these symptoms while using selective serotonin reuptake inhibitors, seek medical help immediately. 

In addition to the above potential side effects, individuals who take over-the-counter painkillers like nonsteroidal anti-inflammatory medications (NSAIDs) also are at a significantly increased risk of gastrointestinal bleeding. A psychiatrist may ask about your current use of over-the-counter medications before prescribing an SSRI. Bring a list of your medications with you to your doctor before starting a new medication. 

For people with certain underlying health problems such as diabetes, epilepsy, or kidney disease, using SSRIs may not be recommended. SSRIs also may not react favorably with common herbal remedies like St. John’s Wort. Ultimately, every person’s body and circumstances are different, and you should work closely with a physician to help you feel informed and safe while taking selective serotonin reuptake inhibitors.

Therapy may enhance the effectiveness of SSRIs

As you adjust to the effects of selective serotonin reuptake inhibitors or SSRIs, talk therapy may help you manage your symptoms and give you coping mechanisms so you can manage your illness over time. SSRIs and other antidepressants are often prescribed in conjunction with therapy, which can represent an opportunity to reflect on personal challenges that may be influencing your mental health and improve related mental health conditions.

Some people prefer traditional in-person therapy to facilitate these conversations. However, if you’re balancing a busy schedule, family life, and/or other obligations, you may prefer online therapy as a more convenient way to supplement your SSRIs or other medication. Online therapy platforms like BetterHelp make it easy to connect with a licensed provider. After completing a brief questionnaire, you’ll be matched with a therapist in as little as 48 hours. From there, you can connect with your therapist via phone or video chat, and you can contact them with any concerns in between sessions via in-app messaging.

Various studies in recent years have suggested that online therapy can be just as effective in treating various mental health conditions as in-person sessions, whether you engage in therapy alone or in combination with medication. For example, consider a study from 2020 that demonstrates the efficacy of digital cognitive-behavioral therapy (CBT) for people experiencing depression and anxiety.