SSRIs: Everything You Need To Know

Medically Reviewed by Jabeen Begum, MD on February 01, 2024
Written by Tammy Worth
9 min read

Selective serotonin reuptake inhibitors (SSRIs) are antidepressant medications used to treat depression, anxiety, panic disorder, and several other mental health conditions. SSRIs are the most commonly prescribed antidepressants. They are considered relatively safe and cause fewer side effects than other kinds of medications used to treat depression. About 13% of U.S. adults take antidepressants, with rates of use higher among women and people over the age of 60.

SSRIs work by enhancing the function of nerve cells in the brain that regulate emotion. Information is communicated between your brain cells through signals. The chemical messengers that deliver these signals are called neurotransmitters. Serotonin is one type of neurotransmitter.

When these brain cells (called neurons) send signals to one another, they release a little bit of a neurotransmitter so the message can be delivered, and then take back the neurotransmitter to send the next message. This process of replacing the neurotransmitter is called “reuptake.”

If you’re struggling with depression, the areas of your brain that regulate mood and send messages using serotonin might not function properly. SSRIs help make more serotonin available by blocking the reuptake process. This allows serotonin to build up between neurons so messages can be sent correctly. They’re called selective serotonin reuptake inhibitors because they specifically target serotonin.

The U.S. FDA has approved SSRIs to treat the following conditions:

  • Major depressive disorder
  • Generalized anxiety disorder
  • Panic disorder
  • Obsessive-compulsive disorder (OCD)
  • Social anxiety disorder
  • Posttraumatic stress disorder (PTSD)
  • Premenstrual dysphoric disorder (PMDD)
  • Bipolar depression
  • Bulimia nervosa
  • Treatment-resistant depression

Your doctor may also prescribe an SSRI for other conditions, not approved by the FDA. This is called off-label use. These conditions include:

  • Body dysmorphic disorder
  • Fibromyalgia
  • Premature ejaculation
  • Binge eating disorder
  • Raynaud's phenomenon
  • Autism
  • Menopausal hot flashes

The FDA is in charge of deciding which medications are safe and effective for which conditions. The following SSRI drugs are approved to treat depression. Some of these are used more often for other conditions such as anxiety, OCD, binge eating disorder, and other mood disorders. SSRIs are only available orally and given in the form of tablets, capsules, or liquids. FDA-approved SSRIs are:

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

SSRIs have been linked to thoughts of suicide in children and young adults, and not all are available for people in this age group. The SSRIs approved by the FDA for treating children and adults under age 25 include escitalopram, fluoxetine, fluvoxamine, and sertraline.

Most people who use SSRI drugs don’t get major side effects, but every kind of medical treatment carries some risk. The possible side effects of these antidepressants include:

  • Insomnia
  • Headaches
  • Rash
  • Blurred vision
  • Drowsiness
  • Dry mouth
  • Agitation or nervousness
  • Dizziness
  • Pain in the joints or muscles
  • Upset stomach, nausea, or diarrhea
  • Reduced sexual desire
  • Problems with erection or ejaculation
  • Weight loss or weight gain

Some of the possible side effects can be helped by adjusting the timing of your medication. If you have nausea, it might help to take an SSRI with food or before you go to sleep. If you have insomnia, you can try taking the medicine in the morning. And if it causes drowsiness, take it at night. If you are having sexual side effects, you can try taking it once a day and wait until after sex.

Some people, especially children and young adults (up to age 25), may be more likely to have suicidal thoughts when they take SSRIs. Studies show that when compared to results from taking a placebo, chances of having suicidal thoughts doubled (from 1%-2% to 2%-4%) when taking any kind of antidepressant, including an SSRI. If you have thoughts of hurting yourself while taking an SSRI, call 911.

There are also important safety issues to consider about SSRIs.

SSRIs can have dangerous interactions with some medicines, both prescription and over-the-counter, including herbs and supplements. Before starting an SSRI medication, make sure to tell your doctor all the different kinds of medications and supplements you're taking.

As all SSRIs work in a similar way, their side effects tend to be similar, too. But each SSRI has a different chemical makeup, so it’s possible that if you’re having side effects from one, you may not have as many, or any at all, if you switch to another.

Although it’s rare, if too much serotonin accumulates in your system, you can develop a condition called serotonin syndrome. This can happen when you start taking a new SSRI or switch to a different one. It is most common when you are taking two different medications that increase serotonin. This may involve, for example, two SSRIs or an SSRI and a Monoamine oxidase inhibitor (MAOI), which are used to treat conditions such as Parkinson's disease and depression with atypical symptoms (like overeating). Symptoms of serotonin syndrome include: 

  • Nervousness
  • Stomach issues such as nausea, vomiting, and diarrhea
  • Sweating
  • Shivering
  • Eye movement from side to side
  • Dilated pupils
  • Muscle twitching, contractions, and spasms
  • Confusion
  • High blood pressure
  • Fever
  • Seizures
  • Loss of consciousness

If you are experiencing symptoms of serotonin syndrome, call your doctor immediately. If the condition is severe and you don't get treated, it can be fatal.

While some people have side effects from taking SSRIs, others do not. In many cases, the side effects disappear after a few weeks of treatment. It’s important to work with your doctor to find the SSRI medication that’s right for you.

As many as 20% of women and people assigned female at birth (AFAB) have depression during or after pregnancy. About 5%-7% of people with depression are treated with antidepressants at some point during pregnancy. There is some stigma associated with taking antidepressants during pregnancy, but only you and your doctor can know what is right for you.

Depression during pregnancy can impact both you and your baby. If left untreated, depression can increase the risk of health complications for you including:

  • Preeclampsia
  • Increased risk of suicide
  • Greater risk of postpartum depression
  • Difficulty bonding with the baby after birth

If your depression is left untreated during pregnancy, it puts your baby at higher risk of having several health conditions, such as:

  • Premature birth
  • Low birth weight
  • Irritability after birth
  • Increased levels of noradrenaline and cortisol (fight-or-flight and stress hormones)
  • Decreased levels of serotonin and dopamine (hormones associated with good moods and emotions)
  • Other cognitive and emotional problems after birth

Your doctor may prescribe SSRIs such as citalopram, escitalopram, sertraline, and fluoxetine during your pregnancy. However, there are several potential risks to the baby associated with taking SSRIs during pregnancy. They include:

  • Irritability
  • Jitters
  • Poor feeding habits
  • Breathing difficulties
  • Premature birth
  • Increased risk of stillbirth
  • Increased risk of spontaneous abortion

Taking antidepressants during the third trimester of pregnancy may also increase the risk of things such as lower Apgar scores (a scoring system that checks the health of the infant within minutes of birth), restlessness, low blood sugar, vomiting, temperature instability, nervousness, and tremor. These symptoms may be caused by the medication itself, or they may be a result of the baby going through withdrawal from the antidepressant.

If you have depression and are pregnant or planning to get pregnant, you should talk to your doctor about the risks and benefits of taking SSRIs during this time.

SSRIs and breastfeeding

Antidepressants are usually considered safe to use while breastfeeding. Major health conditions for the newborn aren't likely when the breastfeeding person takes antidepressants, but there have been reports of babies having:

  • Irritability
  • Feeding problems
  • Sleep issues
  • Jitters
  • Excessive crying

Serotonin and norepinephrine reuptake inhibitors (SNRIs) are other commonly prescribed antidepressants that work similarly to SSRIs, changing brain chemistry to affect your mood. SNRIs block the reuptake of both serotonin and norepinephrine, another neurotransmitter (chemical messenger). Serotonin is thought to impact your appetite, sexual desire, and social interactions, while norepinephrine affects how alert you are, how you pay attention, and your sexual arousal. 

SNRIs that are FDA-approved are:

  • Desvenlafaxine (Khedezla, Pristiq)
  • Duloxetine (Drizalma, Irenka, Cymbalta)
  • Levomilnacipram (Fetzima)
  • Milnacipran (Savella)
  • Venlafaxine (Effexor)

Different SNRIs are used for different conditions, but most are used to treat major depressive disorder. Other uses for SNRIs include:

  • Fibromyalgia: Milnacipran, Duloxetine
  • Generalized anxiety disorder: Duloxetine, Venlafaxine
  • Pain related to diabetic neuropathy and chronic musculoskeletal issues: Duloxetine
  • Social anxiety and panic disorder: Vanlafaxine

Your doctor may also prescribe SNRIs for off-label use (not approved by the FDA) for conditions such as: 

  • Menopause-related night sweats and hot flashes
  • Urinary Incontinence
  • Neuropathy from chemotherapy
  • OCD
  • Migraines
  • Attention deficit hyperactivity disorder 

Everyone responds differently to SSRIs in terms of seeing improvements. People typically start noticing positive changes after about 4-6 weeks of treatment. It can take several months to feel the full effect of the medication. If you’re not feeling any improvements after about 6-8 weeks, talk to your doctor about trying another treatment or adjusting your dosage. About 9% of people taking SSRIs switch from one medication to another within the first 2 months of treatment.

Choosing an SSRI

It may take some time to find the SSRI that works best for you. You and your doctor can discuss your symptoms, side effects, and other issues when figuring out which one to take. Some things to consider include:

  • Your symptoms: Some SSRIs work better for different symptoms, such as sleeplessness or anxiety. 
  • Side effects: SSRIs vary in their risk of causing side effects such as weight gain, sexual dysfunction, and nausea. 
  • Genetics: If a close family member had a good result from an SSRI, the odds are good that you may, too.
  • Drug interactions: Some SSRIs interact with other medications; make sure your doctor knows any other drugs or supplements you are taking before you begin a new SSRI.
  • Cost: Some SSRIs can be expensive, so talk with your doctor about what your insurance covers and if generic medications are available.

Helping SSRIs work

There are some things you can do to make SSRIs work better for you. First, you must have patience. It may take time for an SSRI to work. Your doctor may start you on a lower dose and increase it gradually to the full dose. Side effects you have when you start an SSRI medication may also fade after a few weeks.

Also, you should take your SSRI regularly, without skipping doses for the best results. Also, don't stop taking your SSRI drug without talking to your doctor first. Stopping suddenly can cause withdrawal symptoms or make your depression worse.

If you are taking an SSRI, you should avoid using alcohol and recreational drugs, which have been shown to worsen depression symptoms.

Even though SSRIs aren’t habit-forming, it can be dangerous to stop them suddenly or miss several doses in a row. Doing this can lead to a condition called discontinuation syndrome that causes withdrawal-like symptoms.

If you do have discontinuation syndrome, you might start to feel like you have the flu and/or notice symptoms such as:

  • Nausea
  • Dizziness
  • Uneasiness
  • Fatigue or lethargy

That’s why it’s important to work up to your prescribed dosage slowly with the help of your doctor and to step down gradually if you agree it’s time to stop.

Some people who take SSRIs may have sexual side effects such as loss of sex drive and weak orgasms. If you had these side effects, there is a small chance they will continue after you stop taking the SSRI. Sexual dysfunction after taking SSRIs can include symptoms such as:

  • Premature ejaculation
  • Weak orgasms or ones that provide no pleasure
  • Decreased sex drive
  • Erectile dysfunction
  • Numbness of the genitals

If you think you might be dealing with depression, anxiety, or another mental health condition, talk to your doctor to see if medication, such as an SSRI, might be helpful for you. Being patient with your treatment is an important part of taking SSRIs because they may take weeks to work and come with a range of potential side effects. You may need to try more than one SSRI to find what works best for you.

Can I drink alcohol when taking an SSRI? It's best to avoid alcohol and other recreational drugs when taking an SSRI. Alcohol is a depressant and can work against the medication to worsen your symptoms.

How do I know if I need an SSRI? SSRIs are used to treat major depressive disorder, anxiety, and other behavioral health conditions such as OCD. Chronic depression symptoms include a lack of interest in things you used to enjoy; too much or too little sleep; extreme lack of energy; and suicidal thoughts. Your doctor can diagnose major depressive disorder and prescribe an SSRI if they think it is right for you.