What Are SSRIs and How Can They Treat Depression?

Brain chemistry may contribute to anxiety disorders or depression. Therefore, taking antidepressant medications can help change brain chemistry for the better. Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants; they are relatively safe and cause fewer side effects compared to other types of antidepressants.

How Do SSRIs Work?

SSRIs treat symptoms of depression by increasing levels of serotonin in the brain. Serotonin is one of the chemical messengers, or neurotransmitters, that carry signals between brain nerve cells or neurons.

SSRIs block the reuptake of serotonin, which increases serotonin availability. This can improve the transmission of messages between neurons. SSRIs are called selective because they mainly affect serotonin.

Along with depression, SSRIs can be used to treat a number of other mental health conditions, including:

SSRIs can sometimes be used to treat other health problems such as premature ejaculation, premenstrual syndrome (PMS), fibromyalgia and irritable bowel syndrome (IBS). Occasionally, they may also be prescribed to treat pain.

SSRIs Approved to Treat Depression

The Food and Drug Administration (FDA) has approved these SSRIs to treat depression:

  • Citalopram (Celexa)
  • Escitalopram (Lexapro)
  • Fluoxetine (Prozac)
  • Paroxetine (Paxil, Pexeva)
  • Sertraline (Zoloft)


Like SSRIs, serotonin-norepinephrine reuptake inhibitors (SNRIs) keep the body from reabsorbing too much serotonin, allowing the brain to use more of it. However, unlike SSRIs, SNRIs also lessen the reuptake of the neurotransmitter norepinephrine. Some examples of SNRIs include:

  • Venlafaxine (Effexor XR)
  • Desvenlafaxine (Khedezla, Pristiq)
  • Duloxetine (Irenka, Cymbalta)
  • Milnacipran (Savella)

Based on your symptoms, you and your healthcare provider can decide whether an SNRI or SSRI is the best option for you.


Monoamine oxidase inhibitors (MAOIs) were the first type of antidepressant developed. They’re effective, but they’ve been replaced by antidepressants that are safer and cause fewer side effects, like SNRIs and SSRIs.

Possible Side Effects of SSRIs

Most if not all SSRIs work similarly and can cause similar side effects. Many side effects go away after the first few weeks of treatment, while others may lead you and your doctor to try a different drug. Some people don’t experience any side effects at all.

Common side effects of SSRIs may include:

  • Nausea, vomiting or diarrhea
  • Headaches
  • Drowsiness
  • Dry mouth
  • Insomnia
  • Nervousness, agitation or restlessness
  • Dizziness
  • Sexual problems, such as reduced sexual desire, difficulty reaching orgasm or inability to maintain an erection
  • Differences in appetite causing weight loss or gain

Ask your healthcare provider and pharmacist about the most common possible side effects of your prescribed SSRI.

How Long Do SSRIs Take to Work?

When SSRIs are prescribed, you’ll start on the lowest possible dose necessary to improve your symptoms. SSRIs typically need to be taken for 2 to 4 weeks before improvement is noticed. You may experience mild side effects early on, but it’s important that you continue taking the medication. These effects usually wear off quickly.

If you take an SSRI for 4 to 6 weeks without feeling any benefit, speak to your doctor or a mental health professional. They may recommend increasing your dose or trying a different antidepressant. A course of treatment usually lasts for at least 6 months, although sometimes longer courses are necessary.

Safety Concerns

SSRIs are generally safe for most people. However, in some circumstances, they can cause problems. Make sure to discuss these issues with your healthcare provider before taking an SSRI:

  • Drug interactions. When taking an antidepressant, tell your healthcare provider about any other medications, herbs or supplements you’re taking. Some antidepressants can interfere with the effectiveness of other medications, and some can cause dangerous reactions when combined with certain medications or herbal supplements.
  • Serotonin syndrome. Rarely, an antidepressant can cause high levels of serotonin to accumulate in your body. Serotonin syndrome most often occurs when two medications that raise the level of serotonin are combined. These include, for example, other antidepressants, certain pain or headache medications, and the herbal supplement St. John’s wort.
  • Antidepressants and pregnancy. Some antidepressants may harm your baby if you take them during pregnancy or while breastfeeding. If you’re on an antidepressant and considering getting pregnant, talk to your doctor about the possible risks.

Suicide Risk and Antidepressants

Most antidepressants are generally safe, but the FDA requires that all antidepressants carry black box warnings. In some cases, people under 25 years old may have an increase in suicidal thoughts or behavior when taking antidepressants, especially in the first few weeks after starting or when the dose is changed.

Anyone taking an antidepressant should be watched closely for worsening depression or unusual behavior. If you or someone you know has suicidal thoughts when taking an antidepressant, immediately contact your healthcare provider or seek emergency help.

The good news is, antidepressants are more likely to reduce suicide risk in the long run by improving mood.

Stopping Treatment With SSRIs

SSRIs aren’t addictive. However, stopping antidepressant treatment abruptly or missing several doses can cause withdrawal-like symptoms, sometimes called discontinuation syndrome. Work with your doctor to gradually and safely decrease your dose.

Withdrawal symptoms can include:

  • General feeling of uneasiness
  • Nausea
  • Dizziness
  • Lethargy
  • Flu-like symptoms

Making Antidepressants Work For You

It may take a few tries to find the right medication and dose for you, and that’s okay. To get the best results from an antidepressant:

  • Be patient. Every medication is different. Talk to your doctor or therapist about coping with depression symptoms as you wait for the antidepressant to take effect.
  • Take your antidepressant consistently and at the correct dose. If your medication doesn’t seem to be working or is causing bothersome side effects, talk to your doctor before making any changes.
  • See if the side effects improve. Unwanted antidepressant symptoms usually go away as your body adjusts to the medication. If they don’t, talk to your doctor about changing your dose or switching to a different medication altogether.
  • Try psychotherapy. In many cases, combining an antidepressant with talk therapy (psychotherapy) is more effective than taking an antidepressant alone. It can also help prevent your depression from returning once you’re feeling better.
  • Don’t stop taking an antidepressant without talking to your doctor first. Some antidepressants can cause significant withdrawal-like symptoms unless you slowly taper off your dose. Quitting suddenly may cause a sudden worsening of depression.

Avoid alcohol and recreational drugs. Alcohol and recreational drugs generally worsen depression symptoms.

We’re Here For You

When it comes to treating depression, at the Anxiety and Depression Institute, our providers use your input to create a treatment plan specific to you. We are here to help you overcome depression and live your best life. Schedule an appointment today by calling 248-791-9822 or filling out this form on our website.

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