Selective Serotonin Reuptake Inhibitors[SSRIs]: Types, Uses, Drug, Side Effects, and How it Works

May 22, 20248 min
Girl with medicine like SSRIs with happy face

What Are SSRIs?

Selective Serotonin Reuptake Inhibitors (SSRIs), classified as anti-depressants, are medicines that interact within the brain and are prescribed to individuals to alleviate symptoms of depression and anxiety. Though not conclusive, the consensus since the 1950s is that serotonin plays a key role in depression. Thus, the major aim of SSRIs is to increase serotonin levels in the brain. 

While it may help some people, it may not help others depending on a myriad of factors including the nature of the depressive disorder. We are not certain of what causes depression, but we know there is a mix of biological, psychological, and social elements interacting with each other in the bag.

Girl with medicine like SSRIs with happy face

Types of Selective Serotonin Reuptake Inhibitors [SSRI]

We still talk about brain health as if the person always has control over the workings of its structures. However, when we talk about clinical depression, it’s essential to understand it isn't anyone’s fault; but rather learning to live with and manage a mental health condition. SSRIs are one of the ways to go about it. 

While the most common use of SSRIs is to manage Major Depressive Disorders (MDDs), Psychiatrists have often prescribed them to treat:

Sometimes, SSRIs are used off-label to support other conditions which it is not specifically designed to treat, including:

  • Fibromyalgia
  • Binge eating disorder
  • Body dysmorphic disorder
  • Autism

Some commonly known anti-depressants with their brand names are mentioned below:

  • Fluoxetine (Prozac)
  • Sertraline (Zoloft)
  • Escitalopram (Lexapro)
  • Paroxetine (Paxil)
  • Citalopram (Celexa)
  • Fluvoxamine (Luvox)

Medication like SSRIs, can be an effective way of managing clinical depression when combined with other forms of treatment and support. The right support and care go a long way to live a fulfilling life.

How do SSRIs really work?

SSRIs interact with serotonin to work. Serotonin is a neurotransmitter, i.e., a messenger in the body, carrying critical messages that affect your mental health.  

To explain briefly, imagine you are expecting an important delivery of packages to your home. The delivery person represents serotonin, a messenger in your brain that affects your mood. They have many packages to deliver to you. 

However, the delivery person's manager (the serotonin transporter) tells them to only deliver some of the packages and leave the rest. 

As a result, you don't receive all the packages (serotonin) you were expecting. You only get a portion of the delivery.

Just like not receiving all your expected packages can be disappointing, not having enough serotonin in your brain can lead to low moods and anxiety.

SSRIs work like an external inspector who blocks the manager (serotonin transporter) from reabsorbing serotonin (packages) from your brain. This allows more serotonin to be available, improving your mood.

A brain with pink pills which trying to show how SSRIs works

Benefits and Side Effects of SSRIs 

SSRIs are usually taken orally in tablet form. Your psychiatrist usually prescribes a dosage based on your presenting symptoms and their severity. There are continuous check-ins and monitoring of your symptoms using SSRIs to see if they’re helping.

As you continue their use, you will come across some benefits:

Benefits of SSRIs:

  1. Antidepressants like SSRIs have been found to improve symptoms in treating major depression. 
  2. SSRIs are proven to be generally safe in testing and clinical trials, i.e., they are associated with fewer adverse effects compared to other kinds of anti-depressants. 
  3. SSRIs may often help with low moods, lethargy, and apathy experienced in depression 
  4. Improved symptoms allow for increased energy and allow one to focus on other parts of your care plan like therapy, self-care tasks, and everyday activities.
  5. People on anti-depressants report they have an improved quality of life. 

However, anti-depressants work differently for different people. It is important to review how an antidepressant is working out for you and adjust the dosage as necessary under the guidance of your psychiatrist.

Side Effects of SSRIs:

  1. You may experience some physical symptoms like changes in weight, anxiety, dizziness or headaches, and gastrointestinal discomfort. 
  2. Anti-depressants may or may not help with the sleep disturbances caused by the depressive symptoms. Sometimes, you may experience insomnia or be too sleepy as well as side effects of using ant-depressants. 
  3. A less talked about side effect in adults is sexual dysfunction with the use of SSRIs. So, if you ask, What is post-SSRI sexual dysfunction, some signs include delayed or blocked orgasm, trouble maintaining an erection, and delayed lubrication.  
  4. For children and young adults up to age 25 experiencing depression and suicidality, SSRIs can be more risky than beneficial. 
  5. Although not as common, some SSRIs like citalopram and escitalopram are associated with a risk of abnormal heart rhythm that can lead to complications in heart health.
  6. Serotonin syndrome is an uncommon but serious side effect. It is as its name suggests when serotonin in the brain becomes too high and leaves you:
  • Confused
  • Agitated
  • Sweaty
  • Shivering
  • Diarrhoeal

Risks or Complications of SSRIs

While SSRIs come with their benefits, it is wise to ask your healthcare provider if they can work for you specifically. Having certain medical conditions and interaction with other medications can put you at risk of some of the side effects and other adverse symptoms. 

If you’re dealing with any of the following, be sure to let your doctor know during your consultation:

  • Epilepsy 
  • Diabetes
  • Heart conditions
  • Medications for any other health conditions
  • Comorbid mental health conditions
Brain xray along with expert

SSRIs, pregnancy, and post-natal care 

Pregnancy is a time when there are many physical and hormonal changes experienced by a woman and it is easy to lose focus on the mental health of the to-be mother especially since many concerns can be seen as a normal part of pregnancy. However, women with a history of anxiety or depression may be more at risk for depression when pregnant. 

  1. The changes you experience can also impact your medication if you are already on any anti-depressant. 
  2. There are mixed results on anti-depressant use during pregnancy and related birth defects. However, it is generally assumed to be safe. 
  3. It may be a good idea to explore the risks with your doctor and make changes to your dose and usage as per your collaborative consultation.
  4. It is not advisable to discontinue anti-depressants on your own as it can lead to the risk of relapse of depressive symptoms. 

SSRIs vs SNRIs: Difference Between



Full form 

Selective Serotonin Reuptake Inhibitors

Serotonin - Norepinephrine Reuptake Inhibitors  

Neurotransmitters at play

  • Serotonin

  • Serotonin

  • Norepinephrine

How do they work?

Blocks reabsorption of serotonin, making it more available 

Block reabsorption of both serotonin and norepinephrine, making both more available 

What are the SSRI withdrawal phases?

One important thing to keep in mind about SSRIs is that since they cause changes in brain chemistry, there is a risk of the benefits being reversed if someone stops taking them abruptly. SSRI withdrawal phase can begin within 2 to 4 days of stopping the medication provided a minimum use of 4 weeks. 

1. Changes in the brain chemistry: 

Since SSRIs allow for more volume of serotonin in the brain, the brain regulates itself by reducing the number of receptors than before. So, when you stop taking SSRIs it takes some time for the brain to correct this change.

2. Clearing the bloodstream: 

Different SSRIs have different thresholds of clearing from your bloodstream. You may experience gradual or abrupt withdrawal symptoms if you discontinue your medications abruptly. 

3. Tapering it with an expert: 

It's crucial to taper off SSRIs gradually under a doctor's guidance, rather than just stopping cold turkey. Going the gradual route minimizes the chances of withdrawal symptoms popping up or a resurgence of the original symptoms.

Withdrawal Symptoms 

When it comes to abruptly stopping an antidepressant an SSRI, there's a handy mnemonic that covers the potential withdrawal effects - FINISH. 

Let's break it down:

F - Flu-like symptoms (feeling lethargy, fatigue, achy headaches, and sweating like you have the flu) 

I - Insomnia (difficulty sleeping, coupled with some vivid dreams or nightmares)

N - Nausea (feeling queasy and possibly even throwing up) 

I - Imbalance (the world spinning with dizziness, vertigo, and light-headedness) 

S - Sensory disturbances (weird "burning," "tingling," "electric" or "shock-like" sensations) 

H - Hyperarousal (amped-up anxiety, irritability, agitation, aggression, mania-like symptoms, and overall jerkiness)


Can I drink alcohol while on an SSRI?

It is usually ill-advised to drink alcohol with an SSRI. Alcohol acts on the brain as a depressant, affecting serotonin levels.  

Why do SSRIs cause weight gain?

Although SSRIs are known to cause weight gain, scientists don't have an exact answer to why. Some speculate that weight gain after using SSRIs can be seen as a positive sign that SSRIs are working if the symptoms before were excessive weight loss or a residual of the depressive symptoms

However, it is also important to check for other factors that may be causing the weight gain (for example, medical concerns a sedentary lifestyle, or an inadequate diet). It is best to make these judgments with your healthcare provider.  

Do SSRIs reduce fear?

Yes, SSRIs can reduce fear. Many people with mental health concerns are prone to have an inaccurate perception of reality due to overwhelm. Taking SSRIs can provide relief from such symptoms, creating mental space to work on the thoughts, feelings, and behaviors that may be causing distress. This results in the reduction of fear. 


SSRIs like Fluoxetine (Prozac) and Sertraline (Zoloft) are considered safe medical treatments for concerns such as depression and anxiety. These medications work by increasing the availability of serotonin in the brain, which is associated with improved moods in patients with anxiety and depression. 

There are many benefits to using psychopharmacological treatments for such concerns under the supervision and guidance of a trusted psychiatrist. However, there are some concerns to be aware of, such as side effects that can be difficult to manage or potential interactions with other medical conditions or medications.

When starting an SSRI, it is crucial to monitor its use and not stop it abruptly. Abruptly discontinuing an SSRI can lead to withdrawal symptoms that can be challenging to navigate alone. 

These medications cause changes in brain chemistry, and an abrupt cessation can disrupt the delicate neurochemical balance achieved during treatment. Therefore, it is essential to work closely with a healthcare professional to gradually taper off the medication if discontinuation is necessary. 

This approach minimizes the risk of experiencing a reversal of benefits or withdrawal effects, ensuring a smooth transition and preserving the therapeutic gains obtained during the course of treatment.


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Clinical Psychologist