Taking antidepressants: What should I know?

October 16, 2020
9 minute read

Antidepressants are a unique class of medicine that aren’t without side effects and cautions. As a result, many people can feel reluctant to take them. Starting treatment with antidepressants can be a big decision.  

In this article, we will cover the most common questions and aspects that you should be aware of when starting treatment with antidepressants.  

Why have I been prescribed antidepressants?

Antidepressants are medicines that are primarily intended to treat depression. Their use extends to other health conditions, such as anxiety disorders, phobias, obsessive compulsive disorder, and even neuropathic pain.

Antidepressants represent a viable treatment option for depression and are most often prescribed in cases where the severity of your depression is moderate or high and your illness interferes with your daily life.

In cases of mild depression, doctors recommend counselling or cognitive behavioural therapy first.

However, even in cases of moderate and severe depression, many doctors will recommend both antidepressants and therapy, as research suggests that combining both methods is the best approach to getting better.

I’ve been given an SSRIs – what is it?

There are many types of antidepressants, and they differ in their precise mechanism of action, side effects, cautions, efficacy, and indications.

The most commonly prescribed type of antidepressants is called Selective Serotonin Reuptake Inhibitors, or SSRIs. They represent the first-line treatment option in the UK and around the world and many doctors will start with an SSRI because their side effects are milder, and most people find them more tolerable.

Examples of SSRIs include sertraline, fluoxetine, citalopram, paroxetine and vortioxetine, among others.

Other types of antidepressants include Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs), Noradrenergic and specific serotonergic antidepressants (NaSSas), Tricyclic antidepressants (TCAs), Monoamine oxidase inhibitors (MAOIs) and Glutamatergic antidepressants.

Some types of antidepressants such as TCAs and MAOIs are older and only prescribed in rare cases, whereas other types such as SNRIs and NaSSas are newer types of antidepressants and prescribed in cases where patients do not respond to or tolerate SSRIs. Moreover, glutamatergic antidepressants are the newest class of antidepressants and include the drug ketamine. Ketamine can be administered intranasally or via infusion in cases of severe depression where patients do not respond to any other antidepressants.

Your doctor will explain which type of antidepressant is right for you.

Sertraline is one of the most prescribed antidepressant medications in the UK

How do antidepressants work to treat depression?

Depression is a complex illness, and doctors and researchers are not yet sure about the precise mechanism through which antidepressants work.

One of the original hypotheses’ states that antidepressants such as SSRIs and SNRIs work by increasing the amount of certain chemicals in the brain that are thought to be too low during depression. This idea, however, is largely regarded as an oversimplification.

Though scientific consensus has yet to be reached, researchers have proposed several, more complex mechanisms that may actually explain how types of antidepressants such as SSRIs and SNRIs work, such as hippocampal neurogenesis (a process where new neurons are created in the area of the brain known as the hippocampus).

Different types of antidepressants have different mechanisms of action.

How long does it take for antidepressants to work, and what are the side effects?

Most prescribed antidepressants take a few weeks (2-4 weeks) to work, during which time you will likely experience side effects. However, it’s important to keep taking your medication as prescribed.

Your doctor will likely want to see you soon after prescribing an antidepressant to see how you are getting on.

All antidepressants have side effects. For example, SSRIs may lower your sex drive, and can cause nausea or weight gain. Some people may even feel worse for a short while after starting to take antidepressants.

  • Nausea and vomiting
  • Insomnia
  • Agitation
  • Weight gain
  • Constipation
  • Anxiety

The side effects are temporary, will generally subside in a few weeks, and the antidepressants will start to work and help you feel better. Therefore, it’s important to keep taking them: don’t miss doses and keep in contact with your GP throughout this process.

Some people do not respond well to particular antidepressants, in which case your GP will help you find an alternative antidepressant.

How long do I need to take antidepressants for?

How long you take an antidepressant depends largely on your diagnosis. For people with diagnoses such as Major Depressive Disorder (MDD), which is an episodic disorder characterised by recurring depression, your doctor will generally advise you to take it for at least six months even after your symptoms go away, to help prevent the return of symptoms.

You will need to go back to see your GP regularly, who will advise you on the best course of action.

Can I simply stop taking antidepressants?

No – always talk to your GP before stopping antidepressants. Abruptly stopping antidepressants can cause discontinuation symptoms, such as insomnia and feelings of dizziness.

Anything else I need to be aware of?

There are several cautions associated with taking antidepressants. These include pregnancy and breastfeeding, potential interactions with other medicine, alcohol and illegal drugs, prescribing antidepressants for younger individuals and children, and combining antidepressants.

You should always speak to your GP or pharmacist if you have any cause of concern when taking an antidepressant.


You can call the Samaritans on 116 123 (UK and ROI)

Samaritans are a registered charity that provide emotional support and guidance to anyone who needs it. It’s free to call and someone will be able to talk to you.

The NHS also has a wealth of information on the topic which you can access here

Our pharmacy team is available to patients for advice and guidance. If you would like to discuss taking antidepressants with our pharmacists, they would be delighted to help.

Content last reviewed on:
August 11, 2023
Next review date:
August 11, 2025
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