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Antidepressants


Expert reviewer, Dr Rahul Bhattacharya, Consultant Psychiatrist
Next review due May 2021

Antidepressants are a type of medicine used to treat depression. They’re sometimes prescribed for other health problems such as chronic pain, and for other mental health conditions such as anxiety or obsessive compulsive disorder. There are different types of antidepressant medicines, but the type most commonly prescribed is called a selective serotonin reuptake inhibitor (SSRI).

Young woman looking down in a moment of reflection

How do antidepressants work to treat depression?

Antidepressants work gradually over time to treat depression. Doctors don’t fully understand how they work yet, but they know they increase the amount of certain chemicals in your brain called neurotransmitters. Different antidepressant medicines act in different ways in the brain.

You may need to take antidepressants if you have moderate or severe depression and your symptoms make going about your daily life difficult. You may need antidepressants to help relieve your symptoms and manage your condition. You may also need to take antidepressants if you have other mental health conditions, such as post-traumatic stress disorder.

If your depression is mild, you might not need to take antidepressants at all. But if you’ve had mild depression for at least two years or you’ve previously had more severe depression, antidepressants may be an option for you.

Your doctor will talk you through your treatment options if antidepressants are a suitable treatment for you.

What are the different types of antidepressant?

The different types of antidepressant include:

  • selective serotonin reuptake inhibitors (SSRIs) such as citalopram, fluoxetine and sertraline
  • serotonin-noradrenaline reuptake inhibitors (SNRIs) such as duloxetine and venlafaxine
  • tricyclic antidepressants (TCAs) such as clomipramine and imipramine
  • monoamine oxidase inhibitors (MAOIs) such as tranylcypromine and phenelzine

Other types of antidepressants that fall outside of these categories include 5-HT2 receptor antagonists, such as mirtazapine. Another example is Vortioxetine – this might be an option if you have severe depression and other types of antidepressant haven’t worked for you.

The different types of antidepressant are all equally good at treating depression. Most people who need to take antidepressants are prescribed an SSRI. This is because they’re generally safer and their side-effects are tolerated better than other types of antidepressant. For more information on side-effects, see our section below: Side-effects.

Your doctor will talk you through which medicine is the best option for you. You may need to try different medicines before you find one that works for you.

Taking antidepressants

If your doctor prescribes you an antidepressant, they’ll want to see you again within a couple of weeks to see if it’s working for you. After that, you’ll need to go back each month for three months.

Some people find that their symptoms start to improve a few days after starting antidepressants, but it generally takes about two to four weeks. That’s why it’s important to keep taking your medicine, even if you don’t immediately feel better.

Once you’ve found an antidepressant that works for you, you’ll generally need to keep taking it for at least six months after your symptoms have gone away. This will help prevent your depression from coming back. If you’ve had depression that has come back in the past, you may need to continue taking your antidepressants for longer – for at least two years.

What are the known side-effects of antidepressants?

All antidepressants have side-effects. These are the unwanted effects you may get after taking your medicine. Antidepressants can affect your sex life: some men get erectile dysfunction after taking them, and women may get vaginal dryness. Antidepressants can also affect your desire to have sex (your libido). They can initially make you feel sick and, for a short while after you start taking them, may make you feel slightly worse. However, many of the side-effects are temporary and wear off after one to two weeks. When it comes to side-effects, some antidepressants are better than others.

The most commonly prescribed antidepressant is a selective serotonin reuptake inhibitor (SSRI). This is because the side-effects are more tolerable than those of other types of antidepressant.

Side-effects of SSRIs may include:

  • feeling sick
  • vomiting
  • tummy pain
  • diarrhoea
  • constipation
  • feeling dizzy
  • feeling anxious
  • feeling agitated
  • having trouble sleeping

You can ask your doctor for more information about the side-effects of other types of antidepressant.

There’s some evidence that SSRI antidepressants can increase suicidal thoughts in young people. Because of this, there are limits on their use in this age group. In the UK, fluoxetine is the only SSRI antidepressant licensed for use with young people. Its use in young people is always monitored closely by a psychiatrist.

It’s normal to experience some side-effects from taking antidepressants. But if you’re concerned about any side-effects you may be having from the antidepressant you’re taking, talk to your doctor. They may be able to prescribe you another type of medicine to see if you get on better with that. Don’t be tempted to miss doses or stop taking them completely. If you do, you may get discontinuation symptoms, such as feeling dizzy and sick, and difficulty sleeping. These symptoms are often mild and go away within a week or so, but they can be quite severe if you stop taking your medicine suddenly.

If you would like to stop taking your antidepressants, talk to your doctor first. They may help you reduce your dose slowly, over a period of weeks, to prevent these side-effects.

What are the alternatives to antidepressants?

If you have depression, it’s important to take care of yourself. There are some things you can do alongside your treatment to boost your mood. These can also help to distract you and look after your general health.

One example is to eat well. Eating a healthy, balanced diet with plenty of fruit, vegetables and fibre can help you maintain a steady level of energy and think clearly. Exercise is important too as this may help your symptoms. Your doctor may even prescribe a structured group physical activity programme as a treatment for depression. An exercise session usually lasts about an hour and you do them three times a week for around 12 weeks.

Other treatments for depression include:


These talking therapies help you to deal with your depression and the things that may be causing your symptoms in the first place. You can see a person who is trained in these types of therapy, in groups or on a one-to-one basis. There are also some tools and resources that you can use on your own. For more information on these and other types of therapy, see our information on: Talking therapies for mental health. If you have more severe depression, you may have these types of treatment alongside antidepressant medicines. If you have mild or moderate depression, you may have these therapies instead of antidepressants.

If you have particularly severe depression, another possible but much less common treatment option is electroconvulsive therapy (ECT). In ECT, an electric current is sent through your brain to trigger a fit. This treatment can ease some of the symptoms of depression, though it’s not certain exactly how it works. Sometimes, people with severe depression have this while waiting for antidepressants to take effect and they need more immediate treatment, or if treatment hasn’t worked. But it’s used far less now than in the past, possibly because of better talking treatments and the range of medicines for depression now available.

Your doctor will recommend the most suitable treatment for you. For more information about treatment options, see our Depression hub.


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Related information

    • Antidepressant drugs. NICE British National Formulary. bnf.nice.org.uk, reviewed 3 April 2018
    • Chronic pain syndrome. Medscape. emedicine.medscape.com, updated 22 February 2018
    • Depression in adults: recognition and management. National Institute for Health and Care Excellence (NICE), October 2009. www.nice.org.uk
    • Depression in adults. BMJ Best Practice. bestpractice.bmj.com, last updated 16 March 2018
    • Making sense of antidepressants. Mind. www.mind.org.uk, published 2016
    • Depression. Medscape. emedicine.medscape.com, updated 20 March 2018
    • Depression. NICE Clinical Knowledge Summaries. cks.nice.org.uk, last revised October 2015
    • Vortioxetine for treating major depressive episodes. National Institute for Health and Care Excellence (NICE), 25 November 2015. www.nice.org.uk
    • Personal communication, Dr Rahul Bhattacharya, Psychiatrist, 11 May 2018
    • Using antidepressants in children and young people. National Institute for Health and Care Excellence (NICE), 24 April 2018. www.nice.org.uk
    • Understanding depression. Mind. www.mind.org.uk, published 2016
    • Cognitive behavioural therapy (CBT) Mind. www.mind.org.uk, published October 2017
    • Information about ECT (electro-convulsive therapy). Royal College of Psychiatrists. www.rcpsych.ac.uk, published July 2015
  • Reviewed by Rachael Mayfield-Blake, Freelance Health Editor, May 2018
    Expert reviewer, Dr Rahul Bhattacharya, Psychiatrist
    Next review due May 2021



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