Antidepressants

Antidepressants are medications that can help to relieve the symptoms of depression, anxiety disorders and some other conditions. They were first developed in the 1950s and have been used regularly since then. There are five main categories:

• SSRIs (Selective Serotonin Reuptake Inhibitors)
• SNRIs (Serotonin and Noradrenaline Reuptake Inhibitors)
• NASSAs (Noradrenaline and Specific Serotoninergic Antidepressants)
• Tricyclics
• MAOIs (Monoamine Oxidase Inhibitors).

There are other categories of antidepressant, which are less commonly prescribed today:

• Tetracyclics
• SARIs (serotonin antagonist and reuptake inhibitors)
• NDRIs (norepinephrine–dopamine reuptake inhibitors).

This resource focuses on how antidepressants are used for treating the symptoms of depression. However, a lot of the information in this resource will be helpful for people who are taking antidepressants for other conditions.

For information on how to safely stop taking antidepressants, take a look at our stopping antidepressants resource.

As with many other kinds of medications and treatments, we don't know for certain how antidepressants work. We do know that they affect the activity of certain chemicals in our brains. These are called neurotransmitters, and pass signals from one brain cell to another. The neurotransmitters most affected by antidepressants are serotonin and noradrenaline.

However, research suggests that antidepressants work on the brain in multiple ways that go beyond simple chemical reactions. This research suggests that they:

• influence how the body responds to stress
• improve our negative thinking
• stop or even reverse damage to brain cells.

Antidepressants should not usually be prescribed for mild depression. However, they are recommended for adults with moderate to severe depressive illness. This is when depression is significantly reducing the quality of someone’s life and having an impact on their day-to-day living. Antidepressants can be used alone or in combination with psychotherapies.

They should not normally be used for children and adolescents, unless their depression:

• has not responded to other treatments
• or is particularly severe.

Antidepressants can also be prescribed for some other conditions, including:

• Anxiety and panic disorders
• Obsessive compulsive disorder (OCD)
• Post-traumatic stress disorder (PTSD)
• Some eating disorders
• Chronic pain

Your doctor should explain why they are suggesting you take an antidepressant. They should also go through the potential benefits and risks of taking an antidepressant.

Research shows that antidepressants help to reduce the symptoms of moderate and severe depression in adults. But different people have very different experiences with these medications.

Some people will get better without antidepressants over time. However, generally people see an improvement in their symptoms and quality of life after using antidepressants. This is particularly the case when their depression is more severe. Some people find that antidepressants decrease the symptoms of their depression but have challenging side-effects. Others find that antidepressants just don’t work for them.

If your doctor does prescribe an antidepressant, they should give you a review around two weeks after you start taking them to monitor:

• how you are feeling
• whether you are getting side-effects
• and whether you need to carry on taking the antidepressant.

Antidepressants can’t remove the external factors that might have led to you developing depression. For example, if you are under a lot of stress at work or have experienced a bereavement, antidepressants of course won’t be able to take these things away. However, they can help to control the symptoms of depression and make these external factors easier to deal with. This is one of the reasons they are often used together with psychological therapies (also known as talking therapies).

All medications can have side-effects. Your doctor should discuss these with you before you agree to start using antidepressants. You should tell your doctor about any medical conditions you have or have had in the past. This can affect the type of antidepressant they recommend for you.

Below are some side-effects you might experience with the different types of antidepressant. The leaflets that come with the medication you are taking will have full details of these.

While the list of side-effects looks worrying, these will be mild for most people. They will also usually wear off over a couple of weeks as your body gets used to the medication.

SSRIs and SNRIs

• feeling agitated, shaky or anxious. This is often why people stop taking their antidepressant, especially if they have not been warned about it. However, this side-effect usually decreases a couple of weeks after starting the antidepressant.
• feeling or being sick
• indigestion or stomach aches
• diarrhoea or constipation
• loss of appetite
• dizziness
• blurred vision
• dry mouth
• sweating
• not sleeping well (insomnia), or feeling very sleepy
• headaches
• low sex drive
• difficulties achieving orgasm during sex or masturbation
• in men, difficulties obtaining or maintaining an erection (erectile dysfunction).

Rarely people can experience more persistent sexual side-effects after they have stopped taking SSRIs. The term ‘post SSRI sexual dysfunction’ (PSSD) has been used by some people to describe these symptoms. For these people, PSSD can have a significant and distressing impact on their lives.

More research is needed to understand why this happens and how common it is. It is important that people experiencing ongoing sexual side-effects receive appropriate and timely support.

NASSAs

The side-effects for NASSAs are very similar to SSRIs. They can make you feel drowsy, and cause weight gain, but they cause fewer sexual problems. 

Tricyclics

These can often cause:

• dry mouth
• slight blurring of vision
• constipation
• problems passing urine
• drowsiness
• dizziness
• weight gain
• excessive sweating (especially at night)
• heart rhythm problems, such as noticeable palpitations or a fast heartbeat (tachycardia).

As with SSRIs/SNRIs, these side-effects will usually be mild and wear off over a couple of weeks.

MAOIs

MAOIs are a class of antidepressants that are less commonly prescribed. They tend to only be used by specialists. This is mainly because people who take them need to follow a strict diet that avoids foods high in Tyramine (an amino acid). If this diet isn't followed, there is a risk of developing dangerously high blood pressure. In general, MAOIs are well tolerated. They can be effective in certain situations where other antidepressants haven't worked or cause unpleasant side-effects. 

If you are using any kind of antidepressant and experience side-effects that last for longer than a few weeks or become unbearable, speak to your doctor. You might also find it helpful to tell your friends or family that you are starting antidepressants. This can help them to support you if you are experiencing side-effects.

For full information on the antidepressant you are taking, including side-effects, please visit the Electronic Medicines Compendium (EMC). Type in the name of the medication in the search box at the top of the page. You should also be given a paper copy of this information when you are given your medication. If you don’t receive one, ask your pharmacist to provide you with one.

Depression can cause you to feel suicidal. Some people also experience increased suicidal thoughts when they start taking antidepressants. The risk of this happening may be higher in children and adolescents. Because of this, if they are prescribed antidepressants they should be closely monitored for suicidal thoughts by the prescribing doctor or another healthcare professional.

It is very important that if you are experiencing suicidal thoughts or feelings, you report these to your doctor straight away. They might suggest that you stop taking your antidepressant.

If you feel you are at risk of hurting yourself, call 999 or go to your nearest A&E.

If you are not in an emergency but need help, call NHS 111.

Some antidepressants make you sleepy and slow down your reactions, so cannot be taken if you are driving or operating machinery. You should check with your doctor and look at the leaflet that comes with the medication to be sure.

If your condition or medication effects your ability to drive, you must inform the Driver and Vehicle Licensing Agency (DVLA).

Stopping antidepressants can be difficult for some people, while other people are able to stop relatively easily.

Antidepressants should never be stopped straight away. We have developed a separate information resource on stopping antidepressants that looks at this area in detail. It provides advice on how to gradually stop.

Withdrawal symptoms usually appear within days of stopping the antidepressant and include:

• headaches
• light-headedness
• nausea
• difficulty sleeping
• vivid or frightening dreams
• electricity-like sensations (also known as ‘zaps’)
• rapid mood changes, including anxiety and irritability.

If the depression returns after weeks or months, this is most likely due to a return of the original condition rather than to withdrawal symptoms.

You can find out more about this in our stopping antidepressants information resource.

Some people experience unpleasant withdrawal symptoms when they stop using antidepressants. In most people, these withdrawal symptoms can be minimised by reducing the antidepressant’s dose slowly over a few weeks. Although some people may need to start taking it again and reduce it even more slowly.

It may feel as though you are addicted to the antidepressant if you can’t stop taking them when you would like to. This is not quite the same as being ‘addicted’.

Addiction generally means that you:

• feel an urge or craving to use a substance
• lose control over your use of the substance
• experience pleasure, or ‘a high’ when you use it.

Addiction can happen with substances such as alcohol, nicotine and benzodiazepines.

It can be hard to stop taking antidepressants, but this is more accurately described as physical dependence.

The term ‘physical dependence’ has become confused with addiction. Physical dependence means that your body has adapted to the presence of a substance or medication.

This produces tolerance and withdrawal effects because the body ‘misses’ it when it is gone. A drug does not need to produce a ‘high’ to be dependence-forming.

Here you can find a list of the common antidepressants, their trade names in the UK, and their type.

*This antidepressant regulates serotonin but in a different way compared with classic antidepressants. It also acts on melatonin which is a hormone involved in sleep.

This is not an exhaustive list of all antidepressants. There are other drugs that are sometimes used in specialist settings.

Many people need to take medications for physical or mental health problems before, during and after pregnancy. Some medications have been used in pregnancy for many years. Others are known to be dangerous in pregnancy (such as sodium valproate).

Decisions about whether to continue, change or stop taking antidepressants in pregnancy or while breastfeeding are not straightforward or easy. There are many factors to consider, including:

• the medication you are taking
• your personal history of illness
• your response to treatment
• your views.

Any risks from taking medication, including antidepressants, in pregnancy needs to be balanced against the risk of becoming unwell without treatment. You will need to have a careful discussion with your GP or psychiatrist. 

Research studies have looked at many thousands of women who have taken antidepressants in pregnancy. These studies are not always easy to interpret, as many factors affect outcomes for babies. Your GP or psychiatrist can help you to understand what the current research says about different medications in your personal situation.

Many women do take antidepressants in pregnancy. There is more information about the more commonly used antidepressants, such as SSRIs, and their use in pregnancy. For newer antidepressants, such as vortioxetine, there is much less information. You can find information about individual antidepressants on the Best Use of Medications in Pregnancy website.

If you are not pregnant yet

If possible, you should talk to your doctor before you become pregnant. However, many pregnancies are unplanned and you may have to make decisions about medication when you are already pregnant.

If you are already pregnant

If you are already pregnant, you should see your doctor as soon as possible. It is very important that you don’t stop your medication suddenly, unless your doctor tells you to. Stopping antidepressants suddenly can lead to a relapse in your mental health problems. It can also cause unpleasant side-effects. You need to think about the severity of your previous illness before deciding whether stopping medication is safe. Many women relapse after stopping medication in pregnancy.

For further information, see our leaflet on mental health in pregnancy.

How long you take an antidepressant for depends on why you were prescribed them, and whether you have had to take them before.

If this is the first or second time you are taking antidepressants, it is best to continue to take them for at least six months after you feel better. If you stop the medication before then, the symptoms of depression are more likely to come back. If you have had many episodes of depression before, you may need to take them for longer. However, there should be an ongoing discussion with your doctor about when and how to stop them.

It is worthwhile thinking about what might have contributed to you becoming unwell. Sometimes, mental health problems like depression just happen, and there is no obvious reason why. However, there might be things in your life that were difficult and contributed to you becoming unwell. For example, financial stress, loneliness or losing a job. Sometimes stresses are completely unavoidable. However, there might be things you can do to make it less likely that you will become unwell again in the future. 

Sometimes depression comes back, even if you have done everything you can to stay well. If this happens, you might need to:

• start taking antidepressants again after consulting with your GP
• change your antidepressant
• or try another form of treatment such as talking therapies.

Some people need to take antidepressants for a long time to stay well. This can be frustrating if you hoped that you would be able to stop taking your antidepressant. It is important to remember that you might be able to stop taking antidepressants again in the future. This does not mean you have ‘failed’.

It's difficult to say. It depends why they were prescribed, how bad your depression is and how long you've had it for. Sometimes depression gets better without any treatment, or with other treatments like talking therapies.

Antidepressants can make it easier for you to engage in other treatments like talking therapy. It can also make talking therapy more effective.

Your doctor should talk this through with you before they prescribe you antidepressants. They should make sure that you fully understand the benefits and risks of taking and not taking antidepressants.

Here are some helpful things for you to know if you are taking antidepressants:

• If you are struggling with the antidepressant you are taking, speak to your doctor. They should help you to find a type of medication or dose that works for you without giving you unmanageable side-effects. If you have tried multiple antidepressants, they might want to look at alternatives.
• Try not to be put off if you get some side-effects. These can be unpleasant, and it is understandable that people sometimes stop taking their antidepressants as a result. However, most side-effects wear off in a couple of weeks. If you can, try to wait for this length of time before stopping. However, if the side-effects are intolerable or you feel suicidal, speak to your doctor straight away.
• Try not to miss a dose, as this might cause you to develop withdrawal symptoms. If you do miss a dose, just take your next dose as usual. Don’t ‘make up’ for the missed dose by taking more than usual.
• Most people find that antidepressants take 1-2 weeks to start working. For some people it takes up to 6 weeks for them to start feeling the full effect. Even if you aren’t feeling the benefits of your antidepressant yet, try to keep taking them for a few weeks before stopping. You might find that things improve.
• Speak to your doctor about drinking alcohol. Most antidepressants do not react with alcohol. However, some antidepressants can make you sick or drowsy if you drink alcohol while you are taking them, or increase the effects of alcohol.
• If you think that antidepressants are having a negative effect on your physical or mental health, speak to your doctor.
• Antidepressants can interact with certain foods and medications. For example, grapefruit can interact with the antidepressant sertraline. You should ask your doctor or pharmacist if your antidepressant interacts with any foods or medications, and read the information that comes with your prescription carefully. If you start a new medication, check the information that comes with it to be certain that it does not interact with your antidepressant.

Psychological therapies (talking therapies)

There are a number of helpful talking therapies for depression. These are often recommended as a first option, or used in combination with antidepressants.

• Counselling – Counselling can be useful in mild depression, and can help you develop problem solving techniques. Counselling can help when the depression has been caused by difficulties in your life.
• Cognitive behavioural therapy (CBT) – CBT can help to improve your state of mind by teaching you to spot the links between your thoughts, actions and feelings. Unlike other talking therapies, it focuses less on your past and more on what is happening in your present.

For information about these and other forms of talking therapy, see our information on:

• psychological therapies
• and cognitive behavioural therapy (CBT).

Other medication

If you do not improve after taking an antidepressant your doctor may suggest trying another medication. This could include adding to or replacing your current antidepressant with:

• another antidepressant of a different type
• an antipsychotic (for example, aripiprazole, olanzapine, quetiapine or risperidone)
• lithium
• lamotrigine
• triiodothyronine (liothyronine)

These options are commonly used in the UK. However, please note that this is not a comprehensive list.

Electroconvulsive therapy (ECT)

Electroconvulsive therapy (ECT) is an effective treatment for some types of severe mental illness. ECT may be considered when other treatment options, such as psychotherapy or medication, have not been successful or when someone is very unwell and needs urgent treatment. 

Herbal remedies

Herbal remedies come from plants and are not prescribed on the NHS in the UK.

Some herbal remedies have been shown to have positive effects on people with depression. One of these is called Hypericum, and is made from a herb called St John’s Wort. Because it is a herbal treatment, it is less well researched and there are less rules around how it is sold. The amounts you get can vary depending on where you buy it.

St John’s Wort can be dangerous if it is taken with SSRI antidepressants and other medications. It can also interfere with other medications like the contraceptive pill. If you are thinking about taking any herbal remedies, speak to your doctor first.

General wellbeing

It is important to think about your general wellbeing. There are lots of things you can do to make yourself feel better, so you are less likely to become depressed again. These can include:

• finding someone you can talk to
• keeping physically active
• drinking less alcohol and not taking recreational drugs
• eating well, for example eating more fish, fruit and vegetables
• using self-help techniques to help you relax
• finding ways to solve any practical problems that have brought the depression on
• peer support – you might find it helpful to meet with people who are experiencing similar problems to you. Speak to your GP about peer support groups that might be appropriate for you.

For some tips on self-help, see our information resource on depression.

Social prescribing

Social prescribing helps to connect people to community services and groups local to them. This can help to support their mental and physical health.

For example, if you enjoy gardening, social prescribing might involve putting you in touch with a weekly gardening group near you. You will be able to meet with others and spend time together doing what you enjoy.

You can find out more about this in our social prescribing resource.

Light

Some people find their mood is affected by the season. This is called seasonal affective disorder (SAD). If you get depressed every winter but improve when the days become longer, you may find a light box helpful. This is a source of bright light which you have on for a certain time each day and which might help to make up for the lack of light in the winter. Speak to your doctor if you think you might be experiencing SAD.

If you have any questions about antidepressants, take a look at some other sources of information here, or speak with your doctor.

• Electronic Medicines Compendium – Summaries of Drugs and Patient Information Leaflets (PILs). Information on thousands of licensed medicines available in the UK.
• NHS advice on antidepressants – Information from the NHS on the use of antidepressants. This covers cautions, dosage, side-effects and alternatives.
• Mind, antidepressants – Information about antidepressants from the mental health charity, Mind.
• Rethink Mental Illness, antidepressants – Information about antidepressants from the mental health charity, Rethink Mental Illness.

This information was produced by the Royal College of Psychiatrists’ Public Engagement Editorial Board (PEEB). It reflects the best available evidence at the time of writing.

Lead author: Professor Wendy Burn

Expert review: The Royal College of Psychiatrists’ Psychopharmacology Committee

Experts by experience: Fiona Rajé and Victoria Bridgland

Full references available on request.