NEW: Take control of your health with our easy at-home blood test kits. Get your test.

On this page

    What are antidepressants?

    On this page
    1. How do antidepressants work?
    2. Do I need antidepressants?
    3. How long until antidepressants work?
    4. What does it feel like when antidepressants kick in?
    5. How long do I have to take antidepressants?
    6. Types of antidepressants
    7. What are the side effects of antidepressants?
    8. How to get antidepressants
    9. Taking antidepressants
    10. Other treatments for depression

    Reviewed by our clinical team

    Bottle of antidepressants

    If you’ve been feeling depressed, and you think you need help, it’s a really good idea to book an appointment with your GP.

    Though we tend to think of our GPs as the people we go to for chest infections and tummy bugs, they’re also trained to offer advice and treatment for mental health issues. Your GP can refer you for therapy or counselling. They might also offer to prescribe antidepressants.

    For people with severe depression, antidepressants can be really effective. However, because this medication isn’t suitable for everyone, it’s important to get a prescription from your doctor or specialist. In this article we’re going to talk a little bit about antidepressants, how antidepressants work, feel and what you might be prescribed them for. 

    How do antidepressants work?

    Antidepressants work by affecting the neurotransmitters dopamine, noradrenaline or serotonin. Neurotransmitters are the body's chemical messengers: they are helping to transmit messages between (brain) cells.

    You may find that taking antidepressants helps you feel happier and less worried, and that you can get back to your daily routine, enjoying work, hobbies, and socialising. Antidepressants can also help ease suicidal thoughts, and the impulse to self-harm.

    However, brain chemistry is complex, and everybody is different. This is why antidepressants don’t work for everybody.

    Another thing to bear in mind is that antidepressants won’t treat the root causes of depression. This is why they’re normally given as part of a combination treatment that incorporates some kind of talking therapy.

    Do I need antidepressants?

    Antidepressants are usually prescribed for moderate to severe depression that's having a major impact on your day-to-day life. For mild depression talking therapy is usually offered to start with.

    But in addition to treating depression, some antidepressants can be prescribed for:

    • Anxiety
    • Post-traumatic stress disorder (PTSD)
    • Obsessive compulsive disorder (OCD)
    • Phobias
    • Eating disorders
    • Chronic pain

    How long until antidepressants work?

    Antidepressants normally have to be taken for one or two weeks before you start to notice a difference. It may take one or two weeks to get used to the tablets, and you may experience side-effects , but this should all pass after two weeks.

    It’s important to stick it out in the first two weeks of taking a new antidepressant, and not assume that the treatment doesn’t work because you don’t feel different straight away.

    However, it’s also important to speak to your doctor if you don’t feel a change in your mood after two to four weeks. They may need to increase the dose, or change your tablets.

    If the first antidepressant you try doesn’t work for you, don’t be disheartened. Sometimes it takes a little while to find the antidepressants that suits you best.

    What does it feel like when antidepressants kick in?

    As mentioned, it might take a couple of weeks before you start to feel any difference from taking antidepressants. Initially you might not notice any difference in your mood, but you could start seeing some other benefits quite quickly, for example improved sleep. 
    Like all medications you might experience some side effects, these can vary depend on the type of antidepressant you’re taking. But some common side effects include nausea, headaches and decreased alertness. We’ll discuss this further below. 

    How long do I have to take antidepressants?

    It depends on your situation. Usually your doctor will prescribe antidepressants for at least six months, but some people might need to take them for much longer.

    Types of antidepressants

    There are quite a few different types of antidepressants, so here’s a brief overview of the most common types.

    Selective serotonin reuptake inhibitors (SSRIs)

    These work by making serotonin act for longer on your brain and body (serotonin is a messenger chemical that’s thought to have a good impact on mood, emotion and sleep). Generally, these cause fewer side effects and there’s less risk of overdosing, so lots of people find them easier to take than other antidepressants, especially if it’s the first time you’ve been prescribed antidepressants.  

    SSRIs are the most commonly prescribed type of antidepressant. Common brands include: 

    • Fluoxetine (Prozac)
    • Citalopram (Cipramil)
    • Certraline (Lustral)

    Serotonin and noradrenaline reuptake inhibitors (SNRIs)

    SNRIs work in a similar way to SSRIs, but as well as working on serotonin, they also work on noradrenaline (another messenger chemical that impacts your body’s ‘fight or flight’ response). 

    Most people won’t experience many side effects with these drugs, and SNRIs such as duloxetine (Cymbalta) are commonly prescribed.


    These work in the same way as SNRIs, making serotonin and noradrenaline work longer in your body and mind. But they also affect some other chemicals in the body, so they can have some unpleasant side effects. 

    Monoamine oxidase inhibitors (MAOIs)

    MAOIs are not so commonly used these days, and they can only be prescribed by a psychiatrist. MAOIs make it difficult for an enzyme called monoamine oxidase to break down noradrenaline and serotonin. This means that serotonin and noradrenaline work longer in your body and mind. 

    This type of drug can have potentially dangerous interactions with certain medications and foods, so you have to follow a strict diet. This is because MAOIs block the breakdown of a substance called tyramine, a naturally occurring substance in lots of food a drinks. A build up of tyramine can cause dangerous increases to blood pressure. 

    If you don’t respond to these “standard” antidepressants, your doctor may offer you another, less commonly prescribed, type.

    What are the side effects of antidepressants?

    Different antidepressants can cause different side effects.

    In many cases, side effects will occur soon after you start treatment, but will wear off as your body gets used to the medication. For some people, however, side effects may persist.

    If you’re taking SSRIs or SNRIs, you might experience some of the following in the first few weeks:


    Headaches are a very common side effect of antidepressants. Speak to your GP or consult your patient information leaflet to check if there’s any painkillers you can take while you’re taking your antidepressants. 


    Drowsiness and not feeling as alert can also be very common side effects when you first start taking antidepressants. Try not to put too much pressure on yourself, when you first start taking these medications, it can take your body a little bit of time to get used them. 

    Nausea, vomiting, stomach aches or digestive issues

    Digestive issues can be a common side effect when taking antidepressants. From feeling sick to vomiting, tummy ache, indigestion, constipation or diarrhoea, these can be varied. If you’re worried about the symptoms, or if you think you might have been sick quite soon after taking your tablet, speak to your GP or consult the patient information leaflet. 

    Problems sleeping

    Lots of people with mental health conditions experience problems sleeping and this is something that can quickly get better. But some people might actually find taking the tablets impacts their sleep patterns, particularly as you get used to the medication. 

    Feeling anxious or agitation

    While antidepressants are there to hopefully help you feel less depressed and in some cases less anxious, there is the chance that they have the opposite impacts, making you feel more agitated or anxious. If you’re worried about your symptoms, it’s always best to get in contact with your GP or specialist to make sure everything is as it should be. 


    Feeling dizzy or lightheaded can be a side effect of taking antidepressants. This might pass after your body gets used to the medication, but if it doesn’t pass, it would be a good idea to speak to your GP. 

    Loss of sex drive or sexual dysfunction

    Depression and other mental health conditions can impact your sex life. This can include things like erectile dysfunction and decreased sex drive. But antidepressants can also sometimes impact these things too. It’s good to keep an eye on these symptoms and if it’s affecting your day-to-day life or relationship, it might be worth speaking about this with your GP. 

    For more information about stress and sexual function here, or visit our men's health hub

    Side effects of other types of antidepressants

    Other types of antidepressants may cause slightly different side effects. Tricyclics, for instance, can cause a dry mouth, blurred vision, and night sweats.

    Rare side effects

    In rare cases, antidepressants can cause an increase in suicidal thoughts and the impulse to self-harm. If you ever find yourself thinking of self-harming or having suicidal thoughts, contact your doctor or go to the hospital immediately.

    How to get antidepressants

    Because antidepressants aren’t suitable for everyone, it’s important to get them on prescription from a UK healthcare professional. Trying to obtain them illegally from an unregulated source could be really dangerous.

    Your GP will probably prescribe a standard antidepressant like an SSRI, but if standard antidepressants don't work for you, or things are getting worse your GP might refer you on to a psychiatrist. 

    Taking antidepressants

    You should only ever take your antidepressants as directed by the GP or specialist who prescribed them. There will also be lots of guidance in the patient information leaflet inside the packaging of your tablets. 

    If you don’t think an antidepressant is working, or if you’re getting troublesome side-effects, speak to your prescribing doctor for advice. 
    Don't stop your antidepressants without speaking to your doctor first- antidepressants need to be reduced gradually over a few days; stopping them "cold" might make you feel even worse.

    While taking antidepressants, you’ll also need to make sure that you avoid certain types of medication or herbal remedy. Please tell your doctor about any supplements you take and also make sure you read the patient leaflet that comes with your tablets.

    If you’re taking SSRIs or SNRIs, you shouldn’t take any other medication that increases levels of serotonin in the brain, such as St John’s Wort or 5-HTP. If you do, you could “overdose” on serotonin and develop a dangerous condition called serotonin syndrome.

    For more information about medications and other substances to avoid, consult this guide from the NHS.

    Other treatments for depression

    If your doctor doesn't feel antidepressants are the best way forward at this moment in time, or if you don’t want to take medication, there are some good alternatives, including:

    Talking therapies like CBT and counselling 

    Talking therapies involve working with a trained therapist to help you cope and manage your mental health. Cognitive behaviour therapy (CBT) for example helps you change the way you think and act to help you deal with potentially stressful situations. 
    Counselling is about talking with a counsellor to help you find ways to deal with situations or relationships which you might be struggling with. 


    Mindfulness is all about paying more attention to the present, to focus on how you’re feeling, what you’re thinking and the world around you. This can be used to help us understand ourselves better and have more appreciation where we are. 

    Art therapy, creative therapy or ecotherapy

    These types of therapy help you express your feelings through creative activities like painting, drawing, sewing, music, dance or drama therapy, or activities outside like walking and cycling in nature. 
    These types of therapy can give you a break from your symptoms and calm the mind.   

    In England, you can refer yourself directly for talking therapy through the NHS. Visit this page to find a service near you.

    While it’s not always easy to get yourself out of depression without help from a professional, making changes to your lifestyle can help. Changes that can boost your mood include eating a healthy and balanced diet, exercising regularly, cutting back on alcohol, and getting more sleep.

    For more help and guidance, check out the free resources available at Mind and the NHS or visit our mental health hub. If you’re struggling and you need help right away, this page contains information about mental health services and helplines.


    LloydsPharmacy Online Doctor

    This service operates in the United Kingdom only

    LloydsPharmacy Online Doctor

    This service operates in the United Kingdom only

    Visit IE Online Doctor Continue with UK service
    LloydsPharmacy Online Doctor

    This service operates in the Republic of Ireland only

    Continue with Irish Service Continue with UK Service