What antidepressants do
Antidepressants are medicines that treat the symptoms of depression. They are also used for other conditions, such as anxiety disorders and some types of long-term pain.
They are not a quick fix, and they work best as part of a wider plan. For many people, they ease symptoms enough to make daily life more manageable and to make the most of other support, such as talking therapy.
The NICE guideline on depression in adults (NG222) does not recommend antidepressants as a routine first treatment for less severe depression, unless the person prefers them. For more severe depression, NICE lists a combination of CBT and an antidepressant as the first option. Treatment for depression explains the full range.
Main types
The NHS describes several groups of antidepressant. The NHS says all types generally work about as well as each other for depression. The choice usually depends on side effects, other health conditions, other medicines you take and what has worked for you before.
| Type | Examples | Notes |
|---|---|---|
| SSRIs (selective serotonin reuptake inhibitors) | sertraline, citalopram, escitalopram, fluoxetine, paroxetine | The most widely used type, and usually tried first |
| SNRIs (serotonin and noradrenaline reuptake inhibitors) | duloxetine, venlafaxine | Another commonly used type |
| Mirtazapine (a NaSSA) | mirtazapine | Usually taken at bedtime as it can cause sleepiness; can increase appetite |
| Tricyclic antidepressants (TCAs) | amitriptyline, nortriptyline | Older type; also used for some other conditions, such as some types of pain |
| Other types | trazodone; MAOIs | The NHS says MAOIs are now rarely used for depression |
The NHS website has a page for each of these medicines, with information on dose, side effects and interactions.
How long they take to work
Antidepressants do not work straight away. The NHS says they usually take 1 to 2 weeks to start having an effect and can take up to 8 weeks to work fully.
Some side effects can appear before the benefits, which can be discouraging. It is worth keeping going and talking to your prescriber rather than stopping early.
NICE recommends a review of how treatment is going 2 to 4 weeks after starting. For people aged 18 to 25, or at increased risk of suicide, NICE recommends a review 1 week after starting or after a dose increase.
If an antidepressant has not helped after a fair trial, options include adjusting the dose or trying a different medicine. The NHS notes that some people need to try more than one treatment.
How long to take them
The NHS says people usually take antidepressants for at least 6 months after they feel better. Stopping too soon increases the chance of depression coming back. NICE adds that treatment should be reviewed regularly, and at least every 6 months for people who carry on taking an antidepressant to prevent depression returning. People at higher risk of relapse may be advised to take them for longer.
Side effects
Side effects are common, especially in the first few weeks. The NHS says many ease after a couple of weeks as your body gets used to the medicine, but some can continue.
Common side effects listed by the NHS include:
- feeling sick, indigestion or changes in appetite
- headaches, dizziness or drowsiness
- sleep problems
- dry mouth or sweating
- weight gain
- mood changes, such as feeling irritable or emotionally numb
- sexual problems, such as low sex drive or difficulty reaching orgasm
Side effects vary between medicines. Mirtazapine, for example, is more likely to cause sleepiness and increased appetite. Tell your prescriber if side effects are hard to live with. There are often alternatives. You can also report suspected side effects to the MHRA Yellow Card scheme.
Alcohol and other medicines
The NHS advises caution with alcohol. Drinking while taking antidepressants can make depression worse, or make you feel sleepy or dizzy. Ask your prescriber or pharmacist what is sensible for you.
Some medicines and remedies interact with antidepressants. The NHS specifically mentions St John’s wort, a herbal remedy that should not be taken with antidepressants. Always tell doctors, dentists and pharmacists what you take, including over-the-counter and herbal products.
Pregnancy and breastfeeding
If you are pregnant, planning a pregnancy or breastfeeding, talk to your doctor before starting, changing or stopping an antidepressant. The NHS says your doctor will discuss the benefits and risks with you. Some antidepressants are considered suitable during pregnancy.
Do not stop an antidepressant suddenly because you find out you are pregnant. Stopping can cause withdrawal symptoms and a return of depression. Speak to your GP, midwife or prescriber promptly so you can decide together. Types of depression has more on depression during and after pregnancy.
Stopping antidepressants safely
When it is time to stop, your prescriber will help you plan how to reduce the dose gradually. The NHS says this is usually done over several weeks or months.
NICE recommends reducing the dose in steps, with each step a proportion of the previous dose, for example half. This means the reductions get smaller as the dose gets lower. NICE says the speed and length of the process should be led by, and agreed with, the person taking the medicine. It also notes that some antidepressants, such as paroxetine and venlafaxine, are more likely to cause withdrawal symptoms, so particular care is needed.
The Royal College of Psychiatrists publishes a patient guide, Stopping antidepressants, that explains tapering and withdrawal in more detail. It is a useful thing to read and discuss with your prescriber.
Withdrawal symptoms
Withdrawal symptoms, sometimes called discontinuation symptoms, are the body’s reaction to a lower dose or to stopping. NICE lists symptoms that can include:
- dizziness, unsteadiness or vertigo
- electric shock-like sensations
- anxiety, irritability, low mood, tearfulness or panic
- restlessness or agitation
- problems sleeping
- sweating, nausea, palpitations, tiredness, headaches or aches
NICE says withdrawal symptoms can be mild, may start within a few days of reducing or stopping, and usually go away within 1 to 2 weeks. For some people withdrawal is more difficult, with symptoms lasting several weeks, and occasionally several months. They can sometimes be severe, particularly if the medicine is stopped suddenly.
Withdrawal can be confused with depression returning. If you get symptoms while reducing, contact your prescriber. For more severe withdrawal symptoms, NICE says prescribers should consider restarting the previous dose and then reducing more slowly, in smaller steps.
When to seek a specialist review
A psychiatrist’s review can help if:
- you have tried two or more antidepressants without much improvement
- side effects have made treatment hard to continue
- you have had difficulty coming off an antidepressant
- you take several medicines, or have other health conditions that complicate choices
- there is doubt about the diagnosis, such as possible bipolar disorder
Seeing a psychiatrist explains what a review involves.