Antidepressants: What to Know Before and After Starting

Starting an antidepressant can bring questions and worries. This article explains general facts from the UK's National Health Service (NHS), the World Health Organization (WHO) and MedlinePlus. It does not replace advice from the doctor who prescribes your medicine, and it gives no doses.

Who are antidepressants for?

The NHS says antidepressants are prescribed by a doctor, usually for moderate or severe depression. Most people with moderate or severe depression benefit, but not everyone does, and it may take trying more than one medicine. The WHO states that antidepressants are not needed for mild depression and that for moderate and severe depression they can be combined with psychological treatment. According to the NHS, an antidepressant combined with cognitive behavioural therapy (CBT) usually works better than either alone.

Classes of antidepressants

The NHS describes several classes. A doctor decides which one may suit a person, based on their health, other medicines and side effects.

• SSRIs: usually the first choice. The NHS says they work about as well as older types with fewer side effects, and side effects often ease over time.
• TCAs: older antidepressants whose side effects can include dry mouth, blurred vision and constipation.
• SNRIs: may be more effective than SSRIs in some studies, but can raise blood pressure.
• Other medicines: some, such as mirtazapine, can cause drowsiness, and others are used when earlier treatments have not worked.

The NHS says all the classes are thought to work about equally well, though side effects differ.

How long do they take?

According to the NHS, symptoms should start to improve within about 4 weeks of starting an antidepressant. A doctor or specialist nurse usually reviews you every 1 to 2 weeks for at least the first 4 weeks. MedlinePlus adds that medicines can take time to work and can have side effects, so it may be necessary to try more than one.

Side effects and safety

• Side effects differ by medicine and person. Tell your doctor about any that worry you rather than stopping on your own.
• Contact a doctor straight away if feelings of hopelessness or thoughts of suicide begin or get worse after starting a medicine, the NHS advises.
• Children and teenagers need extra care. The NHS says under-18s have a higher risk of self-harm and suicidal behaviour with these medicines, so a specialist must approve any prescription, and the WHO says antidepressants should not be used for children and are not first-line for teenagers.
• The NHS says St John's wort can interact with other medicines, including the contraceptive pill, and should be avoided in pregnancy and breastfeeding. Always ask a doctor or pharmacist before combining any herbal product with a prescription.

Staying on treatment and stopping

The NHS says people usually continue the same dose for at least 4 to 6 months after symptoms ease. Those who have had several episodes may need longer-term treatment, reviewed regularly. When stopping, doses should be reduced gradually. Withdrawal symptoms are usually mild and last up to one to two weeks, but can be more severe, and the NHS says they seem most likely with certain medicines. See a doctor if they persist or get worse.

MedlinePlus is clear: do not stop medication without talking to your provider.

When to see a doctor

Speak to your doctor if you think a medicine is not helping, if side effects bother you, if you are pregnant or planning pregnancy, or if you feel worse after starting. If you have thoughts of harming yourself, contact a doctor, counsellor or crisis help line right away. Help lines exist in India and the United States, and a local health service can tell you which are available.

Do not stop or change prescribed treatment without talking to your doctor.

In an emergency, call your local emergency number (112 in India, 911 in the United States).