How long does it take for antidepressants to work?

It usually takes around seven days before you begin to notice the effects of antidepressants. Contact your doctor if you haven't noticed any improvement after four weeks, as they may recommend increasing your dose or trying an alternative antidepressant.

During this time, you may experience side effects such as:

  • anxiety and agitation
  • drowsiness
  • blurred vision
  • nausea (feeling sick)

These side effects can be unpleasant at first, but it's important to persist with treatment, as your body will usually get used to the medication over time. Read more about the side effects of antidepressants.

How antidepressants work

Antidepressants work by increasing the levels of chemicals in your brain called neurotransmitters. The levels of neurotransmitters will rise gradually, which is why most people will need to take antidepressants for a few weeks before they start to work.

It's important that you continue to take your medicine at the prescribed dose to give it time to work properly. You should take your antidepressants for at least four to six weeks to see if they're effective. If they still aren't working after this time, your GP may consider changing to a different type or increasing the dose.

Stopping antidepressants

You shouldn't stop taking antidepressants suddenly, as this can cause withdrawal symptoms, such as:

  • flu-like symptoms
  • dizziness
  • vivid dreams
  • sensations in your body that feel like electric shocks

If you have been taking antidepressants for at least four weeks and you have felt little or no benefit, speak to your doctor. They may recommend increasing your dose or changing to a different antidepressant.

If you want to stop taking antidepressants, your doctor will normally reduce your dose gradually over a four-week period to reduce withdrawal symptoms.

Read the answers to more questions about mental health.

Further information:

Page last reviewed: 04/01/2016

Next review due: 31/10/2018