When prescribing antidepressants your GP will usually select the lowest possible dose thought necessary to improve your symptoms.

This approach is intended to reduce the risk of side effects. If this dose proves ineffective, it can be gradually increased.

Antidepressants are usually taken in tablet form. Depending on the type of antidepressant prescribed and the severity of your depression, you will usually have to take one to three tablets a day.

It usually takes between two and four weeks before you begin to notice the effects of antidepressants. Contact your doctor if you haven't noticed any improvement after 4-6 weeks, as they may recommend increasing your dose or trying an alternative antidepressant.

It is usually recommended that a course of antidepressants lasts at least six months to prevent your condition recurring when you stop. However, if you have experienced previous episodes of depression, a two-year course may be recommended and some people with recurrent illness are advised to carry on taking medication indefinitely.

The recommended course of treatment depends largely on the benefits experienced balanced against the side effects of the medication. If your illness is severe and the medication is effective, treatment will often be continued. If your illness is mild and the medication doesn’t help and causes side effects, then continued treatment will not be recommended.

Missed or extra doses

It's important to try not to miss any of your doses as this could make your treatment less effective.

If you do miss one of your doses, take it as soon as you remember unless it is almost time to take your next dose, in which case you should just skip the missed dose. Don't take a double dose in order to ‘make up’ for the one you missed.

If you take more tablets than prescribed, contact your GP as soon as possible for advice. If this is not possible, contact your local out of hours service, or call NHS 111. Taking a double dose is unlikely to be harmful, but you should only do it if advised by a medical professional.

Stopping antidepressants

You should not suddenly stop taking antidepressants, even if you feel better. Stopping suddenly can lead to withdrawal symptoms such as:

• stomach upsets
• flu-like symptoms
• anxiety
• dizziness
• sensations in the body that feel like electric shocks
• seizures (fits)

Stopping antidepressants too soon can cause your condition to recur and stopping before 3-4 weeks may mean the medication has not yet had a chance to take effect.

If your GP or mental health specialist decides to stop your course of antidepressants, they will reduce the dose gradually over a few weeks.