Antidepressants can take a week to have any impact, while the full effect can take up to four weeks. It is vital to warn patients of this as many will expect the effect to be instantaneous, so may become disillusioned about their medication and stop taking it. Once a patient is in remission, medication should normally be continued for a further six months to prevent relapse. However, for some patients, it may take longer.

Those who are at a high risk of relapse may take antidepressants as prophylaxis against future episodes. Patients may wish to stop their medication early for a variety of reasons. This is a decision that should be made with their GP. Ideally, the dose should be reduced gradually over a period of around four weeks. Stopping too quickly can lead to discontinuation reactions, which patients often confuse with addiction. However, antidepressants are not generally considered to be addictive.