About the study

ANTLER, ANTidepressants to prevent reLapse in dEpRession

The aim of this study is to evaluate the effectiveness of long-term maintenance treatment for depression in the UK.


In 2013, there were over 53 million prescriptions for antidepressants in the UK, many of which were repeat prescriptions. This is because they are often taken continuously by patients, to prevent future episodes of depression (maintenance treatment). The current NICE guidelines recommend people "at risk of relapse" should remain on maintenance antidepressants for two years, although there is currently little evidence to support this policy. UK surveys have shown that between 5% and 8% of the general public are taking antidepressants, and up to half of these have been taking them long-term. Many of these people no longer show symptoms of depression, and so the benefits of continuing treatment are debatable.

Who can participate?

Adults with depression who have been taking antidepressants for at least 9 months, and are willing to consider stopping their medication.

What does the study involve?

After the initial interview which should take about 1 hour and 30 minutes, eligible participants are randomly allocated into one of two groups:

  • Those in the first group continue to take their medication (citalopram 20mg, sertraline 100mg, fluoxetine 20mg or mirtazapine 30mg) for the entire study period (12 months). 
  • Those in the second group will take medication that  contain a reducing amount of active antidepressant for the first two months to lower the risk of withdrawal symptoms, and then take a dummy pill (placebo) for the remainder of the study.

Participants will need to complete further interviews at 3, 6, 9 and 12 months after the initial visit. This will enable us to follow them through their treatment and capture important information. The interviews at 3, 6, 9 and 12 months can take place either at the GP surgery, University or participant's home and will last about 40 minutes.

Who is funding and organising the research?

The research is being organised by University College London in collaboration with the University of Bristol, Southampton and the Hull York Medical School. It is funded by The NHS National Institute for Health Research (NIHR) HTA. The study is also supported by the NIHR Clinical Research Networks.

Who has reviewed the study?

The study is funded by the National Institute for Health Research (NIHR) after peer review. The study has been given a favourable opinion by the NRES Committee: Cambridge South Research Ethics Committee.


All information will be held securely and in strict confidence.  We keep the information we collect about the participant separately from their  personal details and we can only link this information together with a secure code. Only authorised members of the research team will have access to their information.  

The research team will occasionally need to allow monitors from Regulatory Authorities to inspect the trial paperwork, in order to meet legal, ethical and safety requirements. All individuals who have access to data will be bound by strict data protection and confidentiality rules. Participants will not be identifiable in any published report from this study.