Condition category
Mental and Behavioural Disorders
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Depression is one of the most common mental disorders worldwide. The symptoms of depression can vary greatly from person to person, but generally include low mood, problems with sleeping and/or eating, and a general loss of interest in life. Treatment for depression often relies heavily on antidepressant medications. It is thought that antidepressants work by increasing the levels of certain chemicals in the brain called neurotransmitters. 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. The aim of this study is to evaluate the effectiveness of long-term maintenance treatment for depression in the UK.

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?
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. Those in the second group take half the dose of their current medication for four weeks, and then take a dummy pill (placebo) for the remainder of the study. At the start of the study and then at 12, 26, 39 and 52 weeks, all participants complete a number of questionnaires to find out if there have been any changes in their mood.

What are the possible benefits and risks of participating?
Not provided at time of registration

Where is the study run from?
University College London (UK)

When is the study starting and how long is it expected to run for?
August 2015 to July 2019

Who is funding the study?
National Institute for Health Research (UK)

Who is the main contact?
Mrs Larisa Duffy

Trial website

Contact information



Primary contact

Mrs Larisa Duffy


Contact details

UCL Division of Psychiatry
6th Floor
Maple House
149 Tottenham Court Road
United Kingdom
+44 (0)20 7679 9282

Additional identifiers

EudraCT number

2015-004210-26 number

Protocol/serial number

HTA 13/115/48; 14/0647

Study information

Scientific title

A Phase IV double blind multi-site, individually randomised parallel group controlled trial investigating the use of citalopram, sertraline, fluoxetine and mirtazapine in preventing relapse in patients in primary care who are taking long term maintenance antidepressants but now feel well enough to consider stopping medication



Study hypothesis

Maintenance antidepressants reduce the rate of relapse in people who have recovered from depression and have been taking maintenance antidepressants for 9 months.

More details can be found at:

Ethics approval

East of England - Cambridge South Research Ethics Committee, 29/03/2016, REC ref: 16/EE/0032

Study design

Phase IV double-blind multi-site randomised parallel-group controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet




At baseline participants will be taking either citalopram (20mg), sertraline (100mg), fluoxetine (20mg) or mirtazapine (30mg). They will be randomised into one of two groups:

Control Group: Those in the control group remain on their current medication throughout the study period.

Intervention Group: Those in the intervention group take half the dose of their current medication for a period of four weeks (citalopram 10mg, sertraline, 50mg, fluoxetine 10mg or mirtazapine 15mg), and take a placebo for the remainder of the study period. All medications are given in Pill form.

Intervention type



Phase IV

Drug names

1. Citalopram
2. Sertraline
3. Fluoxetine
4. Mirtazapine

Primary outcome measures

Time to depressive relapse measured using the modified shortened clinical interview schedule-revised (CIS-R) at baseline, 12 weeks, 26 weeks, 39 weeks and 52 weeks.

Secondary outcome measures

1. Depressive symptoms will be measured using the PHQ9 at baseline, 12 weeks, 26 weeks, 39 weeks, 52 weeks
2. Anxiety symptoms will be measured using the GAD7 questionnaire at baseline, 12 weeks, 26 weeks, 39 weeks, 52 weeks
3. Quality of life will be measured using the EQ5D-5L questionnaire for quality adjusted life years (QALYs) at baseline, 12 weeks, 26 weeks, 39 weeks, 52 weeks
4. Adverse effects of antidepressants will be measured using a modified Toronto Side Effects scale at baseline, 12 weeks, 26 weeks, 39 weeks, 52 weeks
5. Adherence to study medication will be measured using the modified Morisky scale at baseline, 12 weeks, 26 weeks, 39 weeks, 52 weeks
6. Quality of life will be measured using the Health related quality of life questionnaire (SF12) at baseline, 12 weeks, 26 weeks, 39 weeks, 52 weeks

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Aged between 18 and 74 years
2. Have experienced at least two episodes of depression
3. Have been taking antidepressants for at least 9 months (citalopram 20mg, sertraline 100mg, fluoxetine 20mg or mirtazapine 30mg)
4. Be well enough to consider stopping their antidepressant medication

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Meet internationally agreed (ICD10) criteria for a depressive illness
2. Score above 10 on the depressive symptom questionnaire (PHQ9)
3. Have bipolar disorder, psychotic illness, dementia or a terminal illness
4. Are not able to complete self-administered questionnaires in English
5. Have contraindications for any of the prescribed medication

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University College London
149 Maple House Tottenham Court Road
United Kingdom

Sponsor information



Sponsor details

UCL Medical School
Upper 3rd Floor
Royal Free Campus
Rowland Hill Street
United Kingdom
+44 (0)20 7794 0500 ext 36724

Sponsor type




Funder type


Funder name

Health Technology Assessment Programme

Alternative name(s)

NIHR Health Technology Assessment Programme, HTA

Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government


United Kingdom

Results and Publications

Publication and dissemination plan

Not provided at time of registration.

Intention to publish date


Participant level data

To be made available at a later date

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes

31/03/2016: Ethics approval information added.