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

Plain English Summary

Background and study aims
Psychosis and schizophrenia are common and costly mental health problems. Psychosis is the name given to a group of mental conditions in which cause people to perceive or interpret things differently from those around them. One of the most common causes of psychosis is schizophrenia, a condition that causes a range of psychological symptoms, including hallucinations (hearing and/or seeing things) and delusions (believing something that is not true). One of the main treatment options for psychosis and schizophrenia is long-term treatment with antipsychotic medication, but many patients still find life difficult. Antipsychotic drugs can also have dangerous and unpleasant side effects. Finding alternatives to long-term drug treatment is a priority for patients and services. This study is testing the effects of gradually reducing antipsychotic medication in people with schizophrenia, psychosis or similar conditions in order to see if it can help improve day-to-day functioning and how it affects their chance of suffering a relapse (worsening of their condition).

Who can participate?
Adults who have been diagnosed with schizophrenia, psychosis or a similar condition and are taking antipsychotic medication.

What does the study involve?
Once a person agrees to take part, they are randomly selected to receive either the ‘antipsychotic reduction programme’ or ‘maintenance treatment’. The ‘antipsychotic reduction programme’ involves reducing the participant’s dose of antipsychotic medication gradually over several months. Participants are seen regularly by a psychiatrist to review and adjust their antipsychotic medication and to monitor their mental health. Some participants are recommended to try and stop their antipsychotic medication. Other participants are supported to maintain as low a dose as possible. Participants who are selected for ‘maintenance treatment’ are recommended to stay on roughly the same dose of antipsychotics throughout the study. Small adjustments can be made as required to reduce side effects or for other reasons. All participants complete assessments at the start of the study and then again after 6, 12 and 24 months to assess their social functioning, symptoms and medication side effects. Some participants and clinicians involved in the study are also invited to be interviewed in more detail to explore how they found the antipsychotic reduction programme and their experience of being in the study.

What are the possible benefits and risks of participating?
As this is a trial of a new approach to antipsychotic treatment, it is not yet clear if participants will receive any direct benefit from taking part. Previous research suggests participants who receive support to reduce antipsychotics have improved social functioning, but it is not known whether this will be the case in the current study. Previous research has shown that some people may experience increased symptoms of psychosis or schizophrenia as their medication is lowered, and there may be an increased risk of having a relapse. Participants receiving the antipsychotic reduction programme will be monitored regularly to prevent this. If participants experience increased symptoms or relapse, they will be given additional treatment, as they would receive if they were having their usual care. The reduction of antipsychotic medication will be halted if necessary, and antipsychotics may be re-started if they have been stopped.

Where is the study run from?
1. North East London NHS Foundation Trust (UK)
2. East London NHS Foundation Trust (UK)
3. Camden and Islington NHS Foundation Trust (UK)
4. Barnet, Enfield & Haringey Mental Health Trust (UK)

When is the study starting and how long is it expected to run for?
January 2016 to January 2022

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

Who is the main contact?
Dr Nadia Crellin

Trial website

Contact information



Primary contact

Dr Nadia Crellin


Contact details

Research and Development
North East London NHS Foundation Trust
Maggie Lilley Suite
Goodmayes Hospital
Barley Lane
United Kingdom
+44 30 0555 1200 ext. 64488

Additional identifiers

EudraCT number

2016-000709-36 number

Protocol/serial number


Study information

Scientific title

Research into Antipsychotic Discontinuation and Reduction (RADAR): A Randomised Controlled Trial



Study hypothesis

The aim of this study is to compare a gradual strategy of antipsychotic reduction and possible discontinuation with maintenance (continuous) treatment in people with schizophrenia or who have recurrent psychotic episodes.

Ethics approval

London-Brent Research Ethics Committee, 27/10/2016, ref: 16/LO/1507

Study design

Randomised; Interventional; Design type: Treatment, Drug

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

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


Specialty: Mental Health, Primary sub-specialty: Psychosis - schizophrenia; UKCRC code/ Disease: Mental Health/ Schizophrenia, schizotypal and delusional disorders


Consenting participants are randomly allocated to one of two groups.

Control group: Participants continue to receive antipsychotic treatment at the original dose.

Intervention group: Participants take part in the Antipsychotic Reduction and Discontinuation strategy. This involves having their antipsychotic medication gradually reduced and discontinued if possible. The reduction is flexible, and can be done slowly or more quickly over approximately 12 months, depending on experiences or circumstances. During this time participants see their psychiatrist roughly every 2 months to discuss how they are getting on and to review their medication.

Participants are followed up at 6 months, 1 year, and 2 years and will include an assessment of social functioning, symptoms and medication side effects.

Intervention type



Phase IV

Drug names

Primary outcome measure

Social functioning is measured by the Social Functioning Scale at baseline, 6, 12 and 24 months.

Secondary outcome measures

1. Symptoms are measured by the Positive and Negative Syndrome Scale (PANSS) at baseline, 6, 12 and 24 months
2. Side effects as measured by the Modified Glasgow Antipsychotics Side-effects Scale (GASS) at baseline, 6, 12, and 24 months
3. Patient satisfaction as measured by the Client Satisfaction Questionnaire (CSQ 8) at baseline, 6, 12 and 24 months
4. Subjective quality of life as measured by the Manchester Short Assessment of quality of life (MANSA) at baseline, 6, 12 and 24 months
5. Neuropsychological function tests at baseline, 12 and 24 months
6. Medication adherence as measured by the Medication Adherence Rating Scale (MARS-5) at baseline, 6, 12 and 24 months
7. Relapse as measured by the relapse assessment schedule questionnaire at 6, 12 and 24 months
8. Health state as measured by the EQ-5D-5L at baseline, 6, 12 and 24 months
9. Wellbeing as measured by the ICECAP-A at baseline, 6, 12 and 24 months
10. Cost of health and social care as measured by the Client Service Receipt Inventory at baseline, 6, 12 and 24 months
11. Ability to work as measured by the Work Productivity and Activity Questionnaire at baseline, 6, 12 and 24 months
12. Economic data collected from patient records at baseline 12 and 24 months
13. Recovery as measured by the Questionnaire about the Process of Recovery (QPR) at baseline, 6, 12 and 24 months
14. Sexual experiences as measured by the Arizona Sexual Experiences Scale (ASEX) at baseline, 6, 12 and 24 months

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Aged over 18 years
2. A clinical and/or ICD10 diagnosis of schizophrenia, schizoaffective disorder, delusional disorder or other non-affective psychosis
3. More than one previous episode of relapse or psychotic exacerbation, or a single episode lasting more than one year
4. Taking antipsychotic medication

Participant type


Age group




Target number of participants

Planned Sample Size: 402; UK Sample Size: 402

Participant exclusion criteria

1. Participant lacks capacity to consent to the trial
2. Participant has insufficient command of spoken English to understand trial procedures
3. Participant subject to a Community Treatment Order (CTO) that includes a requirement to take antipsychotic medication
4. Clinician considers there will be a serious risk of harm to self or others
5. Participant has been admitted to hospital or had treatment from the Home Treatment or Crisis Team within the last month
6. Females who have a confirmed pregnancy
7. Females who are breast-feeding
8. Involvement in another IMP trial
9. No contraindications to continuing on antipsychotic medication

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

North East London NHS Foundation Trust
Research & Development Department 1st floor, Maggie Lilley Suite Goodmayes Hospital Barley Lane
United Kingdom

Trial participating centre

East London NHS Foundation Trust
Newham Centre for Mental Health
E13 8SP
United Kingdom

Trial participating centre

Camden and Islington NHS Foundation Trust
Bloomsbury Building St Pancras Hospital 4 St Pancras Way
United Kingdom

Trial participating centre

Barnet, Enfield and Haringey Mental Health Trust
St. Ann's Hospital St Ann's Road
N15 3TH
United Kingdom

Sponsor information


University College London

Sponsor details

Priment Clinical Trials Unit
Primary Care & Population Health
Royal Free Campus
Rowland Hill Street
United Kingdom
+44 20 7794 0500 Ext: 36724

Sponsor type




Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government


United Kingdom

Results and Publications

Publication and dissemination plan

Results will be written up for publication in high level scientific peer reviewed journals, and presented at academic conferences.

IPD sharing statement:
The current data sharing plans for the current study are unknown and will be made available at a later date.

Intention to publish date


Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

09/11/2017: The ISRCTN prospective/retrospective flag compares the date of registration with the recruitment start date and does not include any grace period. The registration of this study was requested through the NIHR Portfolio and was finalised within 6 months of the recruitment starting.