RADAR Trial: Testing the effects of reducing and discontinuing antipsychotic medication in people with long-term schizophrenia and similar conditions

ISRCTN	ISRCTN90298520
DOI	https://doi.org/10.1186/ISRCTN90298520
ClinicalTrials.gov (NCT)	NCT03559426
Clinical Trials Information System (CTIS)	2016-000709-36
Integrated Research Application System (IRAS)	193921
Protocol serial number	31486, IRAS 193921
Sponsors	University College London, North East London NHS Foundation Trust
Funder	National Institute for Health Research

Submission date: 30/01/2017
Registration date: 07/02/2017
Last edited: 02/10/2023

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Mental and Behavioural Disorders

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

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 March 2022

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

Who is the main contact?
Dr Nadia Crellin
nadia.crellin@nelft.nhs.uk

Contact information

Dr Maria Long
Scientific

Division of Psychiatry
University College London
Maple House
149 Tottenham Court Rd
London
W1T 7BN
United Kingdom

ORCID ID	0000-0002-6920-9676
Phone	+44 (0)7966616082
Email	Maria.long@nelft.nhs.uk

Study information

Primary study design	Interventional
Study design	Randomised; Interventional; Design type: Treatment, Drug
Secondary study design	Randomised controlled trial
Study type	Participant information sheet
Scientific title	Research into Antipsychotic Discontinuation and Reduction (RADAR): a randomised controlled trial
Study acronym	RADAR
Study objectives	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(s)	London-Brent Research Ethics Committee, 27/10/2016, ref: 16/LO/1507
Health condition(s) or problem(s) studied	Schizophrenia
Intervention	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	Drug
Phase	Not Applicable
Drug / device / biological / vaccine name(s)	Antipsychotic treatment
Primary outcome measure(s)	Social functioning is measured by the Social Functioning Scale at baseline, 6, 12 and 24 months Added 14/09/2022: Also measured between 48-84 months from randomisation into the original trial
Key secondary outcome measure(s)	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 Added 14/09/2022: All outcome measures except the social cognition battery will also be measured between 48-84 months from randomisation into the original trial
Completion date	10/03/2022

Eligibility

Participant type(s)	Patient
Age group	Adult
Lower age limit	18 Years
Sex	All
Target sample size at registration	218
Total final enrolment	253
Key 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
Key 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
Date of first enrolment	24/03/2017
Date of final enrolment	31/01/2020

Locations

Countries of recruitment

United Kingdom
England

Study participating centres

North East London NHS Foundation Trust

Research & Development Department
1st floor, Maggie Lilley Suite
Goodmayes Hospital
Barley Lane
Ilford
IG3 8XJ
United Kingdom

East London NHS Foundation Trust

Newham Centre for Mental Health
London
E13 8SP
United Kingdom

Camden and Islington NHS Foundation Trust

Bloomsbury Building
St Pancras Hospital
4 St Pancras Way
London
NW1 0PE
United Kingdom

Barnet, Enfield and Haringey Mental Health Trust

St. Ann's Hospital
St Ann's Road
London
N15 3TH
United Kingdom

Results and Publications

Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Data sharing statement to be made available at a later date
IPD sharing plan	The current data sharing plans for the current study are unknown and will be made available at a later date.

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article		28/09/2023	02/10/2023	Yes	No
Protocol article	protocol	27/11/2019	27/10/2020	Yes	No
HRA research summary			28/06/2023	No	No
Participant information sheet	Participant information sheet	11/11/2025	11/11/2025	No	Yes
Study website	Study website	11/11/2025	11/11/2025	No	Yes

Editorial Notes

02/10/2023: Publication reference added.
20/09/2022: The overall trial end date was changed from 30/06/2022 to 10/03/2022. ClinicalTrials.gov number added.
14/09/2022: The primary and secondary outcome measures were updated. North East London NHS Foundation Trust was added as a sponsor.
10/05/2022: The study contact has been updated.
24/01/2022: The following changes have been made:
1. The overall trial end date has been changed from 01/01/2022 to 30/06/2022 and the plain English summary has been updated accordingly.
2. The total final enrolment number has been added.
27/10/2020: Publication reference added.
19/02/2020: The following changes have been made:
1. The IRAS number has been added.
2. The scientific contact has been updated.
17/02/2020: The scientific contact has been updated.
18/09/2019: The target number of participants and total target enrolment were updated from 402 to 218.
27/08/2019: The recruitment end date was updated from 01/08/2019 to 31/01/2020.
10/04/2019: The recruitment start date was changed from 01/02/2017 to 24/03/2017.
28/03/2019: The condition has been changed from "Specialty: Mental Health, Primary sub-specialty: Psychosis - schizophrenia; UKCRC code/ Disease: Mental Health/ Schizophrenia, schizotypal and delusional disorders" to "Schizophrenia" following a request from the NIHR.
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.