Condition category
Mental and Behavioural Disorders
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Nightmares are disturbing dreams which leave an individual feeling distressed when they wake up. Nightmares are a common experience for people who have persecutory fears or hear voices (symptoms of psychosis*). However, despite being distressing, they are rarely the focus of treatment. Previous research with people without psychosis has shown that nightmares can be reduced through offering cognitive behavioural (talking) therapy (CBT), specifically targeting nightmares. The key technique in this therapy is called Imagery Rehearsal and involves practicing an alternative and less distressing ending to the original nightmare ‘script’. However, people experiencing symptoms of psychosis have typically been excluded from these studies and hence we do not know if the therapy is effective for this group. The aim of this study is to find out whether CBT for nightmares is acceptable and feasible to offer to people who experience persecutory fears. The study will also look into whether the therapy improves nightmares as well as mood, fears, emotional wellbeing and other distressing or unusual experiences.

*Psychosis describes a range of symptoms such as hearing voices or experiencing fears of being harmed/persecuted by other people. In their most severe form, fears of other people are described as persecutory delusions.

Who can participate?
Adult patients who experience regular nightmares, persistent persecutory delusions and have a diagnosis of non-affective (not related to disturbance of mood) psychosis (e.g. schizophrenia).

What does the study involve?
Participants are randomly allocated to one of two groups. Those in the first group are given individual sessions of CBT for nightmares over the course of 4 weeks, in addition to all of their standard NHS care. The length of these sessions and how many they have are decided based on the individual patients’ needs. Those in the second group continue with all their standard NHS care alone throughout the course of the study, however they are offered the full CBT for nightmares therapy at the end of the study. Participants complete a range of questionnaires and interview assessments at the start of the study, and then again at 4 and 8 weeks. Participants who receive the CBT for nightmares immediately will be invited to take part in an interview to find out about their experience of nightmares, the therapy and any changes they’ve noticed over the 8 weeks of the study.

What are the possible benefits and risks of participating?
Participants may benefit from a decrease in the frequency of their nightmares as a results of the CBT. There are no known risks of taking part in the study.

Where is the study run from?
Oxford Health NHS Foundation Trust (UK)

When is the study starting and how long is it expected to run for?
November 2015 to October 2016

Who is funding the study?
Wellcome Trust (UK)

Who is the main contact?
Dr Bryony Sheaves

Trial website

Contact information



Primary contact

Dr Bryony Sheaves


Contact details

Department of Psychiatry
Warneford Hospital
Warneford Lane
United Kingdom
+44 1865 226486

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The Nightmare Intervention Study: A pilot randomised controlled trial of a brief cognitive behavioural therapy for nightmares for patients with persecutory delusions



Study hypothesis

The aim of this study is to assess the acceptability and feasibility of cognitive behavioural therapy for nightmares, delivered to patients experiencing persecutory delusions.

Ethics approval

South Central – Oxford C Research Ethics Committee, 29/09/2015, ref: 15/SC/0502

Study design

Randomised; Interventional; Design type: Treatment

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


Topic: Mental Health; Subtopic: Psychosis; Disease: Psychosis


Participants will be randomly allocated to one of two groups.

Group 1: Participants will receive individual sessions of CBT for nightmares, delivered over a period of four weeks. The length and number of therapy sessions will be decided based upon patient choice and clinical need. The key therapy techniques will include Imagery Rehearsal training (re-scripting the content of the nightmare) and techniques to better manage nightmare related distress (for example compassion and grounding techniques). All participants in this group will continue with all standard NHS care.

Group 2: This control group will not receive any CBT sessions over the 8 week course of the study, but will continue with all standard NHS care. The CBT for nightmares therapy will then be delivered to these participants at the end of the study.

All participants will complete questionnaire assessments of nightmares, sleep and other daytime psychiatric symptoms. These will be at 0 weeks (baseline), 4 weeks (end of therapy) and 8 weeks (follow up). All participants in the immediate intervention group will be invited to complete a qualitative interview to find out more about their experience of nightmares, of the therapy and any changes they notice over the eight week therapy period.

Intervention type



Drug names

Primary outcome measures

1. To assess trial methodology including the acceptability and feasibility of the intervention and recruitment and retention rates. This will be measured by the number of sessions used, uptake of therapy, sessions required, participant satisfaction and trial dropout rates.
2. Nightmare severity will be measured using the Distressing Dreams and Nightmare Severity Index measured at baseline, 4 and 8 weeks

Secondary outcome measures

1. Psychological wellbeing will be measured using the Warwick Edinburgh Mental Wellbeing Scale measured at baseline, 4 and 8 weeks
2. Persecutory beliefs will be measured using the Green Paranoid Thoughts Scale at baseline, 4 and 8 weeks
3. Hallucinatory experiences will be measured using the Cardiff Anomalous Perceptions Scale at baseline, 4 and 8 weeks
4. Affect will be measured using the Depression Anxiety and Stress Scale - 21 item version measured at baseline, 4 and 8 weeks
5. Symptoms of insomnia will be measured using the Sleep Condition Indicator at baseline, 4 and 8 weeks
6. Sleep quality will be measured using the Pittsburgh Sleep Quality Index measured at baseline, 4 and 8 weeks
7. Dissociative symptoms will be measured using the Brief Dissociative Experiences Scale at baseline, 4 and 8 weeks

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Currently experiencing one or more nightmares per week
2. A current persecutory delusion, as defined by Freeman and Garety (2000)
3. A cut off of 33 or above on part A or B on the Green Paranoid Thoughts Scale (Green et al., 2008).
4. Nightmares are at least moderately distressing (on a 7 point Likert scale, scoring at least 4).
5. Nightmares have been present for at least three months (i.e. chronic).
6. Aged between 18 and ­65 years
7. A clinical diagnosis of non­-affective psychosis (schizophrenia, schizo­affective disorder, delusional disorder or psychosis not otherwise specified)
8. Stable medication (both drug and dose) for at least four weeks and no planned medication changes. Where medication changes are planned, the patient will wait until medication has been stable before entering the trial.

Participant type


Age group




Target number of participants

Planned Sample Size: 24; UK Sample Size: 24

Participant exclusion criteria

1. Screen positive for sleep apnoea with no history of having received a full assessment and / or treatment. If receiving optimal treatment for sleep apnoea, the patient will be invited to take part.
2. Primary diagnosis of personality disorder, alcohol or substance dependency
3. An organic syndrome or learning disability
4. A command of spoken English inadequate for completing questionnaire measures, or engaging in therapy
5. Currently receiving cognitive behavioural therapy or due to commence within the time frame of the trial
6. Nightmares that are considered to be a side effect of medication by the treating psychiatrist

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Warneford Hospital
Department of Psychiatry Warneford Lane
United Kingdom

Sponsor information


University of Oxford

Sponsor details

Clinical Trials and Research Governance
Joint Research Office
Block 60 Churchill Hospital
United Kingdom

Sponsor type




Funder type


Funder name

Wellcome Trust

Alternative name(s)

Funding Body Type

private sector organisation

Funding Body Subtype



United Kingdom

Results and Publications

Publication and dissemination plan

Planned submission of an outcome paper to a peer reviewed journal within six months of the trial end date.

Intention to publish date


Participant level data

Not expected to be available

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes