This feasibility study was reported according to the CONSORT 2010 guidelines for randomised pilot and feasibility trials18. The full trial protocol detailing study design and methods has been published17 and is summarised below.
Trial Design
A feasibility study with a two-arm randomised parallel controlled trial conducted in two UK centres: Berkshire Healthcare NHS Foundation Trust (BHFT) and Oxford Health NHS Foundation Trust (OHFT) (combined as one site) and Devon Partnership NHS Trust (DPT). The study was approved by the NHS Research Ethics Committee (reference 18/SC/0164). The study aimed to recruit 60 participants randomly allocated 1:1 to an intervention plus treatment as usual (IBER + TAU group) or TAU alone (TAU group).
Participants
Referrals were accepted from in-patient services, primary and secondary care and self-referral. Referrals were sought from people aged 18 or above who presented with symptoms consistent with a DSM-V diagnosis of bipolar disorder (I, II or otherwise specified) assessed using the Structured Clinical Interview for DSM-5 (SCID) 19,20. Potential participants were required to have a sufficient understanding of English in order to be able to engage in the study, and to exhibit at least a mild level of anxiety by scoring 5 or above on the GAD-7 21. Exclusion criteria were (i) a current episode of mania or depression (ii) unable to provide informed consent (iii) acute suicide risk (iv) DSM-5 diagnosis of substance use or alcohol use disorder, moderate or severe, assessed using the SCID (v) a change in medication within 3-months prior to randomisation or (vi) currently engaged in a psychological intervention.
Randomisation and blinding
Randomisation was stratified by trial site and minimised on medication status (in receipt of prescribed mood stabilisers vs. not) and anxiety severity (GAD-7 > 14 [severe anxiety] vs GAD-7 ≤ 14). Web-based randomisation was conducted independently, by the Thames Valley Clinical Trials Unit (TVCTU), using randomised permuted blocks.
Group allocation was transparent to the participant, trial manager and trial therapists whilst the researchers responsible for collecting assessment data remained blind to group allocation. The trial adhered to procedures designed to maintain separation between research staff who obtained measures and clinical staff who delivered the intervention. This included the use of separate offices, separate booking systems when seeing participants and separate agendas within team meetings. As all follow-up assessments were done online or via post, blind-breaks did not occur during assessments. Where an allocation was revealed to an assessor at any point during the study, masking was maintained through a new assessor being the point of contact thereafter.
Interventions
Imagery Based Emotion Regulation (IBER) is a structured individual psychological intervention consisting of up to 12 sessions to be delivered within 16 weeks. The intervention targets maladaptive mental imagery. An in-depth assessment phase leads to the identification of a target image or images co-identified and formulated by the client and therapist as impacting on anxiety and mood instability. In the active treatment phase visual imagery techniques are applied to the formulated target. The final skills consolidation phase aims to embed strategies in a memorable format for clients to access easily in future. IBER was informed by, though not the same as, the manual we have developed on the basis of our previous work 15,16,22. Further details of the three stages are given below:
Assessment
This stage occurs over 4 sessions and includes assessment of current positive coping strategies, ability to recognise prodromes of mood episodes and, where necessary, the development of a crisis management plan. This is followed by the identification of current emotional mental images impacting on anxiety and mood instability, and the creation of an individualised formulation which includes imagery-related beliefs and responses.
Treatment
Four theoretically informed mental imagery-based interventions have been developed as detailed below. The individual formulation created in the assessment phase maps out images to target in the intervention, and the individual treatment approach follows from this.
Typical images worked on in therapy included intrusive images related to the client’s bipolar disorder, for example, images of being very depressed. Often these were associated with a sense of fear and hopelessness and the meaning “I will end up feeling like that again and won’t be able to cope”. Clients also frequently worked on modifying anxious images about the future, including distorted images of themselves and others in social situations. These images had underlying meanings such as: “I am not like other people”, “I am not accepted”.
Imagery-based intervention techniques are used in isolation or in combination.
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Imagery Rescripting (IR) involves assisting people to transform maladaptive or distressing imagery into more functional, benign imagery, thereby updating its underlying meaning. Although adapted from the approach with the same name used for treating traumatic memories 23, here IR was not limited to working with memories but also to modify simulated images of the future. IR is typically adopted when the participant is mainly troubled by one or two repetitive images.
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Metacognitive Techniques aim to reduce the “power” of an image by changing how a client relates to the image. The strategies reinforce an image is “just an image” and not real. Thus, the client does not need to pay attention to the image. Instead, they should direct their attention outside of the image. Such strategies are used with the majority of participants in combination with other techniques.
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Positive Imagery Techniques help participants to generate mood-enhancing or soothing imagery which holds a helpful and adaptive meaning for the client. Imagery of this type is frequently lacking in clients with BD. Positive imagery may be used to induce a sense of well-being, act to bolster self-esteem, or encourage the client to move in the direction of desired goals.
(iv) Imagery-competing Tasks implement concurrent visuospatial activities (such as the computer game Tetris) to reduce the intensity and/or recurrence of problematic imagery. This approach has been used in studies aimed at reducing the frequency of traumatic intrusions 24, however in IBER these techniques were mainly used to reduce the impact of images (for example at night when imagery was disrupting sleep) and were always used in combination with one or more of the other imagery techniques detailed.
Skills consolidation
skills that have been learnt during treatment are consolidated into an action-plan that the participant can implement This is documented as a personal video designed by the client which captures the action-plan in video film images in addition to words.
The intervention was delivered by four clinicians; all clinical psychologists experienced in using CBT. Training consisted of a two-day programme, and supervision was provided by team members (SH, KY) with relevant expertise both in the intervention and the patient group. Sessions were recorded where the patient gave consent. Adherence to treatment protocol was monitored through the use of a bespoke measure developed by the trial team. The measure consisted of a checklist tailored for each phase of the IBER treatment. Ratings were made for both specific items necessary for the particular phase of treatment (e.g. “helps the client elucidate imagery or other co-morbidities impacting on anxiety”) and general competencies (e.g. “therapist displays a curious stance”). Ratings were made on a 4-point Likert scale from 0 (not adherent) to 3 (good quality and adherent). If an item was rated 2 or above this indicated that the work was of good enough quality to be adherent. Random sessions recorded from 20% of treatment cases were assessed for adherence by an external rater who was an expert in the intervention.
Both groups received TAU which was delivered by mental health professionals from within the NHS Trusts and was based on local protocols. All treatment was recorded as part of the amended Client Service Receipt Inventory25 used for the collection of health and social care data and typically included medication and contact with psychiatrists and community psychiatric nurses, while information on the IBER intervention was recorded as part of the trial therapist diaries.
Outcome assessment
Assessments were conducted by graduate psychologists at baseline (prior to randomisation), 16-weeks (end of treatment) and 32-weeks follow up post-randomisation through self-report questionnaires, completed predominantly via a secure online questionnaire system (ePRO®, P1vital Products Ltd.). A small number (n = 3) of participants completed paper questionnaires which were returned by post. Potential participants must have completed all baseline assessments, and at least 23 out of the 28 daily mood monitoring measurements conducted prior to baseline (see below) in order to meet inclusion eligibility
The primary outcome was anxiety as measured by the GAD-721 at end of treatment. Secondary outcomes were depression, as measured by Quick Inventory of Depressive Symptomatology–Self Report (QIDS-SR)26, and mania as measured by the Altman Self-Rating Scale for Mania (ASRM)27. Each of these three outcomes (anxiety, depression and mania) were measured by administering self-report questionnaires on four separate occasions - one week apart - covering a 28-day period, with the mean value captured as the reference point. Baseline data covered the 28-days prior to randomisation, and follow-up data covered the 28-days after each follow-up assessment due date (i.e. starting at 16-weeks and 32-weeks post randomisation).
Mood stability was measured by participants rating (0–6) how anxious, elated, sad and angry they felt on a daily basis over the same 28-day period at baseline, end of treatment and follow-up 28.
Patients’ health-related quality of life was measured by the EuroQol EQ-5D-5L29, whilst general wellbeing was measured by the ICECAP-A30 and OxCAP-MH31 instruments. Health care resource and costs were measured using the Health Economics Questionnaire (HEQ)25. All health-related measures were collected every 28-days from the start of the trial, until the follow-up assessment.
All serious adverse events were documented throughout the trial and reported to the Data Monitoring and Ethics Committee, where the independent chair determined whether the event was attributed to the delivery of the intervention. Non-serious adverse events were also recorded.
After trial completion all participants were posted a questionnaire to assess their experiences of both the trial procedures and intervention. A sub-sample of those allocated to the intervention were invited to take part in an in-depth interview to discuss their experiences of IBER treatment.
Data Analysis
The sample size of 60 participants was sufficient to achieve the feasibility objectives. The data analysis was presented on a descriptive level. The study reports recruitment, study attrition, and intervention (IBER + TAU) completion (≥ 50% of sessions attended) and completion of outcome, where appropriate with 95% confidence intervals. Mean and standard deviations for all outcomes are reported for both study arms at baseline, 16 and 32 weeks, between group differences and 95% CIs reported.
Mood variability is quantified using the standard deviation Root Mean Squared Successive Differences27 for each of the four daily mood measures items.
Feasibility criteria for a full trial assessed during this study (as published in the protocol paper17) were (i) overall recruitment at ≥ 80% or above within the 12-month recruitment period i.e. ≥48 participants recruited (ii) 32-week follow-up data from ≥ 80% of participants on all outcomes (iii) ≥ 80% of participants attend at least 50% of the possible sessions) (iv) no serious negative consequences (serious adverse events) associated with trial or intervention participation.