The design is a single-blind, multicentre, pilot RCT of CBT plus treatment as usual (TAU) versus TAU for people with dementia. Patient-carer dyads will be randomly allocated to either CBT or TAU. As no trials have been done in this area, we were unable to estimate the likely effect size of this intervention. We will recruit 50 participants with power set at 80%, p = 0.05. This will be adequate to detect an effect size of 0.8 or above. An objective of this study is to provide data on the actual effect size of the intervention in order to do a power analysis for a definitive RCT. Figure 1 shows the trial design.

Fifty participants and their carers will be recruited through North East London Foundation Trust (NELFT) and North Essex Partnership NHS Foundation Trust (NEPFT). Recruitment will be through memory services, community mental health teams, admiral nursing teams and outpatient referrals.

Inclusion criteria are:

1. Meet DSM-IV criteria for dementia in mild to moderate range, Clinical Dementia Rating (CDR) 23 score of 0.5, 1 or 2.

2. Clinical anxiety, as determined by a score of 11 or above on the Rating Anxiety in Dementia scale (RAID) 24 .

3. Living in the community.

4. The presence of a carer who is willing to participate in the therapy.

5. An ability to understand and communicate in English.

6. Willing to engage in therapy involving discussion of thoughts and feelings.

Exclusion criteria are:

1. Co-morbid psychiatric disorder (e.g. psychosis) or challenging behaviour (e.g. severe agitation) likely to prevent engagement in therapy.

2. Presence of a learning disability or severe physical illness that could impact on participation.

Ethical approval was obtained through the East London 3 Research Ethics Committee (ref. no. 10/H0701/124). Informed consent will be sought from participants and their carers, using current guidance from the British Psychological Society on evaluation of capacity. Participants may withdraw from the trial at any time without giving a reason. The withdrawal of the participant from the trial will not affect their access to other appropriate treatments or services.

All information disclosed in the study will be kept confidential, and participants will not be identifiable in any material published as part of the study in any way. All data are stored without any identifying details under secure conditions and all tapes will be destroyed at the end of the trial. In line with Standard Operating Procedures for the study, the reporting of Serious Adverse Events will be made to the Chief Investigator. The Chief Investigator will then inform the Research & Development Manager and Trust Governance Manager. Local policy and procedures will be followed for reporting and investigating serious untoward incidents.

Randomisation will be conducted by telephoning an independent administrator within PRIMENT Clinical Trials Unit after the participant/carer has provided informed consent and baseline data. The randomisation schedule is being developed by an independent statistician in PRIMENT, and blocking will be employed (with block sizes varying between 4 and 6) to help ensure equal numbers in the intervention and control arms.

CBT plus TAU: The patient-carer dyads will participate in 10 weekly sessions, each lasting 1 h hour. This number was determined on the basis of the published literature, the team’s experience and patient and carer feedback.

The manual is divided into four phases. Phase 1 involves assessment and formulation. Key aims are to build a collaborative relationship, socialisation to the CBT model, identifying goals and establishing the involvement of the carer. The carer’s role is to support the person with dementia in implementing strategies, for example applying what has been discussed during sessions in everyday life. Their involvement could range from very little (e.g. attending brief parts of some sessions) to being present at all times. Phase 2 involves the application of change processes, which the therapist will adapt according to the needs and strengths of the individual. These include identifying and practicing strategies for feeling safe, identifying and challenging unhelpful cognitions, ‘realistic negative automatic thoughts’, calming thoughts (on cue cards) and behavioural experiments. Phase 3 works on ending the therapy and developing a blueprint for the future. This includes reviewing and consolidating learned skills, integration of skills into everyday life and considering the future involvement of carers and others.

Sessions will cover themes and broad ideas, but there will be specific guidelines on how to adapt them to suit the needs of individuals. For example, the degree to which ‘cognitive’ and ‘behavioural’ elements are used will vary, with higher functioning participants being more able to access the ‘cognitive’ and a greater emphasis on behavioural aspects with the more impaired.

For some, sessions may need to be shortened or breaks may be required to maximise attention.

Telephone contact will be offered between sessions to answer questions and encourage ongoing work, should it be required. Sessions will be delivered by clinical or counselling psychologists, with experience of working with people with dementia. They will be given regular clinical supervision by a senior old age clinical psychologist with specialist CBT training.

Treatment as usual (TAU): This is defined as the standard treatment available to people with anxiety and dementia, which is most likely to include medication or no treatment.

All outcome measures will be administered by the main research assistant, blind to group allocation, at week 1 (baseline), week 15 (follow-up 1) and 6 months (follow-up 2). Fifteen weeks for follow-up 1 was determined by the field-testing phase, which suggested that it takes an average of 15 weeks to complete a ten-session intervention because of factors such as randomisation time, illness and holiday. Demographics and general information will be collected including age, gender, ethnic group, use of medication (including anxiolytics and cholinesterase inhibitors), treatment preference and participation in other activities. The Clinical Dementia Rating (CDR) 23 will be used to provide a global rating of dementia severity as part of the general background information.

1. Rating Anxiety in Dementia (RAID) 24 . This rates signs and symptoms of anxiety using interviews with carers and people with dementia. There are 18 questions in four categories: worry, apprehension, vigilance, motor tension and autonomic hypersensitivity. A score of 11 or above indicates significant clinical anxiety. It has good inter-rater and test-retest reliability, is sensitive to change and correlates with quality of life 25 .

2. Clinical Services Receipt Inventory (CSRI) 26 . A tool that collects information about the interviewee’s use of health and social care services, accommodation and living situations, income, employment and benefits, and any changes that may be incurred in the receipt of these services (after the therapy).

3. Mood: Hospital Anxiety and Depression Scale (HADS) 27 . The HADS is a widely used measure of anxiety and depression validated for all age groups.

4. Quality of life (QOL): Quality of Life-Alzheimer’s Disease (QOL-AD) 28 . This is a self-report measure for the person and their carer, with 13 items covering domains including physical health, energy, friends and fun. It has excellent inter-rater reliability and internal consistency, and good content, criterion and construct validity.

5. Behavioural disturbance: Neuropsychiatric Inventory (NPI) 29 . This assesses ten areas including delusions, hallucinations, dysphoria and agitation/aggression. Content and concurrent validity, inter-rater and test-retest reliability and internal consistency are all good.

6. Cognitive function: Mini-Mental State Examination (MMSE) 30 . This is an internationally recognised, 11-item set of simple tasks presented to the participant including orientation to time and place, attention, recall, language and visual construction. It has a maximum score of 30 points, with 24 or less suggesting cognitive impairment. Reliability and validity are satisfactory.

7. Depression: Cornell Scale for Depression in Dementia 31 . This rates depression in five categories including mood-related signs, behavioural disturbance and ideational disturbance, using information from interviews with staff and participants. Good reliability and validity have been demonstrated.

8. Personcarer relationship: Quality of Caregiver and Patient Relationship (QCPR) 32 . This is a 14-item scale measuring relationship quality including the level of criticism and level of warmth, rated by both the person and their carer. Good reliability and validity have been demonstrated.

9. Carer mood: Hospital Anxiety and Depression Scale (HADS) 27 .

After follow-up 1, 12 patient-carer dyads who received CBT will be invited to take part in qualitative interviews, led by another research assistant (to ensure blindness to treatment) and lasting approximately 1 hour. Issues addressed will include experiences of the sessions, views on themes and techniques, and benefits/changes identified in everyday life. Interviews will be audio recorded and transcribed. Framework analysis 33 will be used to extract themes and draw conclusions.

Treatment implementation (TI) strategies are recommended to ensure that treatment has been delivered, received and enacted as intended 34 . We will employ several methods to monitor treatment delivery and receipt: (1) the training and manual; (2) an adherence checklist devised in the manual, developed for the purpose of the study; (3) by audio recording all sessions, of which a random sample will be checked by GC for adherence to the manual. Treatment receipt and enactment will also be explored through qualitative interviews.

As this is a pilot trial, our main aims in evaluation will be to record response to recruitment, acceptability of randomisation, retention in therapy, attrition, prescribing of anxiolytics, any negative effects, extent/distribution of missing data and basic costs. We will conduct exploratory statistical analyses as our sample size will limit definitive conclusions. Data will be analysed by SPSSv16 using 'intention to treat'. Differences in outcomes between the two arms of the RCT over time will be modelled using generalised estimating equations, taking into account potential clustering due to using several therapists. We will also conduct exploratory analyses of factors predicting treatment outcome such as anxiolytic medication, age, dementia severity, treatment preference and number of sessions received. The confidence intervals around the effect size for the primary outcome, anxiety, will help us to estimate the sample size required for a full-scale trial.