Secondary outcome measures
Self-esteem is measured using the Roseneberg Self-Esteem Scale [
18] which contains ten items measured on a four-point scale. The scale measures state self-esteem by asking the patient to reflect on their current feelings.
Psychotic Symptoms are assessed using two measures. The Positive and Negative Syndrome Scale (PANSS) [
19] includes scales of positive symptoms, negative symptoms and general psychopathology and is used widely in schizophrenia research. Also, the Psychotic Symptom Rating Scale (PSYRATS) [
16] is used to provide detailed information on the clinical characteristics of hallucinations and delusions, including distress and impact on functioning.
Anxiety is measured using the Generalised Anxiety Disorder Assessment (GAD7) [
20] which includes seven items each describing anxiety symptoms, and endorsed on the basis of frequency. Functioning is measured using the Work and Social Adjustment scale [
21]. Patient well-being is assessed using the Warwick-Edinburgh Mental Well-being Scale [
22], a fourteen-item questionnaire which includes both hedonic and eudaimonic features which are rated on a five-point scale.
A semi-structured interview will be developed in consultation with service-user focus groups to explore the acceptability of the intervention. All participants who are allocated to the Positive Memory Training group will be invited to participate in an interview.
Patients’ health-related quality of life will be measured by the EuroQol EQ-5D [
23], a generic, multi-attribute utility scale widely used for economic evaluations. In addition, patients will complete the ICECAP-A [
24] and OxCAP-MH [
25] instruments , both based on Sen’s capability approach that considers a broad concept of wellbeing including an individual’s ability to ‘do’ and ‘be’ the things that are important in life [
26].
Primary informal carers will complete the EuroQol EQ-5D [
23] and the Carer Experience Scale [
27] via postal questionnaire to measure separately the likely impacts of PoMET on carers’ quality of life and wellbeing.
Costs will be assessed from a broad societal perspective using an amended version of the Client Service Receipt Inventory [
28] and therapists’ records. These will include information on all PoMET treatment related costs, other health care resource use costs (including in-patient stays, outpatient visits, community mental health service contacts, primary care contacts, and medications), social care costs, and broader societal impacts (including costs to the patients and their families and lost productivity costs). Costs will be calculated using UK national-level unit costs.
Assessments will be conducted at baseline, 3-months (end of treatment) and at 6-months and 9-months after randomisation. All measures will be completed at baseline, 3-month and 9-month assessment. The 6-month assessment includes only measures of depression, patient health status (including quality of life and wellbeing) and costs.