EDEN-RCT study will employ a multicenter mixed-methods design using a connected phases approach, combining a randomized controlled trial for the quantitative component with an Interpretative Phenomenological Analysis (IPA) study for the qualitative component.
The study will be conducted over a period of 44 months, including 24 months of participant recruitment and 21 months of follow-up (± 30 days).
Participants recruitment:
Recruitment will be conducted among the active patient populations receiving care within the clinical departments of the eight centers participating in the study.
All healthcare professionals working in each participating center will be informed of the study initiation and its general procedures, namely the comparison of EDEN College with Care-as-usual (CAU) group interventions. These professionals may provide the study information sheet to adult voice-hearers and refer interested individuals to an appointment with one of the study investigators. A minimum period of 24 hours will be respected between the provision of the information sheet and the appointment with the investigator.
During the month preceding study initiation, posters will be displayed at the study sites and within their affiliated hospitals. These posters will invite adult voice-hearers to contact their healthcare professionals or the center investigators for further information about the study. Individuals who identify themselves as adult voice-hearers will be provided with the study information sheet and offered an appointment with one of the study investigators. A minimum period of 24 hours will be respected between the provision of the information sheet and the appointment with the investigator.
Method:
The single-blind randomized controlled trial (1:1 allocation ratio) will compare the effects of the EDEN College course with those of groups routinely provided in standard care that offer an equivalent number of intervention hours over the same time period. Conducting the study across eight centers in France will enable assessment of whether the effectiveness of the EDEN College intervention is independent of the facilitators delivering it.
Assessment of outcome measures at baseline (T1), post-intervention (T2), and 12 months after completion of the intervention (T3) will allow evaluation of both the effectiveness of the EDEN College course and the sustainability of their effects over time.
The primary analysis will be conducted according to the intention-to-treat principle using a random-effects linear mixed model to account for the repeated-measures structure of the data (pre- intervention, post-intervention assessments) and the comparison between the two study groups (EDEN and CAU). Fixed effects will include intervention group, assessment time point, and the group × time interaction. Recruitment centre will be included as a random effect to account for within-centre correlation and to allow for differences in mean outcome levels across centers. The model will be adjusted for relevant covariates identified a priori, including age, sex, and diagnosis.
The primary intervention effect will be assessed by comparing pre-intervention (T1) and post-intervention (T2 = T1 + 9 months) outcomes and will be estimated from the coefficient of the group × time interaction term.
The impact of the intervention on secondary outcomes at T2 and T3 will be evaluated using the same modelling approach. Given the number of questionnaires administered, secondary outcomes will be prioritised according to their relative importance and, where appropriate, adjustments for multiple comparisons will be applied using the Holm correction procedure.
The qualitative component will adhere to the methodological standards of Interpretative Phenomenological Analysis (Smith et al., 2021). Particular attention will be paid to participants' lived experiences and the meanings they attribute to them. These data will contribute to a deeper understanding of the relationship between changes in quality of life and changes in the relationship between voice-hearers and the voices they hear.
Interview participants will be selected from each of the eight participating centers. The sample will include individuals with relatively low levels of mental well-being and individuals with relatively high levels of mental well-being at T2, compared with the overall sample within each center. Participant selection will be carried out by the coordinating investigator. Selected participants will take part in an in-depth semi-structured interview conducted by the coordinating investigator. The analysis will be based on transcripts of these interviews, as well as reports from the review interviews conducted at T1, T1 + 4 months, and T2.
Thematic analyses will be performed by three researchers independent of the intervention groups and representing three disciplinary backgrounds: an advanced practice nurse, a sociologist, and a peer support worker with lived experience of hearing voices.
The themes identified by this multidisciplinary research team will be triangulated with a lexicometric analysis conducted using NVivo software.
Measures Implemented to Minimise Bias
- Use of a control group receiving an equivalent number of intervention hours and a comparable intervention format to the EDEN College group, in order to minimise confounding bias.
- Randomisation will be performed using randomly varying block sizes of 4 and 6 to ensure adequate balance between study arms while limiting the predictability of treatment allocation.
- Randomisation will be conducted through the REDCap platform. The investigator conducting the inclusion visit will be informed of the allocation. This investigator will schedule subsequent assessment visits with an associated researcher responsible for conducting the T1, T2, and T3 evaluations, while maintaining that researcher blinded to treatment allocation.
- Selection of a self-administered questionnaire, completed in the absence of group facilitators, as the primary outcome measure in order to minimise assessment bias.
- Use of self-report questionnaires or outcome assessments conducted under single-blind conditions for secondary outcomes to reduce assessment bias. The investigator conducting the T1, T2, and T3 assessments will remain blinded to treatment allocation through the randomisation procedure.
- Intention-to-treat analysis will be performed to minimise attrition bias.
- Qualitative interviews will be conducted by the coordinating investigator, who is not involved in delivering the interventions, in order to reduce follow-up and interviewer bias.
- Qualitative interview transcripts and related documents will be independently coded by three researchers and analysed using qualitative data analysis software (NVivo®) to reduce subjective interpretation bias.
- Triangulation of coded qualitative data by researchers from different disciplinary backgrounds and knowledge traditions (sociology, nursing science, and experiential expertise) will be used to minimise subjectivity bias.
- Participation in Accept Voices© interventions and Hearing Voices Groups delivered by healthcare professionals within the participating centres will not be permitted throughout the study period, due to their conceptual proximity to certain components of the EDEN College and the resulting risk of confounding.
- Different facilitators will be assigned to the CAU groups and the EDEN College to ensure comparable levels of facilitator engagement and to minimise contamination between intervention methods.
- The five self-report questionnaires will be completed in the presence of a healthcare professional (without assistance except to clarify items that are not understood). In addition, questionnaire administration will be divided across two appointments at each assessment time point to reduce participant burden and minimise attrition bias.
- Information regarding all psychiatric consultations and therapeutic encounters received in parallel with study participation will be collected monthly from both clinical records and participant reports throughout the inclusion and follow-up period in order to minimise confounding bias.
- Information on antipsychotic, mood stabiliser, antidepressant, and anxiolytic medications will be collected at T1, T2, and T3 to account for potential confounding effects of pharmacological treatment.
Data Collected (data will be recorded directly in the electronic Case Report Forms):
Demographic data: age and gender. Psychiatric diagnostic status: psychiatric diagnosis according to DSM-5 criteria or absence of a psychiatric diagnosis.
Type and dosage of prescribed psychotropic medications at T1, T2, and T3, (antipsychotics, mood stabilizers, antidepressants, and/or anxiolytics).
Name of the treating psychiatrist or the Advanced Practice Nurse (APN) responsible for the participant's care.
Presence of a legal protective measure concerning property or financial affairs, and the nature of such measure.
Name of the legal representative, where applicable. Responses and scores for the eight psychometric instruments administered at T1, T2, and T3: WEMWBS, ISMI, RSE, PSYRATS-AH, ARHS, HCS, BAVQ-R, and VAAS-9.
Reports of participant review interviews conducted at T1, T1 + 4 months, and T2 (transcripts or digital copies).
Full transcripts of the in-depth qualitative interviews conducted with the 18 to 24 participants selected for the qualitative component.
Monthly summary records of psychiatric care services received outside the study during the participant's 21-month study participation period.
